orog

Surface Altitude (m)

The parameter is the altitude of the Earth's surface or the geometric height of the surface above the geoid. It is the lower boundary of the UK Met Office Unified Model over land and describes the physical features and elevation variations across landscapes. It is also known as surface geopotential height. This parameter does not vary in time.

BARRA-C2/AUST-04/fx, BARRA-R2/AUS-11/fx, BARRA-R2/AUST-11/fx, BARRA-RE2/AUS-22/fx

sftlf

Percentage of the grid cell occupied by land (including lakes) (%)

Percentage of the modelling grid box occupied by land, including lakes.

BARRA-C2/AUST-04/fx, BARRA-R2/AUS-11/fx, BARRA-R2/AUST-11/fx, BARRA-RE2/AUS-22/fx

flashrate

Flash rate of lightning (m-2 s-1)

This parameter is the lightning flash density, the number of lightning flashes that occur over a specific area within a given time period. This is expressed as flashes per second per square metre (m-2 s-1). This includes intracloud and cloud-to-ground lightning discharges.

BARRA-C2/AUST-04/1hr

fogfraction

Fog fraction at 1.5m (1)

This parameter indicates how much of a given area is experiencing fog. It is represented by the fraction of model grid box covered by fog, at 1.5m (screen-level) above the surface of land, sea or inland waters, ranging from 0 (no fog) to 1 (entirely fog-covered).

BARRA-C2/AUST-04/1hr

hfls

Surface Upward Latent Heat Flux (W m-2)

This parameter is the transfer of heat from the Earth's surface to the atmosphere through evaporation from water bodies (oceans, lakes, soil) and evapotranspiration from plants. It is a flux parameter to indicate it is a quantity expressed as per unit area. It is useful for understanding the energy and water cycles influencing weather patterns and changes in surface temperatures.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

hfss

Surface Upward Sensible Heat Flux (W m-2)

This parameter is the transfer of heat from the Earth's surface to the atmosphere through conduction and convection, due to the temperature differences between the surface and the air. It is a flux parameter to indicate it is a quantity expressed as per unit area. It is useful for understanding the energy exchange between the surface and the atmosphere, which influences weather patterns.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

hurs

Near-Surface Relative Humidity (%)

This parameter is the amount of water vapour present in the air at 1.5m (screen-level) above the surface of land, sea or inland waters. It is expressed as a percentage of the amount of water vapour in the air to the maximum amount the air can hold at a given temperature.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

huss

Near-Surface Specific Humidity (1)

This parameter is the amount of water vapour present in the air at 1.5m (screen-level) above the surface of land, sea or inland waters. It is expressed as the ratio of the mass of water vapour to the total mass of moist air, expressed as kilogram of water vapour per kilogram of moist air.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

ps

Surface Air Pressure (Pa)

This parameter is the pressure of the atmosphere at the surface of land, sea and inland water. Its units are pascals (Pa) and can be converted to units of hPa or millibars using the conversion 1 hPa = 1 mb = 100 Pa.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

psl

Sea Level Pressure (Pa)

This parameter is the pressure of the atmosphere at the surface of the Earth, at the height of mean sea level, independent of the surface terrain. Its units are pascals (Pa) and can be converted to units of hPa or millibars using the conversion 1 hPa = 1 mb = 100 Pa. This parameter is the quantity often abbreviated as MSLP or PMSL.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

sfcWind* (sfcWind, sfcWindmax, sfcWind10minmean)

Near-Surface Wind Speed (m s-1)

This parameter is the wind speed at 10 metre above the surface of the Earth. The parameter is available as instantaneous, time-averaged and time-maximum quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

tas* (tas, tasmax, tasmean, tasmin)

Near-Surface Air Temperature (K)

This parameter refers to the temperature of air at 1.5m (screen-level) above the surface of land, sea or inland waters. 1.5m temperature is calculated by interpolating from the surface to 1.5m. This parameter has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available with different time profiles, instantaneous in time or averaged, minimum or maximum across regular time intervals.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

tauu

Surface Downward Eastward Wind Stress (Pa)

This parameter is the force, per unit area, exerted by the wind the Earth's surface in a downward and eastward direction. Positive (negative) values indicate stress on the surface of the Earth in an eastward (westward) direction. The parameter can combine with the northward component (tauv) to estimate the overall wind stress.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

tauv

Surface Downward Northward Wind Stress (Pa)

This parameter is the force, per unit area, exerted by the wind the Earth's surface in a downward and northward direction. Positive (negative) values indicate stress on the surface of the Earth in a northward (southward) direction. The parameter can combine with the eastward component (tauu) to estimate the overall wind stress.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

twiso* (twiso, twisomax)

Isobaric wet-bulb temperature (K)

Isobaric wet-bulb temperature (also known as thermodynamic wet-bulb temperature) is the temperature an air parcel would have if cooled to saturation at constant pressure by the evaporation of water into it, with all latent heat supplied by the parcel (American Meteorological Society, 2025). It closely approximates the temperature measured by a wet-bulb thermometer and is always greater than the pseudo wet-bulb temperature, with larger differences at higher temperatures and lower relative humidities (Warren, 2025). This parameter is also available as daily and monthly maxima.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

The near-surface isobaric wet-bulb temperature is calculated from near-surface temperature (tas), near-surface specific humidity (huss), and surface pressure (ps) using an analytical formula similar to Eq. 81 in Warren (2025) but neglecting ice processes. This implicit equation is solved using Newton's method starting from an initial guess obtained using the one-third rule (Knox et al., 2017). The calculation was performed using the atmos Python library (

https://github.com/robwarrenwx/atmos

).

twpse* (twpse, twpsemax)

Pseudo wet-bulb temperature (K)

Pseudo wet-bulb temperature (also known as adiabatic wet-bulb temperature) is the temperature an air parcel would have if lifted adiabatically to saturation and then brought pseudoadiabatically back to its original pressure, maintaining saturation via the evaporation of water into it, with all latent heat supplied by the parcel (American Meteorological Society, 2025). It is the wet-bulb temperature read off a thermodynamic diagram and is always less than the isobaric wet-bulb temperature, with larger differences at higher temperatures and lower relative humidities (Warren, 2025). This parameter is also available as daily and monthly maxima.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

The near-surface pseudo wet-bulb temperature is calculated from near-surface temperature (tas), near-surface specific humidity (huss), and surface pressure (ps) using the NEWT (non-iterative evaluation of wet-bulb temperature) method (Rogers and Warren, 2024), as implemented in the atmos Python library (

https://github.com/robwarrenwx/atmos

).

uas* (uas, uasmax, uasmean)

Eastward Near-Surface Wind (m s-1)

This parameter is the eastward component of the wind at 10 metre above the surface of the Earth. When positive, it is the horizontal speed of air moving towards the east, and when negative, it is towards the west. It can be combined with the northward component of wind (vas<CCCC>) to give the speed and direction of the horizontal wind. The parameter is available as instantaneous, time-averaged and time-maximum quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

vas* (vas, vasmax, vasmean)

Northward Near-Surface Wind (m s-1)

This parameter is the northward component of the wind at 10 metre above the surface of the Earth. When positive, it is the horizontal speed of air moving towards the north, and when negative, it is towards the south. It can be combined with the eastward component of wind (uas<CCCC>) to give the speed and direction of the horizontal wind. The parameter is available as instantaneous, time-averaged and time-maximum quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

visibility

Visibility at 1.5m (m)

This parameter is the maximum distance at which objects can be clearly seen, at 1.5 metre above the surface. The visibility can be influenced by fog, rain, snow and other weather phenomena.

BARRA-C2/AUST-04/1hr

wsgs* (wsgs, wsgsmax)

Near-Surface Wind Speed of Gust (m s-1)

This parameter is the maximum of the wind, at 10 metre above surface, averaged over 3 second intervals. The parameter is also available as time-maximum quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

As 3 seconds is much shorter than the model timestep, a parameterisation scheme is used to derive the maximum wind gust within each timestep.

pr

Precipitation (kg m-2 s-1)

This parameter is the rate of total precipitation, comprising rain and snow, at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. In the case where the UK Met Office Unified Model was set up with a horizontal grid spacing of 10 km or longer, the parameter combines the contributions from the convection scheme and the cloud scheme. The rate of precipitation produced by the convection scheme is available in the parameter prc, and that produced by the cloud scheme is available in the parameter prra.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

prc

Convective Precipitation (kg m-2 s-1)

This parameter is the rate of precipitation, comprising rain and snow, at the surface, generated by the convection parameterisation scheme in the UK Met Office Unified Model when set up with a horizontal grid spacing of 10 km or longer. The convection scheme estimates sub-grid scale convection and precipitation at spatial scales smaller than the grid length. This differs from the precipitation generated by the cloud scheme in the Unified Model, which describes the formation and dissipation of clouds and precipitation due to changes in atmospheric conditions simulated at spatial scales of the grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines the contributions from the convection scheme and the cloud scheme is available in the parameter pr. The contribution simulated by the cloud scheme is available in the parameter prra.

BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

prga

Graupel Sediment Rate (kg kg-1 s-1)

This parameter is the rate of graupel at the surface, estimated by the cloud scheme in the UK Met Office Unified Model. Graupels forms when supercooled water droplets freeze onto falling snowflakes. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min

prhmax

Monthly Mean Daily Maximum Hourly Precipitation Rate (kg m-2 s-1)

This parameter is the daily maximum hourly rate of total precipitation, comprising rain and snow, at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. In the case where the UK Met Office Unified Model was set up with a horizontal grid spacing of 10 km or longer, the parameter combines the contributions from the convection scheme and the cloud scheme.

BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

prmax

Hourly Maximum Precipitation Rate (kg m-2 s-1)

This parameter is the hourly maximum rate of total precipitation, comprising rain and snow, at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. In the case where the UK Met Office Unified Model was set up with a horizontal grid spacing of 10 km or longer, the parameter combines the contributions from the convection scheme and the cloud scheme.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUS-11/1hr, BARRA-RE2/AUS-22/1hr

prra

Large Scale Rainfall Rate (kg m-2 s-1)

This parameter is the rate of precipitation, comprising rain and snow, at the surface, generated by the cloud scheme in the UK Met Office Unified Model. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines both rain and snow is available in the parameter pr.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min

prsn

Snowfall Flux (kg m-2 s-1)

This parameter is the rate of snow at the surface, generated by the cloud scheme in the UK Met Office Unified Model. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines both rain and snow is available in the parameter pr.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

prsnmax

Hourly Maximum Snowfall Flux (kg m-2 s-1)

This parameter is the hourly maximum rate of snow at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second.

BARRA-C2/AUST-04/1hr

prw

Water Vapor Path (kg m-2)

This parameter is the integrated mass of water vapour in a vertical column of the atmosphere, extending from the Earth's surface to the top of the atmosphere. It is useful for predicting precipitation and studying humidity levels.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

This parameter is likely very similar to PW. Some difference may be due to the range of vertical levels across which integration was made.

ares

Aerodynamic Resistance (s m-1)

This parameter is the aerodynamic resistance in an atmospheric model. It is a measure of how easily air can move between the land surface and the first atmospheric model level. The resistance depends on wind speed, surface roughness, and atmospheric stability, and indicates how different land surfaces interact with the atmosphere.

BARRA-C2/AUST-04/3hr

cw

Total Canopy Water Storage (kg m-2)

This parameter is a measure of the amount of water stored in the canopy for each model grid box, expressed in the units of kg m-2 (per unit area). It does not include soil moisture or precipitation.

BARRA-C2/AUST-04/3hr

evspsbl

Evaporation Including Sublimation and Transpiration (kg m-2 s-1)

The rate of evapotranspiration from the surface to the atmosphere. This includes evaporation from the sea surface, evaporation from the soil surface, transpiration from plants and evaporation from the vegetative canopy.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

evspsblpot

Potential Evapotranspiration (kg m-2 s-1)

This parameter is the potential evapotranspiration (PET), the ET that would occur if the soil and vegetation are saturated. It is a flux parameter to indicate it is a quantity expressed as per unit area, per second. The PET scales with the friction velocity for each tile type (e.g., grass, shrub, broadleaf tree, bare soil), which depends on the canopy heights etc. PET is computed by the model for each tile type and the average across the tiles are computed and published. It is of note that the energy constraint is not imposed on the calculation of this diagnostic in the model, which is different from using the Penman-Monteith equation. In other words, the PET diagnostic is simply driven by a surface to atmosphere humidity difference.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrfso

Soil Frozen Water Content (kg m-2)

The total mass of frozen water per unit area summed over the four soil layers. This parameter has two spatial coordinates. There are four soil levels, representing a total depth of (0-3m) below the surface. Units are kg/m2. This parameter is valid on land points only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrfsol

Frozen Water Content of Soil Layer (kg m-2)

The total mass of frozen water per unit area in each soil layer. This parameter has three spatial coordinates, with the third representing the soil level. There are four soil levels, representing (0-10cm), (10-35cm), (35cm-1m) and (1m-3m) below the surface. Units are kg/m2. This parameter is valid on land points only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrfsos

Frozen Water Content in Upper Portion of Soil Column (kg m-2)

The mass of frozen moisture per unit area in the top soil layer. Units are kg/m2. The top soil layer represents the top 10-cm below the surface.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrro

Total Runoff (kg m-2 s-1)

The total rate of runoff per unit area, precipitation which hits the ground and moves away rather than being absorbed by the soil. Units are kg/m2/s. This parameter represents the sum of both surface and subsurface runoff. A river routing model has not been applied, so runoff is removed from the system as soon as it forms. This parameter is valid on land points only.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrros

Surface Runoff (kg m-2 s-1)

The rate of surface runoff per unit area, precipitation which hits the ground and moves away rather than being absorbed by the soil. Units are kg/m2. This parameter represents the surface runoff only. A river routing model has not been applied, so runoff is removed from the system as soon as it forms. This parameter is valid on land points only.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrso

Total Soil Moisture Content (kg m-2)

The total mass of moisture summed over the four soil layers. This parameter has two spatial coordinates. There are four soil levels, representing a total depth of (0-3m) below the surface. Units are kg/m2. Divide by the soil level depths (3 m) and by the density of water (1000 kg/m3) to convert into the moisture fraction. This parameter is valid on land points only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrsol

Total Water Content of Soil Layer (kg m-2)

The total mass of moisture per unit area in each soil layer. This parameter has three spatial coordinates, with the third representing the soil level. There are four soil levels, representing (0-10cm), (10-35cm), (35cm-1m) and (1m-3m) below the surface. Units are kg/m2. Divide by the soil level depths (0.1, 0.25, 0.65 and 2 m) and by the density of water (1000 kg/m3) to convert into the moisture fraction. This parameter is valid on land points only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

mrsos

Moisture in Upper Portion of Soil Column (kg m-2)

The mass of moisture per unit area in the top soil layer. Units are kg/m2. The top soil layer represents the top 10-cm below the surface. This parameter is valid on land points only.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

sfcMoisflx

Surface Total Moisture Flux (kg m-2 s-1)

The total moisture flux per unit area between the surface and the atmosphere. This parameter does not include precipitation.

BARRA-C2/AUST-04/3hr

snd

Snow Depth (m)

This parameter represents the instantaneous depth of snow on top of the land surface. It has units of metres. It is valid on land grid-cells only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

snm

Surface Snow Melt (kg m-2 s-1)

This is the rate at which the snow mass per unit area on top of the land surface melts. It has units of kg/m2/s. It is valid on land grid-cells only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

snw

Surface Snow Amount (kg m-2)

This parameter is the mass of snow per unit area present on the land surface. It has units of kg/m2. It is present on land grid-cells only.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

soildrainage

Drainage out of Soil Model (kg m-2 s-1)

This parameter is the rate of water drains freely from the bottom of the soil column in the Joint UK Land Simulator (JULES). The version of the model does not include a water table or groundwater flow. This parameter is valid on land grid-cells only.

BARRA-C2/AUST-04/3hr

throughfall

Canopy Throughfall Rate (kg m-2 s-1)

The rate per unit area that water falls through the vegetative canopy. Units are kg/m2/s.

BARRA-C2/AUST-04/3hr

ts* (ts, tsmean)

Surface Temperature (K)

This parameter is the temperature of the land or sea/sea-ice surface of the Earth. Over land, this is the surface skin temperature. On ice-free sea areas, it is the temperature of sea surface. On sea areas with ice, it is a ice fraction weighted sum of temperature of top ice layer and freezing point of sea water. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available as instantaneous and time-averaged quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

tsl

Temperature of Soil (K)

This parameter is the temperature of the soil at 4 soil layers. The model has a four-layer representation of soil column. The depth of first (topmost) soil layer is 0 to 10 cm where the surface is at 0 cm. The second layer is 10 to 35 cm, with a thickness of 20 cm. The third layer is 35 cm to 1 metre, with a thickness of 65 cm. The last (deepest) layer is 1 metre to 3 metres, with a thickness of 2 metre. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15.

BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

z0

Surface Roughness Length (m)

This parameter quantifies the roughness of the Earth's surface due to various roughness elements such as vegetation and terrain features, which affects the flow of air over it. It represents the height above the ground at which the wind speed theoretically becomes zero due to the surface's roughness element. The parameter can be useful for predicting how wind speed changes with height.

BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

hus* (hus10, hus100, hus150, hus1000, hus150, hus20, hus200, hus250, hus30, hus300, hus400, hus50, hus500, hus600, hus70, hus700, hus750, hus800, hus850, hus900, hus925, hus950, hus975)

Specific Humidity (1)

This parameter is the ratio of the mass of water vapour to the total mass of air, expressed as kilogram of water vapour per kilogram of moist air. The total mass of moist air includes the mass of the dry air, water vapour, cloud liquid and ice, rain and snow. This is available at multiple pressure levels in the atmosphere.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

omega500

Downward Air Velocity in pressure coordinates (Pa s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a pressure-based vertical coordinate system and has units of pascals per second. Since atmospheric pressure decreases with height, positive values corresponds downward motion and negative values indicate upward motion.

BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

This parameter is identical to wap500.

radrefl1km

Radar reflectivity at 1km altitude (dBZ)

This parameter represents the radar reflectivity at an altitude of 1 km above the surface. This altitude is typically used for comparisons between model simulated reflectivity with network radars. The units are dBZ and has a lower bound of -40 dBZ when there is no cloud or precipitation. The reflectivity assumes contributions from rain, snow, graupel and liquid cloud.

BARRA-C2/AUST-04/20min

ta* (ta10, ta100, ta1000, ta150, ta20, ta200, ta250, ta30, ta300, ta400, ta50, ta500, ta600, ta70, ta700, ta750, ta800, ta850, ta900, ta925, ta950, ta975)

Air Temperature (K)

This parameter refers to the temperature in the atmosphere. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available on multiple pressure levels through the atmosphere.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

ta*m (ta100m, ta1500m, ta150m, ta200m, ta250m, ta50m)

Air Temperature (K)

This parameter is the temperature in the atmosphere. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available at multiple geometric heights above the surface of the Earth.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

ua* (ua10, ua100, ua1000, ua150, ua20, ua200, ua250, ua30, ua300, ua400, ua50, ua500, ua600, ua70, ua700, ua750, ua800, ua850, ua900, ua925, ua950, ua975)

Eastward Wind (m s-1)

This parameter is the northward component of the wind, at a pressure level in the atmosphere, as given in the variable name. When positive, it is the horizontal speed of air moving towards the east, and when negative, it is towards the west. It can be combined with the northward component of wind (va<NNN>) to give the speed and direction of the horizontal wind. This parameter is available on multiple pressure levels through the atmosphere.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

ua*m (ua100m, ua1500m, ua150m, ua200m, ua250m, ua50m)

Eastward Wind (m s-1)

This parameter is the eastward component of the wind, at a height of some metres above the surface, as given in the variable name. When positive, it is the horizontal speed of air moving towards the east, and when negative, it is towards the west. It can be combined with the northward component of wind (va<NNN>m) to give the speed and direction of the horizontal wind. This parameter is available at multiple geometric heights above the surface of the Earth.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

va* (va10, va100, va1000, va150, va20, va200, va250, va30, va300, va400, va50, va500, va600, va70, va700, va750, va800, va850, va900, va925, va950, va975)

Northward Wind (m s-1)

This parameter is the northward component of the wind, at a pressure level in the atmosphere, as given in the variable name. When positive, it is the horizontal speed of air moving towards the north, and when negative, it is towards the south. It can be combined with the eastward component of wind (ua<NNN>) to give the speed and direction of the horizontal wind. This parameter is available on multiple pressure levels through the atmosphere.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

va*m (va100m, va1500m, va150m, va200m, va250m, va50m)

Northward Wind (m s-1)

This parameter is the northward component of the wind, at a height of some metres above the surface, as given in the variable name. When positive, it is the horizontal speed of air moving towards the north, and when negative, it is towards the south. It can be combined with the eastward component of wind (ua<NNN>m) to give the speed and direction of the horizontal wind. This parameter is available at multiple geometric heights above the surface of the Earth.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

wa* (wa10, wa100, wa150, wa1000, wa150, wa20, wa200, wa250, wa30, wa300, wa400, wa50, wa500, wa600, wa70, wa700, wa750, wa800, wa850, wa900, wa925, wa950, wa975)

Upward Air Velocity (m s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a geometric vertical coordinate system and has units of metres per second, and is different from wap<NNN> that is expressed in a pressure-based vertical coordinate system. Positive values correspond upward motion and negative values indicate upward motion.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

wap* (wap10, wap100, wap150, wap1000, wap150, wap20, wap200, wap250, wap30, wap300, wap400, wap50, wap500, wap600, wap70, wap700, wap750, wap800, wap850, wap900, wap925, wap950, wap975)

Upward air velocity in pressure/second (Pa s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a pressure-based vertical coordinate system and has units of pascals per second, and is different from wa<NNN> that is expressed in a geometric vertical coordinate system. Since atmospheric pressure decreases with height, positive values corresponds downward motion and negative values indicate upward motion.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon

zg* (zg10, zg100, zg150, zg1000, zg150, zg20, zg200, zg250, zg30, zg300, zg400, zg50, zg500, zg600, zg70, zg700, zg750, zg800, zg850, zg900, zg925, zg950, zg975)

Geopotential Height (m)

This parameter is the height of a specific pressure level above mean sea level. It is commonly used for analysis of weather patterns. Synoptic charts of geopotential height plotted at constant pressure levels can be used to identify weather systems such as troughs, ridges, cyclones, and anticyclones. The parameter can be converted to geopotential, which is the gravitational potential energy of a unit mass relative to mean sea level, multiplying with the Earth's gravitational acceleration g of 9.80665 m s-2.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/3hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/3hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/3hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

zmla

Height of Boundary Layer (m)

This parameter is the depth of the atmosphere boundary layer, in units of m. The boundary layer is the lowest part of the atmosphere that directly interacts with the Earth's surface.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

ztp

Tropopause height (m)

Height of the model identified tropopause, in units of m. The tropopuse height is the boundary between the troposphere and the stratosphere. Thunderstorms and convection are capped by the tropopause so its height can indicate how tall are the storms. Further, jet streams often flow near the tropospause.

BARRA-C2/AUST-04/1hr

clh

High Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the high levels of the troposphere between ICAO (International Civil Aviation Organization) 500 and 150 hPa levels (5574m and 13608m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

clivi

Ice Water Path (kg m-2)

This parameter is the total mass of ice particles suspended in clouds within a vertical column of the atmosphere, represented over a unit area. This parameter has units of kg/m2.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

cll

Low Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the lower levels of the troposphere between ICAO (International Civil Aviation Organization) 1000hPa and 800Pa levels (111m and 1949m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

clm

Mid Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the middle levels of the troposphere between ICAO (International Civil Aviation Organization) 800hPa and 500Pa levels (1949m and 5574m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

clt

Total Cloud Cover Percentage (%)

This parameter is the proportion of a grid box covered by cloud occurring at all model levels through the atmosphere. The parameter is calculated under maximum-random overlap assumption.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

clwvi

Condensed Water Path (kg m-2)

The vertical integral of liquid water mass contained in clouds. This parameter has units of kg/m2.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

coltotdrym

Total column dry mass (kg m-2)

This parameter is the total mass of dry air, excluding water vapour, precipitation and cloud condensates like cloud water or cloud ice, in a vertical column of the atmosphere. It has units of kg/m2. Together with coltotwetm parameter, it is useful for studying the movement of moisture and gases in the atmosphere.

BARRA-C2/AUST-04/1hr

coltotwetm

Total column wet mass (kg m-2)

This parameter is the total mass of all atmospheric constituents, including water vapour, precipitation, cloud condensates and dry air, in a vertical column of the atmosphere. It has units of kg/m2. It is useful for studying the movement of mass in the atmosphere.

BARRA-C2/AUST-04/1hr

helicity* (helicity, helicitymax, helicitymin)

Updraft Helicity (2000-5000m) (m2 s-2)

This parameter is a measure of the rotation within a storm's updraft, combining vertical velocity (updraft speed) and vertical vorticity (rotation). This is calculated by integrating the product of updraft speed and vorticity over a specific depth of the atmosphere 2-5 km AGL. It is useful for identifying areas where strong, rotating updrafts are likely to occur, which is associated with severe weather events like supercells and tornadoes. The parameter is available as instantaneous, time-maximum and time-minimum quantities.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min

maxcolrefl

Maximum Radar Reflectivity in the grid column due to all hydrometeors (dBZ)

This parameter represents the maximum value of radar reflectivity in each model column, defined as extending from the surface to the top of the model (40-80 km). It includes contributions from all hydrometeors, namely rain, snow, graupel and liquid cloud. Its units are dBZ and a minimum value of -40 dBZ is set where there is no cloud or precipitation.

BARRA-C2/AUST-04/1hr

maxcolwa

Maximum vertical wind speed in column (m s-1)

This parameter is the maximum value of speed of vertical air motion in each model column. It is expressed with a geometric vertical coordinate system and has units of metres per second. Positive values correspond upward motion and negative values indicate upward motion.

BARRA-C2/AUST-04/1hr

qfluxu

Eastward column-integrated moisture flux (kg m-1 s-1)

This parameter is the movement of water vapour in the atmosphere from west to east, integrated over the vertical column of the atmosphere. It is useful for understanding the transport of moisture across regions, affecting weather patterns and precipitation.

BARRA-C2/AUST-04/3hr, BARRA-R2/AUS-11/3hr, BARRA-RE2/AUS-22/3hr

qfluxv

Northward column-integrated moisture flux (kg m-1 s-1)

This parameter is the movement of water vapour in the atmosphere from south to north, integrated over the vertical column of the atmosphere. It is useful for understanding the transport of moisture across regions, affecting weather patterns and precipitation.

BARRA-C2/AUST-04/3hr, BARRA-R2/AUS-11/3hr, BARRA-RE2/AUS-22/3hr

rlds

Surface Downwelling Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation that.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rldscs

Surface Downwelling Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation that is emitted by the atmosphere and reaches the Earth's surface under clear-sky conditions. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rlus

Surface Upwelling Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted by the Earth's surface and the reflected atmospheric downward longwave radiation. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rluscs

Surface Upwelling Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted by the Earth's surface and the reflected atmospheric downward longwave radiation under clear-sky conditions. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rlut

TOA Outgoing Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted into space by the Earth and its atmosphere. It is also called the outgoing longwave radiation or OLR. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rlutcs

TOA Outgoing Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted into space by the Earth and its atmosphere without the interference of clouds. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsds

Surface Downwelling Shortwave Radiation (W m-2)

This parameter is the shortwave radiation from the Sun, incident on the Earth's surface. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area. It is a combination of direct and diffused solar radiation. Its direct component has not accounted for the solar zenith angle. This parameter can be treated as an estimate of global horizontal irradiance (GHI).

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsdscs

Surface Downwelling Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of solar radiation that reaches the Earth's surface under clear-sky conditions, without interference from clouds. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsdsdif

Surface diffused downwelling shortwave radiation (W m-2)

This parameter is the diffused shortwave radiation from the Sun, incident on the Earth's surface. It is a flux parameter to indicate it is a quantity expressed as per unit area. Different from the direct shortwave radiation, it consists of rays that arrive at the surface after scattering by clouds and particles in the atmosphere. The parameter has been corrected for the solar zenith angle.

BARRA-C2/AUST-04/20min

rsdsdir

Surface Direct Downwelling Shortwave Radiation (W m-2)

This parameter is the direct shortwave radiation from the Sun, incident on the Earth's surface. It is a flux parameter to indicate it is a quantity expressed as per unit area. Different from the diffused shortwave radiation, it consists of rays that come directly from the Sun's position in the sky. The parameter has been corrected for the solar zenith angle and the effect of topography.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/20min, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

A commonly used quantity direct normal irradiance (DNI) can be derived by dividing this parameter by the cosine of the solar zenith angle.

rsdt

TOA Incident Shortwave Radiation (W m-2)

This parameter is the amount of solar radiation that reaches the top of the Earth's atmosphere. This radiation is primarily shortwave. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rss

Net downward shortwave flux at surface (W m-2)

This parameter is the difference between the incoming and outgoing shortwave radiation at the Earth's surface. The incoming radiation includes direct sunlight and diffused sky radiation that reaches the surface, and the outgoing radiation is the portion of the incoming radiation that is reflected back into the atmosphere, mainly due to the surface's albedo. Its value is positive when the incoming radiation exceeds the outgoing. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/20min

rsus

Surface Upwelling Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into the atmosphere from the Earth's surface, mainly due to the surface's albedo. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsuscs

Surface Upwelling Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into the atmosphere from the Earth's surface under clear-sky conditions, mainly due to the surface's albedo. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsut

TOA Outgoing Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into space from the top of the Earth's atmosphere. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

rsutcs

TOA Outgoing Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into space from the top of the Earth's atmosphere, under clear-sky conditions. It does not include radiation reflected by cloud. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

sund

Monthly Mean Duration of Sunshine (s)

This parameter is the length of time, in a day, that the direct solar irradiance exceeds a threshold value of 120 W m2. It indicates the level of cloudiness and sunniness of a location.

BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

BWD01* (BWD01, BWD01dir)

0 to 1 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the 0-1 km BWD (BWD01) has been found to discriminate between tornadic and non-tornadic storms as well as between supercells and ordinary thunderstorms (Thompson et al. 2003, 2012). The direction of the 0-1 km BWD (BWD01dir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-3 km BWD to compute the 1-3 km BWD.

BARRA-R2/AUST-11/1hr

The lowest model level is used in place of 0 km AGL.

BWD03* (BWD03, BWD03dir)

0 to 3 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the 0-3 km BWD (BWD03) is a component of the fixed-layer SHERB (severe hazards in environments of reduced buoyancy) parameter, a diagnostic developed in the US for forecasting severe weather in high-shear, low-CAPE environments (Sherburn and Parker 2014). The direction of the 0-3 km BWD (BWD03dir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-1 km BWD to compute the 1-3 km BWD or in combination with the components of the 0-6 km BWD to compute the 3-6 km BWD.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The lowest model level is used in place of 0 km AGL.

BWD06* (BWD06, BWD06dir)

0 to 6 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the 0-6 km BWD (BWD06) has been found to discriminate between supercells and ordinary thunderstorms (Rasmussen and Blanchard 1998; Thompson et al. 2003) and is thus a useful diagnostic for severe weather, such as large hail and tornadoes (e.g., Rasmussen 2003; Thompson et al. 2012; Taszarek et all. 2020). BWD06 is a component of the original fixed-layer supercell composite parameter (SCP) and significant tornado parameter (STP), diagnostics developed in the US for forecasting supercell thunderstorms and tornadoes, respectively (Thompson et al. 2003). It is also a component of the significant hail parameter (SHIP) and the derecho composite parameter (DCP), diagnostics developed in the US for forecasting large hail and cold pool-driven severe convective wind gusts, respectively (Storm Prediction Center 2024a,c). BWD06 can additionally be combined with mixed-layer or most-unstable CAPE to calculate WMAXSHEAR, a simple composite parameter that shows skill in discriminating between and severe and non-severe thunderstorms (e.g., Taszarek et al. 2020). The direction of the 0-6 km BWD (BWD06dir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-3 km BWD to compute the 3-6 km BWD or in combination with the components of the 0-9 km BWD to compute the 6-9 km BWD.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The lowest model level is used in place of 0 km AGL.

BWD09* (BWD09, BWD09dir)

0 to 9 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of BWD over a deep layer, such as 0-9 km, has been found to discriminate between weak, severe, and derecho-producing mesoscale convective systems (Cohen et al. 2007). The direction of the 0-9 km BWD (BWD09dir) can be used in combination with its magnitude (BWD09) to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-6 km BWD to compute the 6-9 km BWD.

BARRA-R2/AUST-11/1hr

The lowest model level is used in place of 0 km AGL.

CAPE* (CAPE, CAPEmax)

Convective Available Potential Energy (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-R2/AUST-11/1hr, BARRA-R2/AUST-11/day, BARRA-R2/AUST-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

The surface-based (SB) parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

CIN* (CIN, CINmax)

Convective Inhibition (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. Note that CIN is undefined (NaN) where CAPE = 0.

BARRA-C2/AUST-04/1hr, BARRA-C2/AUST-04/day, BARRA-C2/AUST-04/mon, BARRA-R2/AUS-11/1hr, BARRA-R2/AUS-11/day, BARRA-R2/AUS-11/mon, BARRA-R2/AUST-11/1hr, BARRA-R2/AUST-11/day, BARRA-R2/AUST-11/mon, BARRA-RE2/AUS-22/1hr, BARRA-RE2/AUS-22/day, BARRA-RE2/AUS-22/mon

The surface-based (SB) parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

CRZdepth

Depth of Charge Reversal Zone (m)

The charge separation zone (CRZ) is defined as the layer from 0 to -2 degC (Bright et al. 2005). A shallower CRZ implies steeper lapse rates and potentially higher CAPE within the layer. The lapse rate within the CRZ can be calculated as 20 K / CRZdepth. CRZdepth can also be combined the freezing-level height (FZL) to calculate the height of the -20 degC level.

BARRA-R2/AUST-11/1hr

DCAPE

Downdraft Convective Available Potential Energy (J kg-1)

Downdraft convective available potential energy (DCAPE) is defined as minus the vertical integral of negative buoyancy between the downdraft parcel level (DPL) and the surface. It provides a measure of the energy available to a saturated descending parcel of air, which can be converted to horizontal momentum when the parcel reaches the surface. Higher values of DCAPE have been found to be more favourable for cold pool-driven severe convective windstorms, such as derechos (e.g., Evans and Doswell 2001; Kuchera and Parker 2006; Cohen et al. 2007). DCAPE is a component of the derecho composite parameter (DCP), a diagnostic developed in the US for forecasting cold pool-driven severe convective windstorms (Storm Prediction Center, 2024a). Note that DCAPE is undefined (NaN) where the downdraft parcel is undefined.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The downdraft parcel is defined using the properties at the level of minimum wet-bulb potential temperature between the most-unstable lifting condensation level (MULCL) and the mid-point between the MULCL and most-unstable equilibrium level (MUEL). Where the distance between the MULCL and MUEL is less than 2 km, the downdraft parcel is undefined. The parcel is assumed to descend pseudoadiabatically. Ice processes, entrainment, and pressure perturbations are all neglected.

DPL

Downdraft Parcel Level (m)

The downdraft parcel level (DPL) is the level from which the downdraft parcel descent is initialised. It is specified as the level of minimum wet-bulb potential temperature between the most-unstable lifting condensation level (MULCL) and the mid-point between the MULCL and most-unstable equilibrium level (MUEL). All else being equal, a higher DPL is associated with larger downdraft CAPE (DCAPE) suggesting conditions more favourable for severe convective wind events. Note that DPL is undefined (NaN) where the downdraft parcel is undefined.

BARRA-R2/AUST-11/1hr

The downdraft parcel is defined using the properties at the level of minimum wet-bulb potential temperature between the most-unstable lifting condensation level (MULCL) and the mid-point between the MULCL and most-unstable equilibrium level (MUEL). Where the distance between the MULCL and MUEL is less than 2 km, the downdraft parcel is undefined. The parcel is assumed to descend pseudoadiabatically. Ice processes, entrainment, and pressure perturbations are all neglected.

EBWD* (EBWD, EBWDdir)

Effective Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the effective BWD (EBWD) has been found to discriminate between supercells and ordinary thunderstorms (Thompson et al. 2007) and is thus a useful diagnostic for severe weather, such as large hail and tornadoes (e.g. Rasmussen 2003; Thompson et al. 2012; Taszarek et all. 2020). EBWD is a component of the effective-layer supercell composite parameter (SCP) and significant tornado parameter (STP), diagnostics developed in the US for forecasting supercell thunderstorms and tornadoes, respectively (Thompson et al. 2007). It is also a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a) and is used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020) and in the Additive Regression Convective Hazard Models (AR-CHaMo) for large and very large hail (Battaglioli et al. 2023). EBWD can additionally be combined with mixed-layer or most-unstable CAPE to calculate an effective-layer version of WMAXSHEAR, a simple composite parameter that shows skill in discriminating between and severe and non-severe thunderstorms (e.g., Taszarek et al. 2020). The direction of the effective BWD (EBWDdir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. Note that EBWD and EBWDdir are undefined (NaN) where the effective inflow layer (EIL) is undefined.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

Following Thompson et al. (2007), EBWD is defined as the vector difference between the winds at the effective inflow layer (EIL) base and half of the most-unstable equilibrium level (MUEL).

EFFCAPE

Convective Available Potential Energy for Effective Parcel (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur. Note that EFFCAPE is undefined (NaN) where the EIL is undefined.

BARRA-R2/AUST-11/1hr

The effective (EFF) parcel is defined using the average potential temperature and specific humidity over the effective inflow layer (EIL), together with the pressure at the centre of the EIL. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

EFFCIN

Convective Inhibition for Effective Parcel (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. Note that EFFCIN is undefined (NaN) where the EIL is undefined.

BARRA-R2/AUST-11/1hr

The effective (EFF) parcel is defined using the average potential temperature and specific humidity over the effective inflow layer (EIL), together with the pressure at the centre of the EIL. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

EIL* (EILbase, EILdepth)

Effective Inflow Layer Base Height AGL (m)

The effective inflow layer (EIL) describes a layer of air that has sufficiently high convective available potential energy (CAPE) and sufficiently low convective inhibition (CIN) to support thunderstorm development and maintenance (Thompson et al. 2007). Idealised numerical simulations suggest that the EIL reasonably encapsulates the true inflow layer for most storm types, with better performance for supercell storms (Nowortarski et al. 2020). The EIL is used in the calculation of effective bulk wind difference (EBWD) and effective storm-relative helicity (ESRH). It can also be used to define effective CAPE and CIN. If the base of the EIL (EILbase) is above the boundary-layer top, this suggests that the environment is more favourable for elevated thunderstorms (particularly if the surface-based or mixed-layer CAPE are small). The depth of the EIL (EILdepth) can be used in combination with EILbase to calculate the height of the EIL top. Note that EILbase and EILdepth are undefined (NaN) where the EIL is undefined.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

Following Thompson et al. (2007), the EIL is defined as the first contiguous layer above the surface with CAPE > 100 J/kg and CIN < 250 J/kg. Where no levels or only a single level meet these criteria, the EIL is undefined (NaN). The base of the EIL must be below both the 500 hPa level and the -20 degC level.

EML* (EMLbase, EMLdepth, EMLlapse)

Height AGL of Base of Elevated Mixed Layer (m)

An EML is an elevated layer featuring nearly dry adiabatic lapse rates and relatively high potential temperature, typically with a capping inversion at its base. EMLs originate as well-mixed, deep atmospheric boundary layers formed via intense surface heating over elevated arid regions. Air within the layer is subsequently advected over potentially cooler but moister boundary-layer air at lower elevations. This configuration typically favours large convective available potential energy (CAPE) but also substantial convective inhibition (CIN). EMLs are a common feature of severe weather environments in the US (Carlson et al. 1983; Banacos and Ekster 2010; Cordeira et al. 2017) but have been observed in association with severe storms in many other parts of the world, including Australia.

BARRA-R2/AUST-11/1hr

Following previous studies in the US (Banacos and Ekster 2010; Cordeira et al. 2017), EMLs are identified as contiguous layers, at least 1000 m in depth, with a temperature lapse rate of at least 8 K/km and higher relative humidity at the top of the layer than the base. The base of the layer must be above 500 m AGL and below the -10 degC level. The lapse rate immediately below the EML base must be < 8 K/km to ensure that it is not part of a surface-based mixed layer. In the case of multiple EMLs within a single profile, only the lowest one is retained.

ESRH* (ESRHl, ESRHr)

Effective Storm-Relative Helicity for Bunkers Left Mover (m2 s-2)

Storm-relative helicity (SRH) is defined as the vertical integral of the dot product of the storm-relative wind and streamwise vorticity vectors over a given layer. It provides a measure of the potential for updraft rotation and is thus a useful diagnostic for supercell thunderstorms and their associated hazards, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). The effective SRH (ESRH) is a component of the effective-layer supercell composite parameter (SCP) and effective-layer significant tornado parameter (STP), diagnostics developed in the US for forecasting supercell thunderstorms and tornadoes, respectively (Thompson et al. 2007). Note that ESRHl and ESRHr are undefined (NaN) where the EIL is undefined.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

SRH is calculated using Eq. 8.15 from Markowski and Richardson (2010). The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted mean wind between the effective inflow layer (EIL) base and 65 % of the most-unstable equilibrium level (MUEL).

FZL

Freezing Level Height AGL (m)

The freezing level (FZL) is defined as the height above ground level (AGL) at which the environmental temperature first drops below 0 degC. A higher FZL is indicative of a warmer environment, which may be more favourable for thunderstorms but less favourable for hail (particularly small hail) due to enhanced melting. FZL is a component of the improved instability-shear hail proxy for Australia developed by Raupach et al. (2023). Note that FZL is undefined (NaN) where the temperature at the lowest model level is below 0 degC.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

HGZdepth

Depth of Hail Growth Zone (m)

The hail growth zone (HGZ) is defined as the layer from -10 to -30 degC (Johnson and Sugden 2014). A shallower HGZ implies steeper lapse rates and potentially higher CAPE within the layer. The lapse rate within the HGZ can be calculated as 20 K / HGZdepth. HGZdepth is a component of the large hail parameter (LHP), a diagnostic developed in the US for forecasting hail greater than 2 inches (~5 cm) in diameter (Johnson and Sugden 2014).

BARRA-R2/AUST-11/1hr

LR01

0 to 1 km AGL Lapse Rate (K m-1)

The 0-1 km lapse rate (LR01) is defined as the difference in temperature between the surface and 1 km above ground level (AGL) divided by the layer depth. Large values of LR01 may be favourable for severe convective winds as they will promote a more rapid decrease in buoyancy for descending saturated parcels. LR01 can be combined with the 0-3 km lapse rate (LR03) to compute the 1-3 km lapse rate, which is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a).

BARRA-R2/AUST-11/1hr

The lowest model level is used in place of 0 km AGL.

LR03

0 to 3 km AGL Lapse Rate (K m-1)

The 0-3 km lapse rate (LR03) is defined as the difference in temperature between the surface and 3 km above ground level (AGL) divided by the layer depth. Large values of LR03 may be favourable for severe convective winds as they will promote a more rapid decrease in buoyancy for descending saturated parcels. LR03 is a component of the enhanced stretching potential (ESP), a diagnostic developed in the US for forecasting tornadoes (Storm Prediction Center, 2024b). It can also be combined with the 0-1 km lapse rate (LR01) to compute the 1-3 km lapse rate, which is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The lowest model level is used in place of 0 km AGL.

LR24

2 to 4 km AGL Lapse Rate (K m-1)

The 2-4 km lapse rate (LR24) is defined as the difference in temperature between 2 and 4 km above ground level (AGL) divided by the layer depth. Large values of LR24 may be favourable for thunderstorms and severe weather as they will promote larger CAPE and stronger convective updrafts. They can also indicate the presence of an elevated mixed layer (EML) (e.g., Carlson et al. 1983). In the US and Europe, hail size has been shown to increase with LR24 and, in general, severe thunderstorms feature higher LR24 than ordinary thunderstorms (Taszarek et al. 2020).

BARRA-R2/AUST-11/1hr

Lapse rate is defined as the temperature at the bottom of the layer minus the temperature at the top of the layer, divided by the layer depth. Positive LR thus indicates decreasing temperatures with height across the layer.

LR36

3 to 6 km AGL Lapse Rate (K m-1)

The 3-6 km lapse rate (LR36) is defined as the difference in temperature between 3 and 6 km above ground level (AGL) divided by the layer depth. Large values of LR36 may be favourable for thunderstorms and severe weather as they will promote larger CAPE and stronger convective updrafts. They can also indicate the presence of an elevated mixed layer (EML) (e.g., Carlson et al. 1983). LR36 represents a height-based alternative to the more widely used 700-500 hPa lapse rate.

BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

Lapse rate is defined as the temperature at the bottom of the layer minus the temperature at the top of the layer, divided by the layer depth. Positive LR thus indicates decreasing temperatures with height across the layer.

LR75

700 to 500 hPa Lapse Rate (K m-1)

The 700-500 hPa lapse rate (LR75) is defined as the difference in temperature between 700 and 500 hPa divided by the layer depth. Large values of LR75 may be favourable for thunderstorms and severe weather as they will promote larger CAPE and stronger convective updrafts. They can also indicate the presence of an elevated mixed layer (EML) (e.g., Carlson et al. 1983). LR75 is a component of the significant hail parameter (SHIP), a diagnostic developed in the US for forecasting large hail (Storm Prediction Center, 2024c). It is also a component of the SHERB (severe hazards in environments of reduced buoyancy) parameter, a diagnostic developed in the US for forecasting severe weather in high-shear, low-CAPE environments (Sherburn and Parker 2014).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

Lapse rate is defined as the temperature at the bottom of the layer minus the temperature at the top of the layer, divided by the layer depth. Positive LR thus indicates decreasing temperatures with height across the layer.

MAUL* (MAULbase, MAULdepth, MAULlapse)

Height AGL of Base of Moist Absolutely Unstable Layer (m)

A MAUL is a saturated layer featuring lapse rates steeper than the local pseudoadiabatic lapse rate, such that the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) decreases with height. MAULs occur when slab lifting of a conditionally unstable layer leads to saturation throughout the layer. While absolute instability would suggest rapid overturning and stabilisation, a MAUL can be maintained if the driving ascent is stronger than the resulting buoyant accelerations. MAULs have previously been identified in the inflow region of mesoscale convective systems (Bryan and Fritsch 2000), in tropical cyclones (Ross et al. 2004), and along narrow cold-frontal rainbands (Gatzen 2010). They have also been linked to the occurrence of rainfall extremes in the UK (Davies et al. 2024).

BARRA-R2/AUST-11/1hr

Following Bryan and Fritsch (2000), MAULs are identified as contiguous layers, at least 500 m in depth, where the wet-bulb potential temperature decreases with height and the dewpoint depression is less than 1°C. The base of the layer must be below the -1 degC level. In the case of multiple MAULs within a single profile, only the deepest one is retained.

MLCAP* (MLCAPbase, MLCAPdepth)

Height AGL of Base of Capping Layer for Mixed-Layer Parcel (m)

In profiles that feature two or more free convective layers (FCLs), the capping layer or "cap" is defined as the layer from the equilibrium level for the first FCL (EL1) to the level of free convection for the FCL with maximum CAPE (LFCx). The height of LFCx is given by CAPEbase + CAPdepth.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCAPE

Convective Available Potential Energy for Mixed-Layer Parcel (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur. MLCAPE is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCAPE03

Convective Available Potential Energy in 0 to 3 km AGL Layer for Mixed-Layer Parcel (J kg-1)

0-3 km mixed-layer convective available potential energy (MLCAPE03) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and 3 km above ground level (AGL). Large values of MLCAPE03 have been linked to an enhanced risk of tornadoes (e.g., Rasmussen 2003; Taszarek et al. 2020), including those not associated with supercell storms (Carusco and Davies 2005). MLCAPE03 is a component of the enhanced stretching potential (ESP), a diagnostic developed in the US for forecasting tornadoes (Storm Prediction Center, 2024b).

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCAPEx

Convective Available Potential Energy in Maximum-CAPE Layer for Mixed-Layer Parcel (J kg-1)

CAPEx is defined as the maximum convective available potential energy (CAPE) across all free-convective layers (FCLs). In profiles where only a single FCL exists, CAPEx = CAPE. In profiles featuring multiple FCLs, CAPEx represents the portion of the total CAPE that resides above the capping layer or "cap". The amount of CAPE that resides below (and within) the cap is given by CAPE - CAPEx.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCIN

Convective Inhibition for Mixed-Layer Parcel (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. MLCIN is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the tornado classifier for the ProbSevere nowcasting system (Cintineo et al. 2020). Note that MLCIN is undefined (NaN) where MLCAPE = 0.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCIN1

Convective Inhibition up to First Free Convective Layer for Mixed-Layer Parcel (J kg-1)

CIN1 is defined as the convective inhibition (CIN) that resides below the first free convective layer (FCL). In profiles where only a single FCL exists, CIN1 = CIN. In profiles featuring multiple FCLs, CIN1 represents the portion of the total CIN that resides below the capping layer or "cap". The amount of CIN within the cap is given by CIN - CIN1. Note that MLCIN1 is undefined (NaN) where MLCAPE = 0.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLEL

Equilibrium Level Height AGL for Mixed-Layer Parcel (m)

The equilibrium level (EL) is defined as the level at which a saturated and positively buoyant parcel becomes negatively buoyant. It represents the top of the free convective layer (FCL). In profiles featuring multiple FCLs, the EL of the FCL with maximum CAPE is used. The EL can be used as a proxy for convective cloud top. All else being equal, a higher EL is associated with larger CAPE, suggesting conditions more favourable for thunderstorms and severe weather. MLEL is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a). Note that MLEL is undefined (NaN) where MLCAPE = 0.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLCL

Lifting Condensation Level Height AGL for Mixed-Layer Parcel (m)

The lifting condensation level (LCL) is defined as the level at which an adiabatically lifted parcel becomes saturated. It can be used as a proxy for convective cloud base. A higher LCL is generally less favourable for tornadoes but more favourable for downdraft-driven severe windstorms such as downbursts and derechos. MLLCL is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the Additive Regression Convective Hazard Model (AR-CHaMo) for very large hail (Battaglioli et al. 2023).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLFC

Level of Free Convection Height AGL for Mixed-Layer Parcel (m)

The level of free convection (LFC) is defined as the level at which a saturated parcel becomes positively buoyant. It represents the base of the free convective layer (FCL). In profiles featuring multiple FCLs, the LFC of the first FCL is used. For parcels that are positively buoyant at the LCL, the LFC is set equal to the LCL. All else being equal, a higher LFC is associated with smaller CAPE and larger CIN, suggesting conditions less favourable for thunderstorms and severe weather. Note that MLLFC is undefined (NaN) where MLCAPE = 0.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLMB

Level of Maximum Buoyancy Height AGL for Mixed-Layer Parcel (m)

The level of maximum buoyancy (LMB) is defined as the level at which the buoyancy of a saturated parcel is maximised. All else being equal, a lower LMB will cause a parcel to accelerate more rapidly as it ascends above its level of free convection (LFC), promoting a stronger updraft at lower levels. Note that MLLMB is undefined (NaN) where MLCAPE = 0.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLPLmixr

Lifted Parcel Level Mixing Ratio of Mixed-Layer Parcel (kg kg-1)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MLLPL is defined as the lowest model level, but the thermodynamic properties of the parcel are determined by averaging over the lowest 500 m. The MLLPL parcel mixing ratio (MLLPLmixr) can be used in combination with the MLLPL pressure (MLLPLpres) and parcel temperature (MLLPLtemp) to calculate the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) of the ML parcel, both of which are conserved during its ascent. MLLPLmixr is used as a predictor in the Additive Regression Convective Hazard Models (AR-CHaMo) for large and very large hail (Battaglioli et al. 2023).

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLPLtemp

Lifted Parcel Level Temperature of Mixed-Layer Parcel (K)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MLLPL is defined as the lowest model level, but the thermodynamic properties of the parcel are determined by averaging over the lowest 500 m. The MLLPL parcel temperature (MLLPLtemp) can be used in combination with the MLLPL pressure (MLLPLpres) and parcel mixing ratio (MLLPLmixr) to calculate the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) of the ML parcel, both of which are conserved during its ascent.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLSCLR

Sub-Cloud Layer Lapse Rate for Mixed-Layer Parcel (K m-1)

The sub-cloud layer lapse rate (SCLR) is defined as the lapse rate between the surface and the lifting condensation level (LCL). Larger SCLR will promote a more rapid decrease in buoyancy for parcels descending below cloud base, favouring stronger downdrafts and associated severe winds.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLSCRHmean

Sub-Cloud Layer Mean Relative Humidity for Mixed-Layer Parcel (%)

The sub-cloud layer mean relative humidity (SCRHmean) is defined as the mean relative humidity between the surface and the lifting condensation level (LCL). Lower SCRHmean suggests enhanced potential for evaporatively driven cooling for parcels descending below cloud base, favouring stronger downdrafts and associated severe winds.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLVTEmax

Maximum Virtual Temperature Excess for Mixed-Layer Parcel (K)

Maximum virtual temperature excess (VTE) is defined as the maximum difference in virtual temperature between a lifted parcel and its environment above the lifting condensation level (LCL). It provides a measure of the maximum buoyancy of an ascending parcel and can be used to diagnose "fat" or "skinny" CAPE profiles (Blanchard 1998).

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLVTEmean

Mean Virtual Temperature Excess for Mixed-Layer Parcel (K)

Mean virtual temperature excess (VTE) is defined as the average difference in virtual temperature between a lifted parcel and its environment across all layers of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of the mean buoyancy of an ascending parcel and can be used to diagnose "fat" or "skinny" CAPE profiles (Blanchard 1998). Note that MLVTEmean is undefined (NaN) where MLCAPE = 0.

BARRA-R2/AUST-11/1hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCAPE

Convective Available Potential Energy for Most-Unstable Parcel (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur. MUCAPE is a component of the supercell composite parameter (SCP), a diagnostic developed in the US for forecasting supercell thunderstorms (Thompson et al. 2003, 2007; Gropp and Davenport 2018). It is also used as a predictor in the severe wind classifier for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCAPE0m20

Convective Available Potential Energy in 0 to -20 degC Layer for Most-Unstable Parcel (J kg-1)

Convective available potential energy (CAPE) in the layer from 0 degC to -20 degC is defined as the vertical integral of positive buoyancy between (i ) the level of free convection (LFC) or the 0 degC level (whichever is higher) and (ii) the equilibrium level (EL) or the -20 degC level (whichever is lower). It measures conditional instability within the charge reversal zone (CRZ; Bright et al. 2005). MUCAPE0m20 is a component of the cloud physics thunder parameter (CPTP), a diagnostic developed in the US for forecasting thunderstorms (Bright et al. 2005).

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCAPEm10m30

Convective Available Potential Energy in -10 to -30 degC Layer for Most-Unstable Parcel (J kg-1)

Convective available potential energy (CAPE) in the layer from -10 to -30 degC is defined as the vertical integral of positive buoyancy between (i ) the level of free convection (LFC) or the -10 degC level (whichever is higher) and (ii) the equilibrium level (EL) or the -30 degC level (whichever is lower). It measures conditional instability within the hail growth zone (HGZ) (Johnson and Sugden 2014). MUCAPEm10m30 is used as a predictor in the severe hail classifier for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCIN

Convective Inhibition for Most-Unstable Parcel (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. MUCIN is a component of the CIN-scaled supercell composite parameter (SCP), a diagnostic developed in the US for forecasting supercell thunderstorms (Gropp and Davenport 2018). Note that MUCIN is undefined (NaN) where MUCAPE = 0.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUEL

Equilibrium Level Height AGL for Most-Unstable Parcel (m)

The equilibrium level (EL) is defined as the level at which a saturated and positively buoyant parcel becomes negatively buoyant. It represents the top of the free convective layer (FCL). In profiles featuring multiple FCLs, the EL of the FCL with maximum CAPE is used. The EL can be used as a proxy for convective cloud top. All else being equal, a higher EL is associated with larger CAPE, suggesting conditions more favourable for thunderstorms and severe weather. MUEL is a component of the significant hail parameter (SHIP), a diagnostic developed in the US for forecasting large hail (Storm Prediction Center, 2024c). Note that MUEL is undefined (NaN) where MUCAPE = 0.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUELtemp

Equilibrium Level Temperature of Most-Unstable Parcel (K)

The equilibrium level (EL) is defined as the level at which a saturated and positively buoyant parcel becomes negatively buoyant. It represents the top of the free convective layer (FCL). In profiles featuring multiple FCLs, the EL of the FCL with maximum CAPE is used. The EL can be used as a proxy for convective cloud top. All else being equal, a higher EL is associated with larger CAPE, suggesting conditions more favourable for thunderstorms and severe weather. ELtemp is the parcel temperature at the EL. MUELtemp is a component of the cloud physics thunder parameter (CPTP), a diagnostic developed in the US for forecasting thunderstorms (Bright et al. 2005). Note that MUELtemp is undefined (NaN) where MUCAPE = 0.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULCL

Lifting Condensation Level Height AGL for Most-Unstable Parcel (m)

The lifting condensation level (LCL) is defined as the level at which an adiabatically lifted parcel becomes saturated. It can be used as a proxy for convective cloud base. All else being equal, a higher LCL (higher cloud base) is generally less favourable for tornadoes but more favourable for downdraft-driven severe windstorms such as downbursts and derechos.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULCLtemp

Lifting Condensation Level Temperature of Most-Unstable Parcel (K)

The lifting condensation level (LCL) is defined as the level at which an adiabatically lifted parcel becomes saturated. It can be used as a proxy for convective cloud base. LCLtemp is the parcel temperature at the LCL. MULCLtemp is a component of the cloud physics thunder parameter (CPTP), a diagnostic developed in the US for forecasting thunderstorms (Bright et al. 2005). Note that MULCLtemp is undefined (NaN) where MUCAPE = 0.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULFC

Level of Free Convection Height AGL for Most-Unstable Parcel (m)

The level of free convection (LFC) is defined as the level at which a saturated parcel becomes positively buoyant. It represents the base of the free convective layer (FCL). In profiles featuring multiple FCLs, the LFC of the first FCL is used. For parcels that are positively buoyant at the LCL, the LFC is set equal to the LCL. All else being equal, a higher LFC is associated with smaller CAPE and larger CIN, suggesting conditions less favourable for thunderstorms and severe weather. Note that MULFC is undefined (NaN) where MUCAPE = 0.

BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULMB

Level of Maximum Buoyancy Height AGL for Most-Unstable Parcel (m)

The level of maximum buoyancy (LMB) is defined as the level at which the virtual temperature excess of a saturated and positively buoyant parcel is maximised. All else being equal, a lower LMB will cause a parcel to accelerate more rapidly as it ascends above its level of free convection (LFC), leading to a stronger updraft at lower levels. Note that MULMB is undefined where MUCAPE = 0.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULPL

Lifted Parcel Level Height AGL for Most-Unstable Parcel (m)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MULPL is defined as the level that maximises convective available potential energy (CAPE). If the MULPL is above the boundary-layer top, this suggests that the environment is more favourable for elevated thunderstorms (particularly if the most unstable CAPE is much larger than the surface-based CAPE).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULPLmixr

Lifted Parcel Level Mixing Ratio of Most-Unstable Parcel (kg kg-1)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MULPL is defined as the level that maximises convective available potential energy (CAPE). The MULPL parcel mixing ratio (MULPLmixr) can be used in combination with the MULPL pressure (MULPLpres) and parcel temperature (MULPLtemp) to calculate the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) of the MU parcel, both of which are conserved during its ascent. MULPLmixr is a component of the significant hail parameter (SHIP), a diagnostic developed in the US for forecasting large hail (Storm Prediction Center, 2024c). It is also used as a predictor in the Additive Regression Convective Hazard Model (AR-CHaMo) for lightning (Battaglioli et al. 2023).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULPLpres

Lifted Parcel Level Pressure for Most-Unstable Parcel (Pa)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MULPL is defined as the level that maximises convective available potential energy (CAPE). The MULPL pressure (MULPLpres) can be used in combination with the MULPL parcel temperature (MULPLtemp) and parcel mixing ratio (MULPLmixr) to calculate the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) of the MU parcel, both of which are conserved during its ascent.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MULPLtemp

Lifted Parcel Level Temperature of Most-Unstable Parcel (K)

The lifted parcel level (LPL) is the level from which a parcel ascent is initialised. The MULPL is defined as the level that maximises convective available potential energy (CAPE). The MULPL parcel temperature (MULPLtemp) can be used in combination with the MULPL pressure (LPLpres) and parcel mixing ratio (MULPLmixr) to calculate the pseudo-equivalent potential temperature (e.g., Bolton 1980) or wet-bulb potential temperature (e.g., Davies-Jones 2008) of the MU parcel, both of which are conserved during its ascent.

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUVTEm10

Virtual Temperature Excess at -10 degC Level for Most-Unstable Parcel (K)

The virtual temperature excess (VTE) at -10 degC is defined as the difference in virtual temperature between a lifted parcel and its environment at the -10 degC level. It provides a measure of parcel buoyancy within the charge reversal zone (CRZ) (Bright et al. 2005) and may be a complementary diagnostic to the CAPE from 0 to -20 degC (CAPE0m20). Note that MUVTEm10 is undefined (NaN) where the lowest model level temperature is below -10 degC.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUVTEm20

Virtual Temperature Excess at -20 degC Level for Most-Unstable Parcel (K)

The virtual temperature excess (VTE) at -20 degC is defined as the difference in virtual temperature between a lifted parcel and its environment at the -20 degC level. It provides a measure of parcel buoyancy within the hail growth zone (HGZ) (Johnson and Sugden 2014) and may be a complementary diagnostic to the CAPE from -10 to -30 degC (CAPEm10m30). Note that MUVTEm20 is undefined (NaN) where the lowest model level temperature is below -20 degC.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUVTEmax

Maximum Virtual Temperature Excess for Most-Unstable Parcel (K)

Maximum virtual temperature excess (VTE) is defined as the maximum difference in virtual temperature between a lifted parcel and its environment above the lifting condensation level (LCL). It provides a measure of the maximum buoyancy of an ascending parcel and can be used to diagnose "fat" or "skinny" CAPE profiles (Blanchard 1998).

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUVTEmean

Mean Virtual Temperature Excess for Most-Unstable Parcel (K)

Mean virtual temperature excess (VTE) is defined as the average difference in virtual temperature between a lifted parcel and its environment across all layers of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of the mean buoyancy of an ascending parcel and can be used to diagnose "fat" or "skinny" CAPE profiles (Blanchard 1998). Note that MUVTEmean is undefined (NaN) where MUCAPE = 0.

BARRA-R2/AUST-11/1hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

PW

Precipitable Water (kg m-2)

Precipitable water (PW), also known as total precipitable water (TPW), column water vapour (CWV), and integrated water vapour (IWV), is defined as the column integral of water vapour density. It measures the amount of local atmospheric moisture available for cloud and precipitation formation. Anomalously high values of PW have been linked to extreme rainfall in many parts of the world, including Australia (e.g., Warren et al. 2021; White et al. 2021).

BARRA-R2/AUST-11/1hr

PW is computed as the integral of the product of specific humidity and air density between the lowest model level and 300 hPa.

RH01mean

0 to 1 km AGL Mean Relative Humidity (%)

The 0-1 km mean relative humidity (RH01mean) is defined as the average relative humidity between the surface and 1 km above ground level (AGL). Larger RH01mean will typically be associated with a lower surface-based or mixed-layer lifting condensation level (LCL) and reduced potential for evaporatively driven cooling below cloud base. High values of RH01mean are considered favourable for tornadoes (e.g., Thompson et al. 2003), whereas low values of RH01mean may be more favourable for cold pool-driven severe convective wind gusts. RH01mean can be used in combination with the 0-3 km mean relative humidity (RH03mean) to calculate the 1-3 km mean relative humidity.

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

RH03mean

0 to 3 km AGL Mean Relative Humidity (%)

The 0-3 km mean relative humidity (RH03mean) is defined as the average relative humidity between the surface and 3 km above ground level (AGL). Larger RH03mean will typically be associated with a lower surface-based or mixed-layer lifting condensation level (LCL) and reduced potential for evaporatively driven cooling below cloud base. Low values of RH03mean may be more favourable for cold pool-driven severe convective wind gusts. RH03mean can be used in combination with the 0-1 km mean relative humidity (RH01mean) to calculate the 1-3 km mean relative humidity.

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

RH24mean

2 to 4 km AGL Mean Relative Humidity (%)

The 2-4 km mean relative humidity (RH24mean) is defined as the average relative humidity between 2 and 4 km above ground level (AGL). Low values of RH24mean may be less favourable for thunderstorm development, due to enhanced entrainment-driven dilution of growing convective updrafts. However, when accompanied by steep lapse rates (large LR24) they may indicate the presence of an elevated mixed layer (EML) (e.g., Carlson et al. 1983).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

RH36mean

3 to 6 km AGL Mean Relative Humidity (%)

The 3-6 km mean relative humidity (RH36mean) is defined as the average relative humidity between 3 and 6 km above ground level (AGL). Low values of RH36mean may be less favourable for thunderstorm development, due to enhanced entrainment-driven dilution of growing convective updrafts. However, when accompanied by steep lapse rates (large LR36) they may indicate the presence of an elevated mixed layer (EML), (e.g., Carlson et al. 1983).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

SF

Saturation Fraction (%)

Saturation fraction (SF) is defined as the ratio of precipitable water (PW; the column integral of water vapour density) to saturation precipitable water (SPW; the column integral of water vapour density assuming saturation). It provides a measure of the average relative humidity of the column and thus is sometimes referred to as column relative humidity (CRH). SF shows a strong non-linear relationship with daily mean precipitation in the tropics (e.g., Bretherton et al. 2004) and has been found to discriminate well between ordinary, heavy, and extreme rainfall events in southeast Australia (Warren et al. 2021).

BARRA-R2/AUST-11/1hr

PW is computed as the integral of the product of specific humidity and air density between the lowest model level and 300 hPa. SPW is computed in an analogous manner but using the saturation specific humidity.

SRH01* (SRH01l, SRH01r)

0 to 1 km AGL Storm-Relative Helicity for Bunkers Left Mover (m2 s-2)

Storm-relative helicity (SRH) is defined as the vertical integral of the dot product of the storm-relative wind and streamwise vorticity vectors over a given layer. It provides a measure of the potential for updraft rotation and is thus a useful diagnostic for supercell thunderstorms and their associated hazards, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). The 0-1 km SRH (SRH01) is a component of the original fixed-layer significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003). It is also used as a predictor in the tornado classifier for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr

SRH is calculated using Eq. 8.15 from Markowski and Richardson (2010). The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted 0-8 km mean wind. The lowest model level is used in place of 0 km AGL.

SRH03* (SRH03l, SRH03r)

0 to 3 km AGL Storm-Relative Helicity for Bunkers Left Mover (m2 s-2)

Storm-relative helicity (SRH) is defined as the vertical integral of the dot product of the storm-relative wind and streamwise vorticity vectors over a given layer. It provides a measure of the potential for updraft rotation and is thus a useful diagnostic for supercell thunderstorms and their associated hazards, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). The 0-3 km SRH (SRH03) is a component of the original fixed-layer supercell composite parameter (SCP), a diagnostic developed in the US for forecasting supercell thunderstorms (Thompson et al. 2003).

BARRA-C2/AUST-04/1hr, BARRA-R2/AUST-11/1hr, BARRA-RE2/AUST-22/3hr

SRH is calculated using Eq. 8.15 from Markowski and Richardson (2010). The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted 0-8 km mean wind. The lowest model level is used in place of 0 km AGL.

SRH0500* (SRH0500l, SRH0500r)

0 to 500 m AGL Storm-Relative Helicity for Bunkers Left Mover (m2 s-2)

Storm-relative helicity (SRH) is defined as the vertical integral of the dot product of the storm-relative wind and streamwise vorticity vectors over a given layer. It provides a measure of the potential for updraft rotation and is thus a useful diagnostic for supercell thunderstorms and their associated hazards, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). The 0-500 m SRH (SRH0500) has been found to be a strong predictor of tornadoes (Coffer et al. 2019) and has been proposed as a replacement for 0-1 km or effective SRH in the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007).

BARRA-R2/AUST-11/1hr

SRH is calculated using Eq. 8.15 from Markowski and Richardson (2010). The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted 0-8 km mean wind. The lowest model level is used in place of 0 km AGL.

U01mean

0 to 1 km AGL Mean Eastward Wind (m s-1)

The 0-1 km mean wind is defined as the average wind velocity between the surface and 1 km above ground level (AGL). The 0-1 km mean wind can be combined with 0-3 km mean wind to calculate the 1-3 km mean wind, which is used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

U03mean

0 to 3 km AGL Mean Eastward Wind (m s-1)

The 0-3 km mean wind is defined as the average wind velocity between the surface and 3 km above ground level (AGL). The magnitude of the 0-3 km mean wind is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a). The 0-3 km mean wind can be combined with the 0-1 km mean wind to calculate the 1-3 km mean wind, which is used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

U0500mean

0 to 500 m AGL Mean Eastward Wind (m s-1)

The 0-500 m mean wind is defined as the average wind velocity between the surface and 500 m above ground level (AGL).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

U06mean

0 to 6 km AGL Mean Eastward Wind (m s-1)

The 0-6 km mean wind is defined as the average wind velocity between the surface and 6 km above ground level (AGL). The magnitude of the 0-6 km mean wind is a component of the derecho composite parameter (DCP), a diagnostic developed in the US for forecasting cold pool-driven severe convective windstorms (Storm Prediction Center, 2024a). The 0-6 km mean wind is also used as the advective component of storm motion in the original Bunkers method for estimating supercell storm motion (Bunkers et al. 2000).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

UANVmean

Anvil Layer Mean Eastward Wind (m s-1)

The anvil-level mean wind is defined as the average eastward wind velocity in the 1.5 km below the most unstable equilibrium level (MUEL). The angle between the 3-6 km and anvil-level mean winds is a component of the large hail parameter (LHP), a diagnostic developed in the US for forecasting hail greater than 2 inches (~5 cm) in diameter (Johnson and Sugden 2014). Observations also suggest a link between anvil-level storm-relative winds and supercell morphology (Rasmussen and Straka 1998), although this is not supported by more recent idealised modelling (Warren et al. 2017).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

UEILmean

Effective Inflow Layer Mean Eastward Wind (m s-1)

The effective inflow layer (EIL) mean wind is defined as the average wind velocity between the EIL base and EIL top.

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

UESMadv

Eastward Component of Effective-Layer Advective Storm Motion (m s-1)

The effective-layer advective storm motion is defined as the pressure-weighted mean wind between the effective inflow layer (EIL) base and 65 % of the most unstable equilibrium level (MUEL; Bunkers et al. 2014). It can be combined with the deviant storm motion to calculate the effective-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000, 2014). These estimates of storm motion can then be used in combination with low-level (e.g., 0-1 km) or EIL mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b). Note that UESMadv is undefined where the EIL is undefined.

BARRA-R2/AUST-11/1hr

USMadv

Eastward Component of Fixed-Layer Advective Storm Motion (m s-1)

The fixed-layer advective storm motion is defined as the pressure-weighted mean wind between the surface and 8 km above ground level (Bunkers et al. 2014). It can be combined with the deviant storm motion to calculate the fixed-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000). These estimates of storm motion can then be used in combination with low-level (e.g., 0-1 km) or effective inflow layer (EIL) mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b).

BARRA-R2/AUST-11/1hr

USMdev

Eastward Component of Deviant Storm Motion (m s-1)

The deviant storm motion is defined as a vector of magnitude 7.5 m/s that is perpendicular to the shear between the 0-500 m and 5.5-6 km mean winds (Bunkers et al. 2000). It can be combined with the fixed- or effective-layer advective storm motion to calculate the fixed- or effective-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000; 2014). These estimates of storm motion can then be used in combination with low-level (e.g., 0 to 1 km) or effective inflow layer (EIL) mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b).

BARRA-R2/AUST-11/1hr

V01mean

0 to 1 km AGL Mean Northward Wind (m s-1)

The 0-1 km mean wind is defined as the average wind velocity between the surface and 1 km above ground level (AGL). The 0-1 km mean wind can be combined with 0-3 km mean wind to calculate the 1-3 km mean wind, which is used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

V03mean

0 to 3 km AGL Mean Northward Wind (m s-1)

The 0-3 km mean wind is defined as the average wind velocity between the surface and 3 km above ground level (AGL). The magnitude of the 0-3 km mean wind is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a). The 0-3 km mean wind can be combined with the 0-1 km mean wind to calculate the 1-3 km mean wind, which is used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

V0500mean

0 to 500 m AGL Mean Northward Wind (m s-1)

The 0-500 m mean wind is defined as the average wind velocity between the surface and 500 m above ground level (AGL).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

V06mean

0 to 6 km AGL Mean Northward Wind (m s-1)

The 0-6 km mean wind is defined as the average wind velocity between the surface and 6 km above ground level (AGL). The magnitude of the 0-6 km mean wind is a component of the derecho composite parameter (DCP), a diagnostic developed in the US for forecasting cold pool-driven severe convective windstorms (Storm Prediction Center, 2024a). The 0-6 km mean wind is also used as the advective component of storm motion in the original Bunkers method for estimating supercell storm motion (Bunkers et al. 2000).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean. The lowest model level is used in place of 0 km AGL.

VANVmean

Anvil Layer Mean Northward Wind (m s-1)

The anvil-level mean wind is defined as the average eastward wind velocity in the 1.5 km below the most unstable equilibrium level (MUEL). The angle between the 3-6 km and anvil-level mean winds is a component of the large hail parameter (LHP), a diagnostic developed in the US for forecasting hail greater than 2 inches (~5 cm) in diameter (Johnson and Sugden 2014). Observations also suggest a link between anvil-level storm-relative winds and supercell morphology (Rasmussen and Straka 1998), although this is not supported by more recent idealised modelling (Warren et al. 2017).

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

VEILmean

Effective Inflow Layer Mean Northward Wind (m s-1)

The effective inflow layer (EIL) mean wind is defined as the average wind velocity between the EIL base and EIL top.

BARRA-R2/AUST-11/1hr

No pressure or density weighting is applied in the calculation of the layer mean.

VESMadv

Northward Component of Effective-Layer Advective Storm Motion (m s-1)

The effective-layer advective storm motion is defined as the pressure-weighted mean wind between the effective inflow layer (EIL) base and 65 % of the most unstable equilibrium level (MUEL; Bunkers et al. 2014). It can be combined with the deviant storm motion to calculate the effective-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000, 2014). These estimates of storm motion can then be used in combination with low-level (e.g., 0 to 1 km) or EIL mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b). Note that UESMadv is undefined where the EIL is undefined.

BARRA-R2/AUST-11/1hr

VSMadv

Northward Component of Fixed-Layer Advective Storm Motion (m s-1)

The fixed-layer advective storm motion is defined as the pressure-weighted mean wind between the surface and 8 km above ground level (Bunkers et al. 2014). It can be combined with the deviant storm motion to calculate the fixed-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000). These estimates of storm motion can then be used in combination with low-level (e.g., 0 to 1 km) or effective inflow layer (EIL) mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b).

BARRA-R2/AUST-11/1hr

VSMdev

Northward Component of Deviant Storm Motion (m s-1)

The deviant storm motion is defined as a vector of magnitude 7.5 m/s that is perpendicular to the shear between the 0-500 m and 5.5-6 km mean winds (Bunkers et al. 2000). It can be combined with the fixed- or effective-layer advective storm motion to calculate the fixed- or effective-layer Bunkers-left and Bunkers-right storm motion (Bunkers et al. 2000; 2014). These estimates of storm motion can then be used in combination with low-level (e.g., 0 to 1 km) or effective inflow layer (EIL) mean winds to calculate storm-relative inflow, which is a key control on updraft width, entrainment, and the potential for supercell storms (Droegemeier et al. 1993; Peters et al. 2019, 2020a,b).

BARRA-R2/AUST-11/1hr

WBFZL

Wet-Bulb Freezing Level Height AGL (m)

The wet-bulb freezing level (WBFZL) is defined as the height above ground level (AGL) at which the environmental wet-bulb temperature first drops below 0 degC. A higher WBFZL is indicative of a warmer and/or moister environment, which may be more favourable for thunderstorms but less favourable for hail (particularly small hail) due to enhanced melting. WBFZL is used as a predictor in the severe hail classifier for the ProbSevere nowcasting system (Cintineo et al. 2020). Note that WBFZL is undefined (NaN) where the wet-bulb temperature at the lowest model level is below 0 degC.

BARRA-R2/AUST-11/1hr