Numerical Prediction Charts - Weather and Waves

The Bureau's National Meteorological and Oceanographic Centre (NMOC) runs numerical models over several geographic areas (domains) to provide automated analyses and predictions of atmosphere and ocean characteristics on a range of time-scales. These products are used as guidance for the Bureau's official forecasts. They can also be used independently, but it must be remembered that they are automated products which have not been checked by meteorologists.

Analysis charts are a snapshot of the weather situation at the base observation time (valid time), while prognosis charts are a forecast for the specified time, up to 7 days ahead.

Analysis charts are time-stamped in "UTC" (Coordinated Universal Time), which is equivalent to GMT (Greenwich Mean Time). This is the time when the observations on which the chart is based were taken. The issue time is normally around two hours after the time of the base observations.

Numerical model prognosis charts may be labelled with the time at which the forecast is valid or with a +12 hr, +24 hr, +36hr, +48 hr, +72 hr etc from the base observation time for that run of the model. Generally the models are run twice daily, with their initial analyses being at 00UTC and 12UTC.

A new suite of numerical weather and wave prediction models came into operation in June 2010. The new Australian Community Climate and Earth-System Simulator (ACCESS) weather models have been developed and tested by research staff from the Centre for Australian Weather and Climate Research (CAWCR) and are based on the UK Meteorological Office's Unified Model. The ACCESS suite of models has shown a significant improvement in accuracy over the Bureau's old weather model suite (GASP, LAPS and MesoLAPS), and is routinely generating a range of new weather charts and gridded data products.

The table below lists the geographic domains and grid-spacing (resolution) of the models in the operational ACCESS suite, and their equivalents in the old model suite. More detailed technical information on the ACCESS models is available in the NMOC Operations Bulletin No. 83.

ModelDomainResolutionPrevious model equivalent
ACCESS-G Global Approximately 80km Global Analysis and Prediction (GASP)
ACCESS-R Regional 0.11° (~12km) Limited Area Prediction System (LAPS_PT375)
ACCESS-T Tropical 0.375° (~37.5km) Tropical (Extended Domain) LAPS (TXLAPS_PT375)
ACCESS-A Australia 0.11° (~12km) MesoLAPS (MESO_LAPS_PT125 & MA_LAPS_PT100)
ACCESS-C+ City 0.05° (~5km) City-based MesoLAPS variants (MESO_LAPS_PT050 models)
ACCESS-TC Relocatable 0.11° (~12km) Tropical-cyclone LAPS (TCLAPS)
ACCESS-O3 Global Approximately 80km specialist model to replace the ozone and UV components of GASP
Note: ACCESS-C consists of a set of models covering domains around Sydney, Melbourne, Brisbane, Perth and Adelaide.

The domains used for the models can be seen in the diagram below.

Domain boundariesused by the models

Numerical predictions of ocean wave characteristics are now provided by the WAVEWATCH III model, originally developed by NOAA in the US and implemented operationally by CAWCR and NMOC. This model replaces the Bureau's WAM model, and is run on global, regional and Australia domains as used in ACCESS.

The charts generated by the ACCESS and WAVEWATCH models represent a variety of atmosphere and ocean characteristics at a number of elevations. The full suite of charts is listed in the tables below.

Upper air charts are generally labelled with the pressure level in hectopascals (hPa) e.g. 500 hPa. The pressure decreases upwards in the atmosphere e.g. the 250 hPa level is higher than the 500 hPa level. For some fields there are also charts representing the atmosphere 2 metres and 10 metres above the ground, and at the "gradient" level which lies about 1000 metres above the earth's surface and is the level most representative of the air flow in the lower atmosphere immediately above the layer affected by surface friction. This level is free of local wind and topographic effects (such as sea breezes, downslope winds etc).

Some charts show geopotential height, which approximates the actual height of a pressure surface above mean sea-level. Therefore, geopotential height contours on a particular map, e.g. 850 hPa, represent the height of that pressure surface.

Charts showing precipitation represent the amount of rainfall in millimetres which is forecast to fall at the ground over the preceding 3 or 6 hours. The period is shown in the chart heading as "3 hrly" or "6 hrly".

ACCESS Numerical Weather Prediction Charts

 ACCESS-GlobalACCESS-RegionalACCESS-Tropical ACCESS-AustraliaACCESS-CitiesACCESS-TCACCESS-O3
Typical Chart Availability Times: 0610Z (00Z run)
1810Z (12Z run)
0230Z (00Z)
0830Z (06Z)
1430Z (12Z)
2030Z (18Z)
0430Z (00Z)
1630Z (12Z)
0400Z (00Z)
1000Z (06Z)
1600Z (12Z)
2200Z (18Z)
Vic/Tas: 0310Z (00Z), 1510Z (12Z)
Syd, Bris, Adel, Per: 0300Z (00Z), 1500Z (12Z)
N/A 0700Z (00Z)
Domains: Global, SH, Aust Region, IO, Pacific Full Domain, Aust Region Full Domain, RSMC, Australia, SE Asia, SW Pacific, NT, WA, Fiji... (15 all up) Full Domain, Regional (7) 5 Cities 3 con-current Global, SH, Aust Region
Projections: Lat/Lon, Polar St, Lambert-Conformal Lat/Lon, Lambert-Conformal Lat/Lon, Polar St Lat/Lon, Lambert-Conformal Lat/Lon   Polar St, Lat/Lon
Timestep: 6 hourly (to +168) 3 hourly (to +72) 6 hourly (to +72) 3 hourly (to +48) 1 hourly (to +36)   6 hourly (to +168)
Single-Level Elements: Precipitation Precipitation Precipitation, Deep-layer mean wind Precipitation, Wind gust, Snow Precipitation, Meteograms Tracks UV Index, UV Index Cities, Total Ozone
Multi-level Elements: Wind: 10m, Gradient, 850, 700, 500, 200 Wind: 10m, Gradient, 850, 700, 500, 200 Wind: 10m, Gradient, 850, 700, 500, 200 Wind: 10m, Gradient, 850, 700, 500, 200 Wind: 2m, 10m, Gradient, 850    
      Vorticity: 900, 200        
  Pressure: MSLP, MSLP/THICK, MSLP/Precip Pressure: MSLP, MSLP/THICK, MSLP/Precip Pressure: MSLP, MSLP/THICK, MSLP/Precip Pressure: MSLP, MSLP/THICK, MSLP/Precip Pressure: MSLP    
  Geopotential Height: 850, 700, 500, 200 Geopotential Height: 850, 700, 500, 200 Geopotential Height: 850, 700, 500, 200 Geopotential Height: 850, 700, 500, 200      
  Temperature: 2m screen, 850, 700, 500, 200 Temperature: 2m screen, 850, 700, 500, 200 Temperature: 2m screen, 850, 700, 500, 200 Temperature: 2m screen, 850, 700, 500, 200      
  Td: 2m screen Td: 2m screen Td: 2m screen Td: 2m screen      
  RH: 2m screen, 850, 700, 500, 200 RH: 2m screen, 850, 700, 500, 200 RH: 2m screen, 850, 700, 500, 200 RH: 2m screen, 850, 700, 500, 200      
  Stability field, e.g. Total Totals OR Lifted Index            

WAVEWATCH III Wave Charts

 WWIII-GlobalWWIII-RegionalWWIII-Australia
Typical Chart Availability Times: 0700Z (00Z run)
1900Z (12Z run)
0300Z (00Z)
1500Z (12Z)
0400Z (00Z)
1000Z (06Z)
1600Z (12Z)
2200Z (18Z)
Domains: Global, SH, Aust Region, Pacific, IO, Casey (Antarctic) Aust Region Full Domain, NW, SW, SE, NE, Bass Strait
Projections Lat/Lon, Polar St Lat/Lon Lat/Lon
Timestep: 6 hourly to 168 hrs 6 hourly to 48 hrs 3 hourly to 48 hrs
Contour Fields Sig Wave Height/Direction,
1st Swell Compt+Dir,
2nd Swell Compt+Dir,
Wind Wave Height,
Peak Period,
Surface Wind
Sig Wave Height/Direction,
1st Swell Compt+Dir,
2nd Swell Compt+Dir,
Wind Wave Height,
Peak Period,
Surface Wind
Sig Wave Height/Direction,
1st Swell Compt+Dir,
2nd Swell Compt+Dir,
Wind Wave Height,
Peak Period,
Surface Wind