The forecasts are produced by me using a wide variety of data including weather model predictions,surface observations,weather balloon(radiosonde) data,satellite data,Doppler radar data as well as synoptic charts,upper air charts and poor man and single model ensembles as well as the BOM Operational Consensus Forecast(OCF) and off course my knowledge and experience.
Weather models that I use include the ECMWF model,GFS,Access Global,ACCESS Regional,CMC,NAVGEM,UK Met Office and ICON and WRF.
The main players among weather models are the ECMWF,GFS,Access Global and Access Regional which are amongst the best models in the world.
Based on my experience with Perth and international statistics the ECMWF is the best weather model in the world on a wide variety of benchmarks.
My forecasts are typically produced everyday after around 3:30 PM.Sometimes unconventional updates are released.
This time was chosen as the forecast production time so that I will be able to utilize the 00Z runs of the weather models and ensembles as well as the the 06Z run of the BOM Poor Man Ensemble(PME) and BOM Operational Consensus Forecast(OCF).
The BOM PME provides reasonable guidance for chance of rain and rainfall amounts and the BOM OCF provides reasonable guidance on temperatures and is also heavy utilized by the BOM.
The forecasts are typed out and formatted manually by me where as at the BOM forecasters use a Graphical Forecast Editor to generate "weather forecast grids" stored in a database known as the Australian Digital Forecast Database(ADFD) and text products are automatically generated and weather icons automatically chosen by the Graphical Forecast Editor where forecasters can manually change if necessary.
I manually insert the weather icons which are typically sourced from thousands of weather icons used by the US National Weather Service.Some of the weather icons such as the weather icon for high clouds are produced by me.
Forecast terminology:
Time of day:
Cooler months(May 1-September 30):
Early hours:12AM-7AM
Morning:before 12PM
Middle of the day:11AM to 1PM
Afternoon:1PM to 5PM
Evening:5PM to 7PM
Night:After 6:30 PM.
Warmer months(October 1-April 31):
Early hours:12AM to 5:30 AM
Morning:before 12 PM
Middle of the day:11AM to 1PM
Afternoon:1PM to 6PM
Evening:6PM to 8PM
Night: After 7:30 PM
Time of day:
Cooler months(May 1-September 30):
Early hours:12AM-7AM
Morning:before 12PM
Middle of the day:11AM to 1PM
Afternoon:1PM to 5PM
Evening:5PM to 7PM
Night:After 6:30 PM.
Warmer months(October 1-April 31):
Early hours:12AM to 5:30 AM
Morning:before 12 PM
Middle of the day:11AM to 1PM
Afternoon:1PM to 6PM
Evening:6PM to 8PM
Night: After 7:30 PM
Cloud cover:
Sunny/clear:
Less than 10% of the sky obscured by clouds.
Less than 10% of the sky obscured by clouds.
Mostly sunny/mostly clear/a few clouds:
10% to 25% of the sky obscured by clouds.
10% to 25% of the sky obscured by clouds.
Partly cloudy/scattered clouds:
25% to 60% of the sky obscured by clouds.
25% to 60% of the sky obscured by clouds.
Mostly cloudy/broken clouds:
60% to 80% of the sky obscured by clouds.
60% to 80% of the sky obscured by clouds.
Cloudy:
More than 80% but less than 100% of the sky obscured by clouds.
More than 80% but less than 100% of the sky obscured by clouds.
Overcast:
100% of the sky obscured by clouds.
100% of the sky obscured by clouds.
Partly to mostly cloudy:
Periods of partly and mostly cloudy conditions.
Periods of partly and mostly cloudy conditions.
Cloudy to mostly cloudy:
Periods of cloudy and mostly cloudy conditions.
Periods of cloudy and mostly cloudy conditions.
High clouds:
Clouds with bases of at least 5030 meters/16500 feet in altitude above mean sea level.
Clouds with bases of at least 5030 meters/16500 feet in altitude above mean sea level.
Areal coverage:
Isolated/odd:10% to 25% of the area.
Scattered:25% to 50% of the area.
Widespread:More than 50% of the area.
Patchy(typically used for stratiform precipitation as well as fog,mist and frost):10% to 25% of the area.
Areas(typically used for stratiform precipitation as well as fog,mist and frost):25%% to 50% of the area.
