Effective as of 12:00 AM Wednesday December 8 2021
View the latest severe weather warnings from BOM at http://www.bom.gov.au/wa/warnings/ .
Explanatory notes:
A strong easterly gradient with the west coast trough offshore lead to strong and gusty easterlies with gusts having reached 80 km/h at Gooseberry Hills early on Tuesday. Winds eased Tuesday afternoon with increased vertical mixing and also the land being hotter than the sea. Winds strengthened again with gusts exceeding 80 km/h being once again possible over the hills and foothills as vertical mixing decreased as the land cooled down.
Also, the possibility of elevated convection today with instability aloft ahead of an upper level trough. Some altocumulus castellanus clouds were observed indicative of instability aloft with isolated elevated convective cells having already developed.
A very hot day today with the hot air mass over the region with the west coast trough depending offshore, maximum temperatures could exceed 40°C if skies are sufficiently clear.
The west coast trough likely moves inland on Thursday bringing cooler but humid conditions once the marine layer advects onshore. Maximum temperatures depend on how early the west coast trough moves inland. A later arrival of the onshore flow would lead to another very hot day.
The slight possibility of showers in the moist onshore flow on Friday and Saturday with a low pressure system to the south of the state.
Wednesday December 8:
City:
22-40 Degrees Celsius
Very hot and mostly sunny.
Chance of any rain:20%
Amount:Nil
Perth Metropolitan Area:
Very hot and mostly sunny.A slight(20%) chance of showers and/or thunderstorms most likely in the early hours and morning.Winds east-northeasterly at 25-40 km/h becoming northeasterly in the morning, easing to 10-20 km/h in the afternoon, increasing to east-northeasterly at 20-30 km/h later at night.Gusts in excess of 80 km/h possible over the hills and foothills early.
Thursday December 9:
City:
24-36 Degrees Celsius
Mostly sunny.
Chance of any rain:5%
Amount:Nil
Perth Metropolitan Area:
Mostly sunny.Very hot inland.Winds northeasterly at 20-30 km/h shifting westerly at 15-25 km/h by afternoon, becoming light at night.
Friday December 10:
City:
19-25 Degrees Celsius
Partly cloudy.
Chance of any rain:20%
Amount:Nil
Perth Metropolitan Area:
Partly cloudy.A slight(20%) chance of a shower.Winds west-southwesterly at 10-20 km/h increasing to southwesterly at 20-30 km/h in the morning.
Saturday December 11:
City:
17-25 Degrees Celsius
Possible shower.
Chance of any rain:30%
Amount:0 to 0.4 mm
Perth Metropolitan Area:
Partly cloudy.A slight(30%) chance of a shower.Winds southwesterly at 15-25 km/h becoming south-southwesterly from evening.
Sunday December 12:
City: