Effective as of 12:00 AM Thursday December 9 2021
View the latest severe weather warnings from BOM at http://www.bom.gov.au/wa/warnings/ .
Explanatory notes:
It was a very hot day yesterday with temperatures having reached 40.0°C at the official Mt Lawley site with the hot air mass over the region with the west coast trough deepening offshore.A weak sea breeze had developed over western suburbs.
The west coast trough is expected to move inland today bringing cooler but humid conditions once the onshore flow becomes established advecting the marine layer 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. It is expected to be very hot inland due to the later arrival of the onshore flow.
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.
Mostly sunny conditions thereafter as subtropical high pressure builds to the south. A weak cold front possibly brushes the southwest of the state on Tuesday or Wednesday bringing cooler conditions and the possibility of showers but still plenty of uncertainty this far out.
Thursday December 9:
City:
Partly cloudy.
Chance of any rain:5%
Amount:Nil
Perth Metropolitan Area:
Partly cloudy.Very hot inland.Winds northeasterly at 20-30 km/h shifting westerly at 15-25 km/h by afternoon, becoming southwesterly at 5 –15 km/h at night.
Friday December 10:
City:
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.