7 day weather forecast

Effective as of 12:00 AM Friday December 24 2021

View the latest severe weather warnings from BOM at http://www.bom.gov.au/wa/warnings/ .

Explanatory notes:

An unusually intense heatwave, arguably Perth's worst December heatwave on record occurs until Tuesday as a very hot air mass lies over the region with the west trough deepening and lying offshore for several days and an upper level high leading to subsidence heating of the airmass.At least 3 consecutive days with maximum temperatures above 40.0°C are expected.Perth's longest December 40+°C spell on record was 3 consecutive days in December 2019. Prior to December 2019, 3 consecutive 40+°C days was underheard of in December. 

Conditions would also be extremely bad in terms of bushfires with significant dry easterly winds expected. The easterlies would be particularly strong late tonight, early on Christmas day and again later at night on Christmas Day and early on boxing day where the strong easterly gradient combined with katabatic effect could lead to gusts in excess of 80 km/h over the hills and foothills. The strong easterly gradient with the west coast trough offshore will keep the sea breeze fairly weak, if it develops on Christmas and Boxing Day.

The most likely scenario is for the heatwave to end from next Wednesday as the west coast trough moves inland leading to earlier sea breeze onset and the marine layer advecing over the region.

Friday December 24:

City:

21-38  Degrees Celsius

Very hot and sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Very hot and sunny.Winds east-southeasterly at 15-25 km/h tending south-southwesterly at 20-30 km/h in the afternoon becoming east-southeasterly at 25-40 km/h at night.Gusts in excess of 75 km/h possible over the hills and foothills later at night.

Saturday December 25:

City:

22-43  Degrees Celsius

Very ho ho hot and sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Very hot and sunny.Winds easterly at 25-40 km/h becoming northeasterly at 20-30 km/h in the morning easing to 10-20 km/h in the afternoon with a south-southwsterly sea breeze at 10-20 km/h possible in the afternoon, becoming east-southeasterly at 20-35 km/h later at night.Gusts in excess of 80 km/h possible over the hills and foothills early and again later at night.

Sunday December 26:

City:

28-43  Degrees Celsius

Very hot and sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Very hot and sunny.Winds east-northeastery at 20-35 km/h becoming northeasterly at 20-30 km/h in the morning easing to 10-20 km/h in the afternoon, tending easterly in the late afternoon and evening increasing to 20-30 km/h later at night.Gusts in excess of 80 km/h possible over the hills and foothills early.

Monday December 27:

City:

27-41  Degrees Celsius

Very hot and mostly sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Very hot and mostly sunny.Winds northeasterly at 20-30 km/h tending southwestery at 15-25 km/h in the afternoon becoming light at night.

Tuesday December 28:

City:

24-39  Degrees Celsius

Very hot and mostly sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Very hot and mostly sunny.Winds northeasterly at 15-25 km/h shifting southwesterly by afternoon.

Wednesday December 29:

City:

22-35  Degrees Celsius

Mostly sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Mostly sunny.Winds southerly at 10-20 km/h tending southwesterly at 15-25 km/h in the afternoon.

Thursday December 30:

City:

19-32  Degrees Celsius

Mostly sunny.

Chance of any rain:0%

Amount:Nil

Perth Metropolitan Area:

Mostly sunny.Winds southerly at 10-20 km/h becoming south-southwesterly at 20-30 km/h in the afternoon.

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