Effective as of 4:00 AM Monday May 3 2021
Explanatory notes:
Easterly gradient flow has strengthened with a west coast trough deepening near the west coast, this strong easterly gradient flow would keep the sea breeze suppressed today.
An upper level disturbance approaches from the west leading to some high and middle level cloud with some elevated convection possible late today, likely on Tuesday.
Some uncertainty on the details with regards to the timing and location of elevated thunderstorms, these sort of thunderstorms are very difficult to predict and can form at any time, but are especially likely from Tuesday afternoon with some surface based convection also possible if there is sufficient solar heating. It is also worth monitoring the severe threat given the steep vertical lapse rate and high vertical wind shear possible.
Once the upper level disturbance moves to the east most likely from early on Wednesday, thunderstorm chances diminishes, showers are still likely in the moist onshore flow on Wednesday.
During Thursday, another upper level trough and associated upper level cold pool approaches from the west bringing showers and possible thunderstorms.
Monday May 3:
City:
12-26 Degrees Celsius
Partly cloudy.
Chance of any rain:10%
Amount:Nil
Perth Metropolitan Area:
Partly cloudy.The slight chance of a shower or thunderstorm at night.Winds easterly at 20-30 km/h easing to 15-25 km/h in the afternoon.
Tuesday May 4:
City:
15-24 Degrees Celsius
Showers and thunderstorms.
Chance of any rain:90%
Amount:4 to 15 mm
Perth Metropolitan Area:
Partly to mostly cloudy.A very high (90%) chance of showers and thunderstorms.Winds northeasterly at 20-30 km/h becoming north-northeasterly at 10-25 km/h from afternoon.
Wednesday May 5:
City:
14-23 Degrees Celsius
Showers.
Chance of any rain:90%
Amount:2 to 8 mm
Perth Metropolitan Area:
Partly to mostly cloudy.A very high (90%) chance of showers.The chance of a thunderstorm early.Light winds becoming northwesterly at 10-20 km/h in the morning shifting west-southwesterly at 15-25 km/h in the afternoon becoming light at night.
Thursday May 6:
City:
13-21 Degrees Celsius
Showers.
Chance of any rain:90%
Amount:2 to 8 mm
Perth Metropolitan Area:
Partly to mostly cloudy.A very high(90%) chance of showers.The chance of a thunderstorm.Light winds.
Friday May 7:
City:
10-21 Degrees Celsius
Partly cloudy.
Chance of any rain:20%
Amount:Nil
Perth Metropolitan Area:
Partly cloudy.A slight(20%) chance of a shower.Winds east-southeasterly at 10-20 km/h tending south-southwesterly in the afternoon.