Effective as of 4:00 AM Monday May 24 2021
Explanatory notes:
Plenty of showers with the cold and unstable unstable air mass over the region with the possibility of small hail early. Showers enhanced by the land breeze convergence with the southwesterlies. Small hail chances decreases from morning with the depth of instability decreasing.
Despite the strong southwesterly gradient flow, winds will be light for much of the time until later in the morning due to boundary layer decoupling due to the pool of rain cooled air near the surface and cold air attempting to move down the hills. However, heavier showers moving from the showers could lead to strong southwesterlies from time to time, most likely near the coast.
Showers continue into the afternoon becoming lighter as depth of the instability decreases and showers clear by night with the development of a land breeze and the ridge of high pressure developing.
Cold morning on Tuesday, how cold is dependent on cloud cover, latest NWP guidance show more cloud cover compared to the guidance on Saturday, this cloud cover would limit how cold it gets. Another cold morning on Wednesday.
Becoming warm again with the high pressure system moving into the Great Australian Bight.
A cold front ahead of an upper level trough likely arrives from Friday bringing showers with the possibility of thunderstorms with instability but still some uncertainty on the details this far out.
Monday May 24:
Showers.
Chance of any rain:95%
Amount:3 to 10 mm
Perth Metropolitan Area:
Partly to mostly cloudy. A very high (95%) chance of showers clearing later in the afternoon.Light winds becoming south-southwesterly at 15-30 km/h from late morning becoming light at night.