Getting ever so close now to the rainfall moving into southwest WA over the coming 24-36hrs, and with that a colder shift as well.

It has been a long time coming after a very hot April with temperatures being pretty much well above average most of this month.

GFS observed temperature anomalies for Monday 26th April 2021

GFS forecast temperature anomalies for Friday. Wind chill will be running very high.

However we are ending the month, well below average with rain and strong winds about. There is an outside risk of severe weather developing with damaging winds along the front as it rolls over the west coast. Also the temperature gradient between the hot air and the colder air moving into the region may bring up the wind strengths to gale force.

Perhaps an increase of thunderstorms and possible severe storms in the region. The limiting factor to this is little surface based instability. But the front itself could pack a punch.

Euro model 18z run for surface based instability showing values of around 200-500j/kg. That is sufficient for thunderstorms along the front - some could be severe with damaging winds.

Rainfall with this first front looks to be around 10-20mm for the SWLD with 5-10mm for the inland areas to the Wheatbelt.

But there is another front with the potential for a large plume of moisture coming in from the Indian Ocean which could bring another 10-30mm for the SWLD and 10-20mm over the inland to about the Wheatbelt and along the south coast. That looks to arrive next week.

GFS Rainfall accumulation 12z run shows a little less rainfall for the SWLD however look at the moisture sitting off the coast over the Indian Ocean and how that is picked up through parts of central WA. That will change but a signal of what COULD occur next week down this region.

Weather matters rainfall forecast for the next 10 days

More weather details to come as the system rolls through tomorrow and again next week. The system next week has a greater chance of producing heavier and more widespread rainfall.

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