WA - SHOWERS RETURN TO THE AG AREAS FROM NEXT WEEK, A MILD AND SUNNY WEEKEND TO ENJOY BEFORE THEN.

OVERVIEW

High pressure, dry air and sinking air motion = dry weather through the weekend and into early next week for much of the inland, in fact some areas over the northern Ag Areas could see a lack of rainfall through 10 days.


Showers may return to the southwest and south with frontal weather glancing through a weak westerly wind regime offshore the coast.


The blocking pattern in the east is the key to how much of an impact the fronts will have on us here in the west. IF the pattern breaks down quicker, then the frontal weather will pack more of a punch than what the current guidance suggests.


SHORT TERM

The below average rainfall is expected to continue for much of the state as we track into the early part of next week. The showers coming through early next week will be light and patchy but the start of a few of them to impact the region next week.


The pattern as I see it, the fronts will gradually get stronger as we go along through the period. Stronger fronts bringing more rainfall to the SWLD will be found over the next weekend and into the second week of July with a colder and windier shift at this time.


LONG TERM

The east coast block is expected to move out by later next week and frontal weather which should be glancing through the southwest of the nation. That frontal weather will begin to track eastwards through the end of next week with stronger systems launching through WA then these look more likely to come across Southern Australia with more intensity as we track into the second week of July.


So once we lose the extensive rainfall over the north and east of the country, the weather is expected to return to more traditional conditions. Whether it can overcome the rainfall deficits over southern and Western Australia will be the question but right now it is unlikely.


AREAS TO WATCH

The SAM phase is important to watch over the coming week, if we see it head back into a negative phase then the frontal weather coming through in the second week of July could be very productive given the location of the wave action over the Southern Ocean.


The Indian Ocean is forecast to remain warmer than normal and this will feed moisture into the jet stream, whether it does it with the next wave of active frontal periods in the first part of July will be the issue, but most climate models support above average rainfall for July.


WEATHER VIDEO PM - THURSDAY 30TH JUNE 2022

FORECAST

Rainfall Next 10 Days

A big bag of nothing for many areas during the next 7-10 days with ridging and dry air in place. The best chances for rainfall will be found over the SWLD with a weak front moving through Monday into Tuesday before it clears. Another front glancing throughout the SWLD during Thursday before a stronger front passes through the SWLD with moderate to heavy falls next weekend with a strong cold front and colder shift. That front may tap into the moisture sitting well offshore the coast and a broad band of cloud and light to moderate rainfall may develop with that feature. Further frontal weather is possible into the second week of July for the SWLD with follow up rainfall.

Rainfall is expected to increase in freqeuncy over the southwest of the state with the widespread falls expected to move inland but the overall rainfall coverage is not expected to exceed the average and in fact may still be below average, but rainfall is likely to return in early July.

Still not expecting much through the interior for the coming 2 weeks.

MEDIUM TERM

July 8th - July 15th, 2022

Rainfall Anomalies

Relatively seasonal conditions forecast across most of the nation, though there are some increasing signals on the modelling, some quite aggressive, for rainfall being above average over the southeast and south of the country and possibly about the southwest. I would like to see more modelling on board for the higher rainfall chances to be extended into SA and NSW but right now I am not convinced of it.

Temperature Anomalies

There has been a shift towards a cooler bias across the nation in recent days and while I am seeing that colder bias, I am not confident on it being as cold as models suggest so keeping things milder over the east and southeast, cooler over the north and northwest and across western parts of the nation.

DATA - Refer to the video for further information.


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

As mentioned, there is so much going on in this active pattern and to cut down reading time, refer to the video at the top of the page.

00Z GFS - Precipitable Water Values - Next 2 Weeks

Moisture levels remain excessive along the east coast with some very heavy rainfall totals to develop for this time of year in response to that. The deeper moisture moving out of the NT, through QLD and into NSW and then remaining along the east coast, which is representative of the positive SAM phase. Overall, the pattern will breakdown mid next week, meaning that conditions along the west coast and through southern Australia will remain dry and settled under high pressure. Moisture will overcome the drier airmass over in the west by the end of next week, that moisture then spreading along the southern coastal areas bringing up the chances of rainfall for southern Australia once again and drier air moving back over the eastern and northern parts of the nation.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - rainfall is lean through the weekend and into next week but we do start to see moisture improving through the jet stream from later next week and into the following weekend with better signs for more traditional weather set to return with the moisture leading to higher rainfall chances. Whether it is enough to make up for the deficit caused by the recent weeks of dry remains to be seen.

More coming up from 8pm EST with a look at the models and rainfall.

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