SA - SHOWERS DEVELOPING FROM THE WEST THIS MORNING.

The start of another showery stretch for the southern and southeast districts with yet another onslaught of westerly winds and cooler weather to come. This will be a bleak week if you are living along the coast.


Note the system has started to stand up from yesterday where the cold air mass has consolidated into a low pressure system on the front. There is moisture surging southeast through the interior, denoted by the high cirrus and middle clouds. That may see some isolated showers form over the far northeast later today.


It is going to send in a cold airmass through southern SA with the colder air filtering east through Tuesday and Wednesday.


Farmers and Graziers Forecast next 3 days


Inland, things should begin to settle down with the wind easing over the region as high pressure begins to ridge in from the west, with settled skies and lighter winds, but underneath that ridge, the westerly winds will continue to bring cloudy skies and showers to the coastal areas, mainly east of Elliston.


The weather will greatly improve from Friday with a decrease in showers from the afternoon for the southeast.


The weekend, brighter, milder with temperatures near seasonal, and the chance of above average temperatures developing from Sunday ahead of the next front.


That front may bring another burst of showers to the west of the state this time next week, but model confidence is quite low.


Lets have a look at modelling


12Z GFS Surface Pressure Pattern for the coming 16 days

Rainfall is still anticipated to be the most widespread during the next 2 days with the final wave passing over. The weather will clear the inland areas from mid week and by the end of this week most of the state should have returned back to dry and clearer with a milder northwest flow. The weather looks good for the weekend, but another wave of frontal weather is expected to bring another batch of cold fronts to southern Australia with the rainfall not as extensive as this event running over the nation, however it is over a week out and will likely change. The high pressure belt is slowly moving south over the southern states during this period and may deflect the cold fronts further south than where they have been during recent weeks.

12z GFS Rainfall for the coming 10 days

No change from last night with the most widespread rainfall coming up today and through Wednesday for southern inland areas before it begins to clear southwards later this week ahead of a dry weekend. Then we are looking at more frontal weather developing next week through WA and SA with moisture streaming in ahead of these systems, there is a chance of further areas of rain/showers for southern NSW. But the north should remain dry for now.

12Z GFS Precipitable Water Values for the coming 16 days

Elevated PW values continue to surge southeast ahead of the front today with that helping to develop a cloud band with showers and thunderstorms developing. Then the PW values will come down as a dry southwest flow moves into the eastern inland. The moist air in the lower levels will persist over the inland leading to cloudy skies and light showers until about mid week and then drier and more stable air under high pressure clears the state from later this week into the weekend as the winds turn northwesterly. Another wave of tropical moisture coming from the Indian Ocean accompanies the next front passing over WA through SA next week and that needs watching if that brings another band of rainfall.

12z Euro Surface Pressure Pattern for the coming 10 days

The surface pressure pattern remains unchanged on the Euro for the coming few days, the last of the strong fronts passing through today and tomorrow bringing the most widespread rainfall and a shift to colder weather for the southeast states. The high over WA ridging in will move over much of the nation from mid to late week bringing clearance and a nice weekend of weather. Next week we have another wave of frontal weather to deal with however the frontal weather may be further south than this lot coming through this week, meaning that rainfall could be more coastal early next week. We have to watch the moisture streaming in on the northern flank of this wave as another band of rainfall may develop, as was the case on Saturday with 15-30mm falling over much of VIC.

12z Euro Rainfall for the coming 10 days

No change from last night, really good agreement and guidance on the rainfall over the coming 24 hours. The better rainfall will develop over the south this afternoon and then the southeast tonight through Tuesday morning with moderate falls possible .The rainfall then contracts back through to coastal areas with the winds turning southwesterly and stabalising. The weather turning clear for the inland areas from mid week and then statewide the skies brighter this weekend. That will be where the weather turns milder. Next we have another belt of rain likely to develop from the west but how widespread it is, is to be determined.

12Z Euro Precipitable Water Values for the next 10 days

You can see that Indian Ocean influence in the coming 2 days with the moisture streaming across the nation northwest to southeast. That will trigger more light to moderate inland rainfall. For coastal areas, the rainfall is connected to the frontal passage this week and again next week. Another burst of moisture rushing through the jet stream early next week may produce another band of rainfall for WA and SA in around about a week or so.

Rainfall for the next 10 days

Rainfall is largely unchanged for the coming 2 days, this is where the bulk of the rainfall will fall. Then light showers for coastal areas until Thursday may top up falls towards 25mm maybe a few higher accumulations. Next week, I am not drawing in the rainfall yet as the frontal weather is hard to pin down and it could be that the moisture coming out of the Indian Ocean may be forced southeast offshore the southern coast of the country if the high over the nation is stronger. We wait and see.

More weather coming today with a look at the follow up rainfall event possible with the moisture coming out of the Indian Ocean.


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