SA - MOSTLY DRY FOR THE NEXT WEEK, RAIN POSSIBLE IN THE NORTHWEST. FRONTS APPROACHING NEXT WEEK.

The weather is forecast to remain dry and settled for the most part this week as a high-pressure belt is forecast to develop in the Bight leading to a clearing of the cloud and easing of southwest to westerly winds. The high-pressure system is forecast to then become slow moving while sitting over the Agricultural areas for the best part of the week.


Out over the northwest of the state, moisture is forecast to move through from WA with areas of rain and thunderstorms across inland areas of WA moving into the NW Pastoral district. In times when there is not high pressure, we usually see rainfall coming into the remainder of the state. But the high is forecast to be the dominate force and deflect the rainfall south and undermining the coverage of rainfall throughout the state.


So the dry weather will continue through the weekend and into next week with warmer weather evolving as northeast to northerly winds developing. The warmer weather kicking into the weekend and leading to well above average temperatures. We could see cloud increasing from mid next week as a frontal passage moves into the Bight. Moisture from the northwest flow aloft over interior parts of WA is forecast to move east and this is where we see the rainfall numbers coming up.


It is important to recognise that the rainfall forecast that far out is quite of low confidence but high confidence in the trend of moisture moving into a more favourable position for rainfall to evolve in the region during this time for the end of the month and as we move into June.


Let's take a look

FORECAST

Rainfall Next 10 Days

Rainfall is forecast to be limited to the southeast coastal areas during the coming 2 days with light falls. A high-pressure belt over the Bight helping to direct the onshore winds, this high is forecast to move over the Ag Areas by Wednesday with the strength of the ridge increasing. Over the western and northwestern interior there could be some rainfall spill over from inland WA with moderate to heavy falls possible with some thunderstorms about. With the high sitting over the state, the rainfall event will be weakened and likely see it fall apart by Thursday with dry weather taking us through to early next week statewide. The next rainfall event is forecast to develop from the west in about 9 days time with moisture and frontal weather combining to bring at-least some patchy rainfall to the state which will be welcome. Forecast amounts will become clearer as we get closer.

The bulk of the rainfall is expected towards the middle of next week so expect dry weather from now through to about Tuesday or Wednesday of next week, which will spread in from the west for Ag Areas. Moderate rainfall in the short-term stays trapped over in western and northwest SA.

Frost Risk Forecast - Tuesday through Friday

A drier airmass is forecast to settle in from Monday and with clearer skies and the high-pressure ridge moving in, there is the chance of frost developing. The peak of frost is forecast from Wednesday and Thursday before easing later this week.

DATA - Refer to video for more context on the weather conditions at play through this period.


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

There is more information contained to the video for you to review, the events to watch are the rainfall events over the west in the coming 2 days, the rain event along the QLD coast this weekend, does that move into NSW or stay further east? Then in the medium term, the rainfall focus seems to shift south through WA, to SA and into the southeast inland including VIC, southern NSW and the ACT. This could be the wettest weather via the westerly wind belt so far, this cool season for these areas.

00Z GFS - Precipitable Water Values - Next 2 Weeks

Moisture is being shunted northwards as expected today with a drier and cooler southwesterly flow over the east with ridging moving into the Bight. On the western flank of the high, there is warmer and more humid air leading to increasing rainfall chances throughout WA and that could come into the southwest NT and western SA. Moisture is forecast to increase over QLD and spread west bound, covering much of NSW and QLD throughout the weekend and into next week which is interesting. The overall trend is supportive of more rainfall in the eastern inland of the nation though I am not drawing that in yet but watch for further updates this evening and tomorrow morning. Then we see a more mobile pressure pattern with the westerly wind belt moving north, pushing the high-pressure belt further north, leading to colder and showery weather heading for southern Ag areas 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 - the moisture is increasing in this latest run of the GFS for the rainfall over the eastern inland of NSW and spreads the moisture west into eastern areas of the state this weekend, I am not so sure on that idea. But certainly, better odds for rainfall return into the medium term with potentially more traditional westerly winds moving in for the end of the month.

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

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