SA - SHOWERS DEVELOPING TOMORROW NIGHT WITH A COLD BLAST SURGING NORTH THROUGH THE STATE.

The weather is set to turn from the mild to warm and sunny weather of late across the state and be replaced with a very could and gusty southerly flow that will move in behind a front from later tomorrow into Wednesday.


Showers are forecast to develop along the front tomorrow night over the SE Districts and then extend along the Southern Ag areas during the overnight. Some locations could also see some local thunder with the front itself, more likely SE of Adelaide. The rainfall totals though are forecast to remain light under the drier airmass.


Now the position of the low is key to how much rainfall emerges through the stream showers that set up off the Spencer and St Vincent Gulf and how they impact communities downstream in the of the wind bearing, so that will be a feature to watch. There could be some falls over 20mm with these bands.


Showers will be more extensive over the southeast areas bordering Victoria with moderate falls also over 20mm for the period possible. Light falls of up to 5mm for the EP is reasonable.


The weather remaining dry over inland areas.


As we move closer to the weekend, the air will remain dry with a clearing sky, the cold air allowing temperatures to fall away fairly easily. Some areas in the east and about the Flinders could see the first frosts of the season so that means growers need to beware.


The daytime temperatures will start to move towards the average by the weekend and we could see warmer days next week as the flow turns northwesterly ahead of the next front moving out of WA.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall is forecast to begin over southern areas of the state from tomorrow night with mainly light falls expected, though we could see a few moderate falls about the lower southeast. The showery weather continues during Wednesday, Thursday and Friday before easing into the weekend. As mentioned, the rainfall is highly dependent upon the position of the low pressure system near VIC/TAS and the subsequent wrap around troughs and how they roll over the south of the state. Certainly a good chance of stream showers producing moderate rainfall over the Ag Areas east of the EP and these could be found about the Flinders and Mid North. The rainfall will begin to ease from Friday and into the weekend. A drier weekend for most and then into next week. Some model issues around the spread of moisture coming out of QLD into SA and whether this will introduce showers into the east. There is also the chance of rainfall developing from frontal weather later next week as well emerging through the westerly wind belt coming through WA.

Farmers and Graziers Alert - Mid Week

Cold and showery weather is expected to develop from later tomorrow night and continue through Wednesday and peaking during Thursday before easing Friday. A pool of very cold air could sweep through during Thursday.

MEDIUM TERM - May 9th-16th 2022

Rainfall Anomalies

Looking at a substantial rainfall event emerging through the northeast and east of NSW into eastern QLD as moisture via the positive SAM combines with an upper trough that will be departing the east through this time. Some of the elevated rainfall chances could extend into central and eastern NSW as well. The rainfall developing from the west could begin to spread across southern parts of the nation but the signals not overly strong for above average rainfall but will placemark the movement of that event over southern and western parts of the nation.

Temperature Anomalies

Not much change to the temperature guide as we travel into mid month, with the cooler bias continuing in the west for now with frontal weather and rainy skies. The rain event over the east of QLD could pump moisture south and west into the eastern inland leading to more seasonal weather, though cooler weather possible under persistent rainfall over SE QLD and NE NSW. Warmer than normal weather over the northern tropics with the moisture content perhaps subsiding a bit but the lingering warmer waters around the tropics leading to elevated temperatures. Perhaps warmer nights and days for the ACT and surrounding districts in NSW ahead of the rainfall developing from the west.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.


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

More details on the daily breakdown over the short and medium term so refer to the video. But not much change is expected from this morning's synopsis, however there are some interesting highlights in the medium term that need watching.

00Z GFS - Precipitable Water Values - Next 2 Weeks

Moisture content across the nation is forecast to increase once we lose the colder drier airmass that is over the southeast and south for much of this period, but note that the dry colder surge struggles to get into the northeast and really, is overridden in the medium term. Also moisture profile improves in about a week in WA. And will we see another large surge of moisture via the jet stream into the medium term through WA and then across the country?

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 position of the low through Bass Strait and the subsequent passages of the troughs will determine the rainfall for SA in the short term, then we look to the north and west for the next broad opportunity for rainfall in the medium term as discussed.

More coming up tomorrow including the Climate Outlook, as you can see some larger systems are ahead of us again, but do they continue into the back half of May or into June as well? That coming up from later tomorrow morning and your next update after 8am EST.


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