SA - HOT AHEAD OF A MILDER SOUTHERLY CHANGE. A THUNDERSTORM POSSIBLE IN THE EAST.

Otherwise we are looking relatively dry for a number of days through to the weekend with high pressure close by, spoiling any rainfall chances, however, the new centre of high pressure out to our west may result in cooler air for a few days for the south.


But that high will pass through to the southeast and east quickly. This will see temperatures move towards seasonal values again for the south but above average temperatures for the west and north as the flow tends more northeast to easterly.


A middle level trough may emerge from WA over the weekend, it is moisture staved at this stage, but if moisture can be left behind from the first feature, we may see high based showers and thunderstorms over the northern half of the state on Sunday and into early next week while remaining very warm to hot.


The unsettled weather may increase further from this time next week, some modelling supports a low pressure system forming to our south and dragging in more moisture into an associated trough. That would be the next serious chance of more widespread rainfall.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall is limited but over the next 24 hours, there could be about a dozen thunderstorm cells over eastern areas closely Adelaide to Hawker eastwards with a trough lingering in the east, finding the moisture that will be drawn southwest overnight into this upper feature. The thunderstorms could be heavy if you get under one, but most will remain dry. The weekend mostly dry for Ag Areas with high pressure to the south but over central and northern areas, a middle level trough sailing through may trigger light high based gusty thunderstorms Sunday and Monday. A stronger system is being picked by models from this time next week but I will wait a few more days before acknowledging this seriously.

Thunderstorm Forecast Wednesday

Thunderstorms are a chance from Hawker to Victor Harbour eastwards, but more likely east of the the hills closer to the VIC and NSW border where the trough finds the deeper moisture profile.

Flash Flood Risk Wednesday

A low chance of flash flooding IF thunderstorms get underway and push into the eastern areas during the afternoon and evening.

Damaging Winds Risk Wednesday

A very low chance of damaging winds clipping the far east on Wednesday afternoon.

DATA - Refer to the video at the top of the page for more details.


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

The pattern is starting to factor in the monsoonal pattern descending from the north and as I keep mentioning, all guidance beyond about 7 days will start to go a little haywire and tricky to track. Once we get a better handle on how the northern tropics are behaving then I think the modelling will settle down. But in the short term, very wet for QLD and NSW with multiple troughs and we have already seen that play out with additional flooding underway and heavy rainfall ongoing for another 24hrs. Severe storms have broken out over parts of western QLD and NSW, these will descend into VIC over the course of the next 24 hours, a sign of what is to come weather wise this summer. For the west and through to SA, it is quiet near a ridge, with warm to hot weather, the heat on over WA through this weekend and into next week with a northeast flow dragging in the heat engine. The moisture will be folded into this airmass next week and the return of inland showers and storms looks a good bet. The system to watch next week will be the low pressure system as mentioned in the video for southeast and eastern Australia.

00Z GFS - Precipitable Water Values - Next 16 Days

The deep moisture profile over the east is largely remaining in place for the coming 2 weeks, it is now a question of how much low pressure gets drawn into this airmass during this period. Clearly there is some issues around the timing and scale of troughs through the outlook period, but the fact we have troughs in the region with this powder keg airmass, is of great concern for the flood zones. Elsewhere the weather is looking relatively seasonal for WA with moisture content where it should be and for southern states such as VIC and SA the air is relatively seasonal as well under this guide. But note the tropical moisture deepening in response to the monsoonal flow heading further south away from the equator and more tropical waves surging west through northern waters enhancing rainfall. Again this is not a great sign for those needing a few dry weeks as this moisture will be sheared southeast and south into the nation during the back half of the month, on top of what we are dealing with right now over eastern areas which are flooded and still being rained on.

00Z GFS - Rainfall Accumulation - Next 16 Days

More information can be found in the video and in the update on all things rainfall coming up from around 930pm EDT tonight.

A closer look in - I am expecting numbers to come up through the days ahead with the moisture and synoptic scale in place so watch this space carefully.

More details to come after 9pm EDT.

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