SA - SHOWERS AND THUNDERSTORMS CONTINUES FOR MID WEEK - SOME SEVERE IN THE EAST AND NORTH.

The humid, tropical and unsettled weather continues not only this evening for some parts but likely to increase for many for mid week, as a deepening trough moves through the region with scattered to numerous showers and thunderstorms developing along the axis of the deepening trough.


Thunderstorms are likely to turn severe in pockets of the Agricultural areas and extending back up to the northeast pastoral district with heavy falls and damaging winds the main issues at this time.


With the trough progressing eastwards by the end of the week, a brief reprieve from the oppressive humidity is likely for coastal areas but that won't last long with the showers and thunderstorms continuing for the northern areas set to descend southwards once again next week ahead of another system.


So the unsettled run will continue, the rainfall won't be quite like the weekend at this time, with both systems through the outlook. However, keep an eye on the weather over the northern areas into the southern NT, as flooding rainfall may redevelop for these areas with a deep trough and tropical moisture lingering throughout the region.


Some communities may be cut off as will some roads through the outback.

FORECAST

Rainfall Next 10 Days

Rainfall remains uneven in distribution, but many areas may see a return to storms tomorrow and Thursday before the unsettled weather moves into the Outback over the north and northeast. Some areas could see an additional month's worth of rainfall and up over northern areas bordering the NT, could see around 2-3 months worth of rainfall with tropical moisture lingering. Flood risks remain over the far north. The moisture may return to southern and eastern areas of the state next week ahead of another trough emerging out of the Bight. So another period of showers and thunderstorms could emerge throughout the period with more moderate falls before we see a proper clean out of humidity.

Watching the heavy rainfall threat over the northeast as well.

Thunderstorm Forecast Wednesday

Pockets of thunderstorms across the southern and central interior and through the eastern areas of the state with multiple troughs about the region. Storms will likely to develop from late morning through and peak through mid to late afternoon throughout the nation. The risk of severe weather is moderate to high in the red and pink zones.

Flash Flood Risk Wednesday

High moisture levels will lead to an increased risk of heavy rainfall leading to areas of flash flooding once again over saturated regions. In the east, this is where the larger storm clusters will be found with the heavier rainfall totals.

Damaging Winds Risk Wednesday

Damaging winds is a moderate to high risk with thunderstorms where they form. Not everyone will observe damaging winds but the atmosphere is supportive of storms being efficient rainfall producers which may drag down strong winds aloft.

Large Hail Risk Wednesday

I am placing the large hail risk further east where the lingering trough is placed over the border with NSW and VIC. There is a very low chance with the secondary trough further west.

DATA - Refer to video for more on the daily breakdown for the short and the medium term


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

The pattern in the short term largely unchanged in the short term. Severe weather over the south and east will gradually contract further east over the coming days but possibly return next week. The heavy rainfall risks leading to flooding over the inland of the nation remains in the short term. The monsoonal low over the NT may spread into WA and bring up rainfall chances for a drier WA, this would then shift rainfall chances across SA and VIC into the medium term. The east coast, keep an eye on the trough next week, we could see a significant rainfall event develop between the easterly winds and the trough that hangs up in the medium term. Heavy moisture will sit over QLD and this will lead to persistence forecasting, so not much change to what you have right now.

00Z GFS - Precipitable Water Values - Next 16 Days

The very deep moisture is with much of the nation for the coming 10 days before we start to see the pattern shift. Clearly the GFS prints out the impact of what a tropical low does running through WA. That is an idea that is on the board but not well supported. The monsoon trough may snap back and offshore at the end of the run increasing the cyclone risks over the north of the nation.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for more information.

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to video for more information.

00Z GFS - Rainfall Accumulation - Next 16 Days

Refer to video for more information.

A closer look in - more details in the video rainfall over the north and northeast needs to be watched regardless of the jerking around in details from the GFS. Heavy rainfall remains a risk with thunderstorms.

More details coming up tonight with a look at the full model suite and the rainfall projections for the short, medium and long term.




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