The humid and unsettled weather pattern continues for many areas through the coming week, but more likely to increase in coverage as we move towards the weekend as a trough from the NT moves east into the west and another trough over SA moves into NSW and then QLD bringing widespread showers and thunderstorms.

A very deep moisture supply will mean that thunderstorms that form may be very efficient rain producers with heavy falls about.

The most severe weather is expected for far western areas of the state initially where flash flooding is a high risk through the period. That risk may translate into the central and southern inland areas later this week and then through to the southeast perhaps by the weekend.

A trough over NSW is expected to stall out over the southern and central parts of the state during the weekend which may bring showers and thunderstorms to the same regions day after day. This could increase the flood risk if the monsoon trough fails to move northwards and detach from this trough so will be watching closely.

Overall it is a very humid and unsettled period for the state which is expected under a La Nina Summer.

Lets take a look


Rainfall Next 10 Days

Rainfall is expected to be uneven in distribution throughout the state during this week, however the better coverage of rainfall will be found over the western and southwest districts with heavy falls developing with thunderstorms. Flash and Riverine Flooding may be a significant risk. The rainfall coverage along the coast remains light in onshore winds with showers from time to time. During the weekend, the weather may turn more unsettled as the trough finally arrives and widespread showers and thunderstorms developing with locally heavy falls about for southern and central areas west of the divide. The monsoon trough over the north will drive heavy rainfall and gusty storms with some locations possibly seeing up to 400mm through the coming 10 days. Finally, watching a tropical low that may form near Gulf Waters.

Thunderstorm Forecast Tuesday

Thunderstorm forecast largely unchanged from yesterday with the stagnant pressure pattern. Storms may turn heavy at times in the far west and southwest with some pockets of flash flooding. Thunderstorms should remain below severe thresholds over the remainder of the state but stable air along the coast.

Flash Flood Risk Tuesday

Flash flooding remains the major concern weather wise across the west and northwest with some locations recording 50-100mm during the coming 24hrs with slow moving thunderstorms.

Riverine Flood Risk This Week

Extensive rain and thunderstorm activity for the coming 7-10 days will lead to inland flood risks remaining very high with disruptive and damaging flooding possible over western areas, especially if the trough moves in from the NT and the monsoon trough lingers over northwest and western areas. Some communities may be cut off as well.

Severe weather potential - Monday through Friday

The risk will continue daily for western and southwest areas with flash flooding the major concern. Areas of heavy rainfall developing with the monsoon trough moving southwards and merging with the southern trough will see riverine flooding become a concern for outback communities with areas cut off for days/weeks possible. The thunderstorm risk will advise eastwards gradually through the weekend and the thunderstorm risk will be reviewed and new charts issued mid week for that if that looks to be a moderate to major event.

Flooding over the majority of NT is of concern this week with clusters of severe thunderstorms, heavy rainfall and gusty winds with the monsoon trough up north and the trough over central and southern areas merging to produce above average rainfall.

DATA - Refer to video for more details relating to the daily breakdown and what you can expect.

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

The pattern remains largely unchanged. As mentioned in the video, the elements to watch in the short term, the monsoon trough over the northern parts of the nation and how does that then interact with the inland trough over SA and the NT this week? That may produce significant flooding issues. The other element is the severe weather risk covered off for SA, VIC, NSW, ACT and QLD over the coming days with the trough slowly working it's way through very moist air. The west you stay fairly similar to what you have now, temperatures are expected to surge back into the 40s over the SWLD. In the medium term, watch the monsoon trough for further rainfall chances nationwide. Does the high pressure system ridge in further south allowing for more easterly winds to dominate the nation or do we get dry air developing with the ridge sitting higher over southern parts of the nation? These questions will be answered throughout this week with some luck.

00Z GFS - Precipitable Water Values - Next 16 Days

A very deep moisture profile over the nation with heavy rainfall and thunderstorms about many areas. I will mention watch the medium term, we could see an abating of the high humidity and rainfall chances over the nation with the monsoon trough being kicked back northwards towards the tropical north. Could increase the cyclone risk over northern parts of the nation into early February.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for further information

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to video for further information

00Z GFS - Rainfall Accumulation - Next 16 Days

Refer to video for further information

A closer look in - the rainfall guide remains low confidence at this time for southern areas but for northern parts, the monsoon driving the heavy rainfall opportunities and tropical lows that form in the trough will dictate the intense rainfall potential into the medium term.

More coming up with the wrap on all things rainfall and the modelling tonight to see whether we can get some clarity on the severe weather in the short term and the monsoon trough driving the heavy rainfall event for the north and central areas.

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