It is a slow process but once the humidity is here, it will be accompanied by warmer weather and a higher chance of rainfall for much of the eastern two thirds of the nation.

Until then, we have another few days of high pressure and dry air leading to more settled conditions for SA, VIC and much of NSW.

A trough is likely to deepen Monday through QLD with rounds of showers and thunderstorms working through from west to east through QLD and this will clip the northeast of NSW. Storms likely severe.

The west will see cooler conditions developing today with a front passing through. Showers could be moderate at times along the west and southwest coasts with the front and with the colder air behind the system. A run of below average temperatures likely to continue.

This system is the one that will push out the ridging and high pressure over the southeast states with moisture being drawn south and southeast through the nation from the tropics, with rainfall chances coming up mid to late week for SA, VIC and NSW once again.

The system responsible for this inclement weather is being poorly modelled at this time.

Lets take a look


Rainfall Next 10 Days

Rainfall is remaining low confidence for those of you living through the southeast and southern inland of the nation with a large amount of divergence in modelling of this lead system which is causing havoc with your rainfall totals from run to run. The higher confidence in rainfall is found over the SWLD of WA where showery weather is in the process of moving through today and sticking around until mid week. The tropics will remain active with scattered showers and thunderstorms with uneven distribution of rainfall. And scattered showers and thunderstorms through parts of NE NSW and SE QLD today will stick around over Central QLD with locally heavy falls with thunderstorms. Again uneven distribution of rainfall is likely. There is sometimes little skill in forecasting specific amounts during these periods so just be aware that warm season rainfall can be incredibly frustrating to predict.

Thunderstorm Forecast Monday

Thunderstorms are expected to turn widespread through the afternoon and evening with the risk of these storms turning severe. Large hail and damaging winds are expected to be the main concern but heavy rainfall leading to flash flooding is also possible with the larger thunderstorm clusters.

DATA - Refer to the video for more.

Euro 12z - Surface Pressure Pattern and Rainfall Distribution - Next 10 days

This pressure pattern is in reasonable agreement with GFS and shows multiple system evolving out of the northwest through WA and then amplifying when the warm cored systems clash with the colder air floating about the southern parts of the nation. This is making the weather volatile, we have seen that in the form of severe thunderstorms in recent weeks. The storm risks are seeping further south and be prepared for storms to pack a punch over VIC, parts of SA and southern NSW which have been sitting in the cooler more stable air for this spring so far. The north, unsettled and wet, the BoM forecasts are way too dry for the potential sitting up there so be prepared for more active weather than what is advertised. That will help spawn the wet November for much of the nation.

Euro 12z - Precipitable Water Anomalies - Next 10 days

Moisture as per last night and this morning's video is unchanged, the GFS is showing a very soupy airmass eventually being able to move south into the central and southeast areas of the nation as the upper high breaks down. This will start the procession of rain events and thunderstorms outbreaks in a warmer and humid atmosphere for most areas, but the SWLD could sit under drier air more often than not with riding persisting.

Euro 12z - Rainfall Accumulation - Next 10 days

The latest run has the low passing over land and trough a little slower later this week into the weekend, where the GFS has it offshore.

GFS 12z - Rainfall Accumulation - Next 16 days

GFS has 3 systems on the board that evolve out of that moisture plume through northwest WA and the NT that magnifies along a trough over southern and southeast Australia. Classic IOD weather. The east unsettled for most of this period BUT a positive SAM phase will see totals over the east increase.

CMC 12z - Rainfall Accumulation - Next 10 days

The path of the low pressure system that forms over SA is further north so hence why heavier rainfall later this week for VIC and NSW.

CFS 12z - Rainfall Accumulation - Next 6 Weeks - Ensemble

Very wet and humid over northern and eastern Australia and you can see that impact on the Central parts of the nation too.

CFS 12z - Rainfall Accumulation - Next 6 Weeks - Control Member

The heavy rainfall signal is increasing day to day on this particular model. Will it end up like this, probably not, but this is a signal to get prepared for a very wet period over southern and eastern Australia. I will point out that the fact this model has a drier look for the tropics, which I don't agree with, if it had the heavier moisture there, maybe it is under doing rainfall totals, which is something we have to consider.

I will have a medium term outlook this morning, farm focus and a look at the impacts of humidity and temperatures nation wide over the coming 2-4 weeks and much more.

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