The flood risk remains the biggest concern nationally through QLD and NSW and the news is not good, with further rain and thunderstorms expected from tonight through to around Thursday, when we may get away with a few drier days. However, the storm risk does return during the weekend with the next trough and that may linger through to the end of this period leading to more rainfall.

Trade winds over the far north is expected to bring widespread showers and moderate to heavy falls. The trade winds continue throughout this period, representing the wet season increasing as we head into December. More storms will be seen over Cape York as well throughout this week.

For the east coast and again the southeast and central inland, pay attention the potential for further heavy rainfall develop next week with a coastal trough combining with onshore winds and the residual trough across the inland leading to widespread rainfall and heavy falls.

Lets take a look


Rainfall Next 10 Days

Rainfall, heavy and extensive over the coming 2-3 days will likely to lead to further areas of flooding, with the flooding moderate by week's end in many river systems. Some locations could see falls of 100-200mm of rainfall in the coming 2 days alone and up to 300-400mm over the course of the next 10 days. As mentioned, global models have suggested this in the medium term and now we are seeing that in the short term, so the risk is high for flash flooding and riverine flooding. The rainfall will likely ease by Thursday with a weak ridge moving through but the showers and thunderstorms return during the weekend with further moderate to heavy falls expected. The far west is expected to see showers and thunderstorms but it becomes more widespread the further east you go throughout this period.

Thunderstorm Forecast Tuesday

Thunderstorms are expected to remain scattered this evening and overnight and become a large slab of thundery rain Tuesday for those over the southeast and central areas. A new batch of storms will form west of this rainfall along the trough during the afternoon and evening with all modes of severe weather possible. Thunderstorms will also fire over the tropical north but more isolated in nature.

Flash Flood Risk Tuesday

Flash flooding is a risk throughout tonight and Tuesday over the central and southeast areas, with rainfall of 100-200mm possible within 12hrs over some locations. You do not need the rainfall to fall overhead to avoid the flash flood risk. The catchments are saturated and are expected to respond very quickly to heavy rainfall.

Large Hail Risk Tuesday

Large hail is a moderate risk along and immediately to the east of a trough over inland areas during the afternoon and evening.

Damaging Winds Risk Tuesday

Damaging winds are a moderate risk with thunderstorms along and immediately to the east of a trough over the inland during the afternoon and evening.

Riverine Flood Risk Tuesday

Widespread rainfall and thunderstorm activity will keep the flood risk elevated throughout this period with the chance of flash flooding exacerbating the flood peaks down already swollen river systems. Flooding may develop in catchments that are yet to reach flooding classification. I will review the state wide flood risk tomorrow after what falls overnight.

DATA - More details on this in the video - but this shows you the flow pattern of major ingredients in the coming 10 days or so.

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

00Z GFS - Precipitable Water Values - Next 16 Days

00Z GFS - Rainfall Accumulation - Next 16 Days

More details on this after 9pm tonight in the full model and rainfall wrap.

There is a very sharp drop off in rainfall but note the uneven distribution of rainfall throughout the east - I do think there will be rainfall out west from tonight through tomorrow and this models suggests in the warning area where rainfall is falling, that there is no rain. This is why you need to cross check with what is happening in reality

If all the ingredients come together, the eastern parts of the nation could see excessive rainfall once again.

KMA - Rainfall Next 12 days

Something to watch - with this solution an outlier, but not too far away from what is possible.

More coming up in the rainfall and model wrap after 9pm EDT.

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