The tropics are staying put across southern and eastern Australia, but for much of NSW, the pattern is suppressing rainfall with a ridge over the region capping cloud development and shower coverage inland of the coast.

Along the east coast, it has been wet north of Taree with onshore winds bringing in quite a few wet days, some areas getting above 100mm of rainfall for the week, some cracking 200mm. The wet season for the east is just around the corner as well with the seasonal shift in Autumn bringing more unstable weather around the top of high pressure systems as the migrate northwards.

During the coming few weeks we will have the peak of La Nina, but there is lag in feeling that impact which is about 4-6 weeks, so placing that impact of La Nina in late February into early March. Just something to think about for those living in central and eastern areas which were hit hard last year but the Autumn floods on the back of the last La Nina peak.

Lets take a look at the short term and a peek into the medium term.


Rainfall Next 10 Days

Rainfall is expected to remain largely over the western side of the state for the coming few days, closer to the impacts of the trough lingering over SA. The trough will meandering east slowly, opening up and weakening through the coming few days meaning the showers and thunderstorms will become more widely spaced over in the west. The trough will enter the state around Australia Day with that impact expected to be felt with scattered showers and thunderstorms over the southern and central parts of the state in particular west of the divide. Storms may be heavy and severe, so will keep an eye on trends. The coverage of rainfall then spreads east and north through the remainder of the week into the weekend with some moderate to heavy falls with thunderstorms possible. The area to watch is northwest of the state through the Outback on the NT and SA where deep tropical moisture is bringing torrential and near record rainfall. That may spill over into northwest areas over the course of the weekend into the last week of January.

Thunderstorm Forecast Monday

Thunderstorms are possible during the afternoon and evening over the far west and northwest where severe thunderstorms are possible. Heavy rainfall leading to flash flooding is the main concern. With a ridge over the eastern areas, the day will be stable with high humidity developing.

Flash Flood Risk Monday

Flash flooding is a very high risk over the far northwest of the state but more likely over northeast SA where the trough and very deep moisture will combine to continue the outback flood threat.

Severe Weather Potential - Wednesday through Friday

The trough will advance eastwards this week causing the heavy rainfall and severe thunderstorm potential to follow into the state. The risk is low to moderate, but some areas could see flash flooding from thunderstorm activity from Australia Day to around Friday at this time.

DATA - More analysis in the video.

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

Not much to add from the video other than disregard that system over the southeast in the medium term, the model will likely remove that in the next run. What it is suggesting is that the weather is expected to remain unsettled for northern and eastern areas of the nation with a strengthening monsoon. The weather in the west remains hot and dry, that carries a high confidence. As we enter February, we should begin to feel the impacts of that peaking La Nina which it is in the process of doing.

00Z GFS - Precipitable Water Values - Next 16 Days

A very rich environment for productive rainfall, of record proportions for some areas. We have seen that occur in many parts of SA and do not think that cannot be replicated again off the back of what we are seeing on the synoptic scale in combination with the near record moisture values.

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 - looking at the synoptic scale, the rainfall totals will bounce around a lot and with thunderstorms in the mix in the very high moisture levels, rainfall totals will exceed what is shown here in many areas.

More weather coming up tonight on all things rainfall and the models for the week ahead. Take care in the wild weather across parts this evening.

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