The severe thunderstorms have erupted this afternoon as forecast along the upper trough moving into the very moist and unstable airmass already in place over the southeast and east of the nation. Storms have already dumped falls over 40-50mm in some parts of VIC and heavy rainfall is continuing to fall. Overnight there were falls over 90mm in parts of southern VIC.

Along the surface feature through NSW and eastern VIC, scattered elevated showers and thunderstorms have been in progress for some time today and that activity is slowly moving east and expanding as it does so, drawing upon the humid and unstable east to northeast flow in place between the high over the Tasman and the ghost of Seth which is currently sitting offshore the Sunshine Coast.

The weather is set to become volatile in these areas over the next 2-3 days so apologies to our friends through SA and WA, your weather is benign, stable and little rainfall is expected at this time, your time will come, I am not actively ignoring the weather in SA and WA, there just is not much to work with other very hot weather in the far west grading to mild to warm over southern SA in southeast to easterly winds.

The weather is expected to turn more active over the tropics, but mainly over the QLD tropics for now, there may be a few drier days ahead of the NT with supressed activity leading to filthy heat levels and sunny hot days. That will change next week as the pattern begins to allow for the monsoon trough to emerge north of Australia and see tropical depression risks increase.

Lets take a look


Rainfall Next 10 Days

Rainfall remains largely unchanged but I am bringing up totals for inland NSW and QLD with the higher probability that the trough over the eastern inland, once it lifts out of VIC and southern NSW/ACT, will become stationary and produce widespread showers and storms most days through the entire outlook period. Your number will vary in these zones. The heaviest and most concentrated rainfall has begun to unfold for VIC first and parts of southern NSW, the focus is shifting further eastwards as we move into Thursday and Friday with some big falls on the way and areas of flash and riverine flooding. The west and remainder of the south of the nation dry for now, but watching the evolution of the weather over the tropics which may give rise to more widespread showers and thunderstorms as we go through next week, this descending further south and southwest if the pattern allows and the high falls further south of the nation. Another rain and storm event for QLD and NSW/ACT is also possible next week with the persistent onshore easterly winds taking full control under the positive SAM phase.

Thunderstorm Forecast Thursday

The trough over the east amplifies in response to the approach of an upper feature from SA and the absorption of Seth in the east so widespread showers and thunderstorms with heavy rainfall leading to flash flooding the main concern. Thunderstorms extend through inland QLD, though more scattered, may be gusty and heavy also. For the northern tropics, the thunderstorms will likely trend more gusty once again during the afternoon and evening with dry high based storms extending southwest from the tropics into the Pilbara.

Thunderstorm Forecast Friday

Thunderstorms continue for the same areas into Friday with severe weather continuing over the east and southeast with the trough stationary. Heavy rainfall leading to flash flooding and damaging winds are the main issues. The highest risk once again over inland areas of NSW and VIC. The storm coverage over the north remaining unchanged with a deep trough developing over the northern states. The trough will snake back into WA with a chance of gusty storms but mainly light rainfall totals for now through to the Pilbara and Gascoyne.

Thunderstorm Forecast Saturday

Thunderstorms will slowly contract out of the southeast and move into Central NSW and points north and east near to the east of a trough that will once again pull up stumps somewhere over northern NSW Sunday. The storm focus continues with routine expectations over northern Australia for a monsoonal break period.

Tropical Depression Forecast - Next Fortnight.

Just because it is shaded in over northern Australia, do not think that the impacts of any tropical weather will remain up north. We are already feeling the impacts of the short lived monsoon from Christmas now entrenched over the southeast and east of the nation for the next few days. So this area is critical to seeing how much more rainfall is to come through the next 2-4 weeks and then February which is still looking like the wettest month for Summer.

DATA - Refer to the video for more guidance on the data sets below

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

More details can be found in the video at the top of the page.

00Z GFS - Precipitable Water Values - Next 16 Days

The moisture content is becoming elevated in all regions by the end of the period, setting up the nation for severe weather and flooding events. If tropical weather can also increase through this period, then dangerous weather may be expanded to more regions, again relating to flood risks.

00Z GFS - Rainfall Accumulation - Next 10 Days

More information can be found with the video at the top of the page.

00Z CMC - Rainfall Accumulation - Next 10 Days

More information can be found in the video.

00Z GFS - Rainfall Accumulation - Next 16 Days

The weather set to get wetter as we go along through the month as advertised. The desert areas of the south should remain rain free for now.

More weather coming up tomorrow from 8am EDT. Remember I am in the NT so the posting of information is delayed through the morning hours with the time difference.