** Just a heads up that I will be travelling on Monday and no update is expected on Monday until Monday evening - updates to continue through the weekend ahead of my trip **

The weather is now moving into a more dynamic phase with a fast flow pattern moving through the southern parts of the nation, seeing a large variation in temperatures from day to day and changeable weather over the southeast. For SA and back to southern WA, it is likely to stay stable, settled with relatively seasonal weather for the period from now through to Christmas.

I am not ignoring SA and southern WA, your forecast is rinse and repeat at this time over the coming 7-10 days.

For the north, the storm activity is ramping up and we have already observed some significant convection in the past 24hrs and another batch of strong storms is now on the prowl through northern districts this evening, this activity a sign of what is to come with elevated rainfall associated with the tropical waves passing through. The monsoonal flow may be here by this time next week for parts of northern Australia.

Finally in the east, onshore winds will feed a lingering trough with thundery weather increasing from mid next week, post the showers and storms this weekend, the humidity is set to deepen, so the searing dry heat will be a thing of the past next week with showers increasing for the coast, and storms increasing for the inland.

Lets take a look - it is 11 minutes tonight to break down the short and medium term and looking at the tropical impacts for the end of the year which could be significant for many areas.


Rainfall Next 10 Days - December 17th-27th 2021

Rainfall as mentioned this morning is increasing through the outlook period. We have a short sharp burst of rain and thunderstorms through the weekend over the southeast, mainly Victoria and NSW. Could be some moderate falls with this mass of unstable weather. Then the wet weather shifts north as ridging moves in so for next week, if you are living over SA and WA, dry weather right through to Christmas, clearing for VIC, but the showers and thunderstorms may linger for parts of NSW and more widespread through QLD and the bulk of the NT through to northern WA. Moisture increasing, troughs deepening and a monsoonal flow approaching northern Australia through the outlook will result in heavy rainfall developing in scattered pockets.

Rainfall Next 16 Days - December 17th- January 3rd 2022

Rainfall is expected to become heavier over the northern and northeast of the nation where the monsoon trough and a tropical low or two will drive areas of heavy flooding monsoonal rainfall. The moisture from this will sweep south and east, but it is yet to be determined where that path will be. For eastern Australia, independently of the monsoonal weather the onshore flow will tend more unstable and moisture being drawn in will result in widespread showers developing throughout this time through to early January. The west may remain fairly dry over southern WA through SA and into VIC, but it is dependent upon the tropical moisture moving south and east from the north of the nation.

Thunderstorm Forecast Saturday

Thunderstorms are forecast to be more widespread on Saturday afternoon and evening through VIC, NSW extending back into central Australia and over the NT and WA. The storm focus most robust over the Top End and over the southeast of NSW including the ACT and eastern VIC. Scattered storms could be gusty and heavy with small hail in the southeast. Storms could be gusty all the way through central Australia with little rainfall but tend heavier and gusty over the Top End where sufficient moisture returns and tends deeper along the north coast.

Thunderstorm Forecast Sunday

A cold front captures the slow moving trough and invigorates it over VIC and NSW during Sunday with storms tending severe with high winds and locally heavy rainfall. Small hail also possible in the stronger storms. Gusty winds and little rainfall expected over the outback, however as you move further north to the northern Top End and Kimberly, storms tend heavy with the chance of locally heavy rainfall.

Thunderstorm Forecast Monday

Thunderstorms contract into northern parts of the nation and become isolated in the east as the trough weakens and the dynamics supporting severe weather moves southeast and away. Heavy thunderstorms are possible over the northern third of the NT through to the Kimberly with a trough deepening over the region. Some of these storms could be gusty.

Tropical Depression Formation Risk - December 23-30 2021

Watching the region north and northwest of Australia where a tropical wave may begin to move into favourable conditions for further development into a low pressure system, enchanting rainfall but also allowing for a northwest flow to be drawn into the north of Australia enhancing rainfall as well.

DATA - More details found in the video tonight - to cut down the reading time.

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

Day by day break down in the video.

00Z GFS - Precipitable Water Values - Next 16 Days

More information in the video but note the deeper moisture spreading through the north and east of the nation as the monsoon returns and the easterly winds deepen. The west is looking drier and settled.

00Z GFS - Rainfall Accumulation - Next 16 Days

More details including the fly around in the video

00Z GFS - Rainfall Accumulation - Next 10 Days

More information in the video

00Z CMC - Rainfall Accumulation - Next 10 Days

More information in the video

More coming up on Saturday morning - have a great Friday night.

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