The pattern is turning gradually more humid and unsettled as a series of weak troughs meander through southern and eastern parts of QLD over the weekend, before extending into Central QLD and the southeast bringing the chance of showers and thunderstorms to most of us from next week.
Thunderstorms over the coming days will be mainly isolated, however in a hot airmass, these storms could be strong and gusty, with damaging winds gusts. Over the weekend that risk may increase further as we track a sharper trough over NSW during Sunday.
Next week the tropical weather is expected to increase further with a wave passing through from the east over Cape York and then on by into the northern Top End. As this wave becomes more organised, we may see a low form west of the state, and if this does occur, then a monsoonal flow may be drawn into the region enhancing rainfall and thunderstorm activity with gusty humid but thankfully cooler northwest winds.
Along the east coast, showers increasing thanks to onshore winds developing. This will take place once a high pressure system emerges in the Tasman Sea. That pattern supporting a return to wet and stormy weather to round out the year.
Lets take a look
Rainfall Next 10 Days
Rainfall is patchy and related to thunderstorms over the coming days, so if you are living over the inland, you know the deal, some areas getting a nice dump but many not seeing a drop. The coverage of rainfall is anticipated to increase next week as a trough from NSW moves into the south from Monday, a band of cloud with patchy rain and thunderstorms will develop and slowly move north through the first half of next week, though coastal areas should remain dry for now. The northern tropics by early next week should return to the daily afternoon and evening showers and thunderstorms, these are likely to increase as we get closer to Christmas, thanks to a tropical wave passing through from the east. Then the trough over the southern and central interior will begin to stand up and strengthen over Christmas with an uptick in showers and thunderstorms forecast from mid week and likely right through Christmas. Far western areas may see less rainfall. Coastal showers may also increase from later next week with onshore winds developing.
Tropical Depression Formation Risk - December 23-30 2021
Watching the northern waters very closely through Christmas with a developing tropical wave passing through from the east. It may assist in enhancing rainfall but also dragging in the northwest monsoon. Something to watch.
Thunderstorm Forecast Friday
Thunderstorms are forecast to develop once again near a stationary trough over southern interior parts extending through to Central areas. Storms may be gusty at times and efficient lightning producers. Heavy rainfall is a low chance at this time.
Damaging Winds Risk Friday
A low end risk of damaging winds with elevated thunderstorms over the interior during the afternoon and evening.
Flash Flood Risk Friday
A low end risk of flash flooding with elevated slow moving storms over the Downs during the afternoon and evening.
DATA - Refer to the video for more details!
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days
The pattern from now into Christmas remains largely unchanged from this morning's analysis so expect the confidence to remain fairly low in the placement of moisture and troughs through the coming days, that is due to the models trying to figure out what the monsoonal weather will do north and east of Australia. More information on that in the video.
00Z GFS - Precipitable Water Values - Next 16 Days
The forecast confidence is quite low on all elements and this will play havoc with the moisture spread throughout the nation in the short and medium term. The one system that does offer a higher chance of spreading moisture southeast and east across the nation is the trough passing through this weekend, no rain expected from the system as it passes through drier air over SA and WA but once it moves into eastern VIC and into NSW, it will find the moisture and see rainfall increase. Beyond then the moisture builds over the northern tropics and things start to look very unstable over the northern tropics moving forward into the end of year. Where the tropical weather goes, so too will the humid weather and rainfall chances.
00Z GFS - Rainfall Accumulation - Next 16 Days
More details in the video.
A closer look in - note the numbers move around over and over again in relation to the tropical low off the northwest and the monsoon trough forming offshore north and northeast. More details coming up at 9pm EDT
A broader look shows the moisture creep in the medium term, but it will chop and change and thunderstorms over the southeast and south will deliver the obvious heavy rainfall chances.
More to come after 9pm EDT on all things rainfall, there is little confidence in the medium term with the tropical weather playing havoc across the agencies so remember, LOW CONFIDENCE nationally!