The heat is building as we edge into New Years, with a high pressure system on the way out to the east sending most of the nation into a northerly or northwest flow, the seasonal weather and or cooler weather will be found over coastal areas of SA and back through southern WA.
Heavy rainfall over northern Australia will tend more scattered over the next day or so, with widespread showers and thunderstorms to return from later Sunday for the NT and northern WA with a new heat low building.
A stalled boundary over the southeast and east over the weekend and into next week may develop into a more substantial storm outbreak with severe thunderstorms possible in about a week from northern VIC into NSW and southern QLD, possibly eastern SA with a humid and warm airmass.
The west, set to bake again from next week with an easterly flow returning.
Lets run through it
Rainfall Next 10 Days
No change to the rainfall from this morning, the guidance is not especially great in the medium term as outlined, the monsoonal trough over the north sets the rainfall projections into a tail spin as they struggle to place tropical lows and or cyclones. There is no skill in forecasting where the monsoon trough and or tropical weather sets up over the nation. In the mean time the south of the nation looks quiet, little rainfall is anticipated at this time. Inland areas of NSW and QLD back through to the tropics may see showers and thunderstorms increasing. Troughs digging down into VIC and eastern SA could see storms reach these regions later in the period. The west stays mostly dry with high based storms over the eastern and central interior with a heat trough setting up in the easterly flow. The monsoon should move south over northern Australia again from about the 10th of January and rainfall accordingly, will increase from the north. For now I will leave the forecast unchanged but will update in the morning.
Thunderstorm Forecast Thursday
Thunderstorms thin out across the nation on Thursday with heights coming up and troughs reorganising. There are middle level troughs over the interior which will give way to elevated storms, but only a small chance that storms turn severe over the nation tomorrow. Rain and thunder over the northern tropics will ease later Thursday. Storms may be gusty over the NT and northern WA but the coverage is not especially high.
Thunderstorm Forecast Friday
Thunderstorms are anticipated to increase in coverage on Friday as a heat low deepens over parts of the NT and WA, with storms tending gusty during the afternoon and evening. The coverage a little more widespread over the northern tropics during the afternoon and evening with heavy falls in a couple of places. Elevated storms over the outback will continue, but most of the rainfall light if anything.
Thunderstorm Forecast Saturday
Thunderstorms are expected to continue over northern tropics during the afternoon and evening with some of the thunderstorms expected to be gusty at times as well with higher instability levels. Thunderstorms are also expected to extend down a trough and in advance of a wind change through SA and into VIC and western NSW, but storms are anticipated to be mostly elevated and dry.
Severe Thunderstorm Potential Next Monday and Tuesday
An area to watch through the outback extending over the northern tropics, a fairly decent thunderstorm outbreak could result in damaging winds becoming a widespread event Monday and Tuesday
Severe Thunderstorm Potential Next Thursday
A low end threat at the end of next week for the southeast inland. A sharpening area of low pressure connecting with moisture will lead to scattered showers and thunderstorms, some may turn severe.
Tropical Waves - Next Week - December 29th 2021- January 5th 2022
Tropical low (08U) is moving through FNQ and is expected to pop off the FNQ coast with heavy rainfall clearing into the Coral Sea. The monsoon trough is expected to drift north of the mainland back over open water and next week a few waves of storms may begin to gather strength and organise into low pressure over the northwest and north of the nation.
Excessive Heat - Next Week - December 29th 2021 - January 5th 2022
Excessive heat is expected to be transported through to the eastern and central inland north and west of the divide with a large high moving east. The highest heat anticipated over outback areas. Coastal areas will feel 1-2 days of excessive heat but nothing out of this world over southern areas. The excessive heat (40C and above) will return to the west coast next week in WA.
DATA - Watch the video for more information.
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days
More details in the video from day to day analysis.
00Z GFS - Precipitable Water Values - Next 16 Days
Very humid air over northern Australia is extending through QLD today and will continue with high heat with the monsoonal break in place. The moisture will at times, be drawn into troughs through the central and eastern interior with thunderstorms denoting this occurring. The monsoon is expected to deepen next week and you can see from run to run, the GFS placing tropical lows in different locations. The signal is unchanged at this time.
00Z CMC - Rainfall Accumulation - Next 10 Days
More information can be found in the video this evening, I am noting the rainfall for the southeast and have not drawn it in on my charts yet as the confidence is not high, but watch tomorrow's update for more details.
00Z GFS - Rainfall Accumulation - Next 10 Days
More information in the video.
00Z GFS - Rainfall Accumulation - Next 16 Days
More information is found in the video.
Very low confidence in the forecasting beyond about 5 days at the moment so be aware of that as you look at all the apps etc. The features to watch, the monsoon trough up north, the deepening trough over the eastern inland which could also spark a storm outbreak mid next week and the heat building over the interior in advance of any monsoonal incursion.
More tomorrow from 8am EDT.