So the latest data sets are coming through and there is not a whole lot of change to the synoptic and the consequences that will have on the nation moving through the coming week. That means an easy forecast to remember.
So the rinse and repeat weather will persist for a number of days. Most areas feeling pretty alright for the coming long weekend, before the weather begins to shift into a more humid and unsettled pattern.
Therefore it is a waste of energy changing the forecasts for now regarding rainfall and presenting a video, the signals are still largely unchanged but the confidence is low. Fresh storm charts are posted below.
Rainfall Next 10 Days
The guidance bottom line is very poor and will remain that way for the coming days as the models get better data on what the monsoon is doing up north, whether we see tropical lows form closer to Australia and where the high pressure ridge develops through next week. The further south it sits, more humidity and rainfall will develop over the nation, the further north it sits, less rainfall nationwide and more stable air expected with hotter weather developing. I will leave the rainfall forecast largely unchanged at this time.
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.
Thunderstorm Forecast Sunday
Middle level thunderstorms will continue to move east along and north of a wind change passing through NSW and the ACT. These are expected to be non severe but could be gusty. Thunderstorms also elevated and non severe over the inland of WA during the afternoon and evening. Up north, a developing heat trough will deepen and this will see an increase in showers and thunderstorms once again with some heavy and gusty.
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 as this pulse of energy moves northwest over the course of early next week. Something to watch.
Severe Thunderstorm Potential Next Thursday and Friday
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. The thundery weather may turn into a more widespread rainfall event and if easterly winds get involved and the trough moves onto the coast, we may transition into a heavy rainfall event for the southeast of NSW or eastern VIC. Something to watch.
Tropical Waves - Next Week - December 30th 2021- January 6th 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 30th 2021 - January 6th 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 - Next video due out at 9am EDT Friday.
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days
The pressure pattern has remained volatile in the short and medium term with widespread falls contracting out of the north and east of the nation. The bulk of the nation looking settled through NYE and into early next week before we start to see a shift over the eastern and western inlands with a troughs working down both sides of the nation. The moisture levels are expected to deepen over the east and west and it will be a matter of position and scale of the low pressure which will determine rainfall spread. The complex nature of the monsoon up north is playing havoc with the overall guidance from about 5-7 days out into the medium term so there is no point in changing the forecasts from this morning.
00Z GFS - Precipitable Water Values - Next 16 Days
The precipitable water values are expected to remain very low confidence at this stage with the data from run to run very poor. We are seeing very challenging differing data sets coming through the nation, with this latest run trending drier where the north of the nation is sitting in seasonal conditions.
00Z CMC - Rainfall Accumulation - Next 10 Days
The forecast confidence is low on rainfall totals across the multiple agencies as we move through the next couple of days, so be aware, the frustrating wait continues for better guidance.
00Z GFS - Rainfall Accumulation - Next 10 Days
As per the CMC the rainfall confidence is very low nationwide, and changes drastically from run to run.
00Z GFS - Rainfall Accumulation - Next 16 Days
As per the above.
More coming up from 9am EDT Friday.