SA - OVERNIGHT SHOWERS AND STORMS CONTINUE TO IMPACT COASTAL AREAS TODAY.

A gusty night of weather with areas of light rainfall spread east overnight and showery bands started moving through the EP and YP early this morning with squally winds and pockets of small hail and thunder.


The cold air field is less intense as the previous system, but will still bring the chance of gusty winds and small hail today, especially through the southeast areas. A few locations could exceed 5mm today down through that region, but the air is much drier so rainfall totals will not be as widespread.


Damaging Winds Risk.

The damaging winds will likely clear from the west this morning and inland areas, while breezy are likely to see moderation by this afternoon and the blowing dust will ease as well. The highest risk are with the squally showers and storms over coastal southeast districts.


The winds veer into the northwest during Thursday clearing skies, before those winds yet again strengthen to reach gale force ahead of the next system. That system will bring another band of light rain and showery weather to follow for mainly coastal areas and the southeast where the better falls will be found Friday night and Saturday.


Temperature Anomalies Saturday.

The temperatures over inland areas north of Coober Pedy to Yunta, could top 30-33C with the desert air being transported southeast ahead of the next front. A sign of the times, with a moderate chance that ahead of the next major rainfall event in mid August, that the temperatures could spike well above the average.


Sunday the weather dries out for most areas, with the airstream again tending northwesterly. There does not appear to be much rainfall for anywhere away from the coast with this feature.


Another front is due Monday and another Tuesday with a colder shift possible, the winds turning southwesterly with a dry airmass to follow. The rain band on the front that shifts the winds into the southwest may be moderate and extend further inland.


Lets have a look at modelling


12Z GFS Surface Pressure Pattern for the coming 16 days

The pressure pattern continues unchanged for the coming 5-7 days with the westerly wind belt continuing, however the ridge is now starting to beat down the intensity of the westerly winds, so while there are cold fronts impacting southern parts of the nation, inland areas are starting to see less rainfall from the weekend. The winds veer more northwesterly and we are seeing the upper air become more stable under the ridge. The ridge looks to sit further south for the week of August. There are signals that the weather may begin shift from mid month as we have been looking at, which still seems to be a fair assumption at this time as the westerly begins to retreat south.

12z GFS Rainfall for the coming 10 days

Rainfall becoming lighter which is expected under the pattern shift. So the further north you go, the less rainfall you will see, a bit like what interior parts of SA and NT has been experiencing. The further south you go, the weather will be damp, but not as wet as recent weeks. The best rainfall will be for any region exposed to the westerly wind regime. There may be even lighter falls now for the northern EP with the weather drying out.

12z Euro Surface Pressure Pattern for the coming 10 days

The pressure pattern is starting to become less dominated by the long wave troughs throughout the outlook with a high pressure belt now starting to dig into the westerly belt. So while there are still frontal incursions through southern parts of the nation, they are less intense, less frequent and are producing less rainfall. Note the ridging over the southern states towards the end of the outlook which supports the shift in the upper level pattern. That will also move the moisture around and reorganise it over the northern and northwest of the nation, setting it in a position that favours better rainfall odds from mid August.

12z Euro Rainfall for the coming 10 days

Rainfall rule applies the same as GFS, the further north you go, the less rainfall you will see and the warmer your weather will be through the period, and the further south you go and if you are along the western slopes, the more rainfall you will see, but overall it looks to be half of what has been experienced in previous weeks

12z Euro Precipitable Water Anomaly for the coming 10 days

This is the more interesting product, the moisture that is rolling through the nation. Now while the moisture content is high, it is not producing a lot of rainfall outcomes just yet, however this could change as the moisture starts to pool in unstable hot air over the northwest of the nation from mid week. You can see the moisture then surging south and southwest through the western interior of the nation towards a large cold front and upper trough which would then form a larger rain event from mid month. Again medium term forecasting carries low confidence and we will again classify this as a signal but certainly one too watch.

Rainfall for the next 10 days

Rainfall is starting to come down as we see more systems that have gone through than what is ahead of us, which is the first time in about 4 weeks where there is drier weather to come. High pressure will develop over the southern interior of SA with the weather expected to settle down during the coming 7 days, though there will be fronts, they will not be as intense and not bring much as rainfall inland. We will keep an eye on the moisture over northwest of Australia during the next week to see if that can creep southeast into mid month.

More weather details to come.


19 views0 comments