Widespread showers along a cold front passing through the southern coastal areas of the state are extending north along a boundary this morning, with colder air surging north today. That is bringing up the chance of thunderstorms with hail and gusty cold southwest to southerly winds.
The showery weather begins to clear off during Wednesday with a very weak ridge passing through. This will lead to a cold night into Thursday morning, northern districts will have to watch out for the chance of severe frosts throughout the region.
A weakening low pressure system is expected to sweep through SA during Thursday and enter NSW with patchy rainfall moving into northern VIC with the best of it likely to cross over the Mallee, with some chance, fingers crossed, of some moderate rainfall totals.
The low moves out and weakens over NSW during Friday but another front is set to pounce into the weekend, with again moderate falls. Strong and gusty westerly winds to follow may reach gale force and very cold air associated with this system may bring the chance of low level snowfalls.
Damaging winds and a very high risk to stock will mean that graziers should be on high alert for the system, even though it is later in this outlook.
So with the moderate rainfall we have to consider the frost risk on Thursday morning and the risk to graziers during Tuesday but more likely to be an issue during Saturday and Sunday.
The frontal weather may continue to impact parts of VIC during early next week.
12Z GFS Surface Pressure Pattern for the coming 16 days
The weather modelling is largely unchanged overnight and this morning, so the persistence forecast continues. I was hoping for stronger guidance on the rainfall spread coming in from the west with the low pressure sweeping into SA, the best of the rainfall likely to be connected to the passage of the low over the Mallee and into southern NSW. The frontal weather that develops during the weekend, could bring widespread gales, showers that may be heavy at times with hail and thunder. Snowfalls may also return down to low levels as per today under the sequence. The GFS is colder than Euro. The showers then ease early next week with a weak ridge developing but more fronts will approach this time next week.
12z GFS Rainfall for the coming 10 days
Rainfall looks to be a bit heavier through the eastern suburbs of Melbourne through to the Yarra Ranges and Bunyip regions. A flood watch has been issued for the showery weather today and tonight. Some areas could get 40mm. Then rainfall over the northwest could be quite productive, 10-25mm coming in from SA though the western districts may now drench northern parts of the state into southern NSW, which would be welcome. Then the frontal weather brings rainfall to areas exposed to the west or southwesterly flow with gusty winds, snowfalls, hail and thunder. There is a chance that severe weather may accompany this sequence.
12z Euro Surface Pressure Pattern for the coming 10 days
The Euro also largely unchanged this morning with widespread showers today, that activity clears away Wednesday. But the low pressure system drenching WA today, comes into SA Thursday and that may bring a spell of rain later Thursday through Friday across the north and west before the frontal weather arrives this weekend. The Euro is not as cold as GFS but has more moisture so rainfall could be heavier under this solution, snowfalls also heavy under this solution as the upper level thickness values support snow down to 900m. Then next week more frontal weather approaches, but the Euro again has more moisture coming into the frontal weather spreading east, so we could see rain break out over inland areas before sweeping the east.
12z Euro Rainfall for the coming 10 days
Rainfall heavier along the divide under this guidance over the coming 10 days. Rainfall not as heavy for the northwest like GFS but still reasonable falls expected with the weakening low pressure. But this will surprise, the low pressure systems that track through the southern inland can produce some moderate falls. The frontal weather that comes through the weekend will bring moderate to heavy showers across southern parts of the state, and into Alpine areas. The rainfall could renew flood watches for the areas under watch today. More rainfall approaches next week.
Rainfall for the next 10 days
Rainfall largely unchanged across the region with falls today being deducted today for this afternoons charts. But with rainfall coming in during the day 7-10 window, that rainfall may make up for what has fallen today, so once again you may not see much variation in the charts. But this is typical of winter. Heavier falls may be drawn in for the northwest today if guidance improves around the low pressure and over the eastern ranges with the frontal weather for the weekend.
Frost Forecast for Thursday Morning
And a reminder that with the brief break in the wintry conditions ahead of the low pressure during Thursday afternoon and Friday, a period of clearer weather with cold air aloft will lead to severe frosts over parts of the east, which may be severe for northern VIC.
Snowcast for the coming 10 days.
Heavy snowfalls are still expected for parts of the Alpine region with the best falls along the northwest and western slopes. Some snowfalls still possible away from Alpine areas during today and the weekend coming with some accumulation possible but this will be refined this afternoon.
More weather details coming today - including the August Climate Update later this morning.