NSW - WARM AFTER FROST - SHOWERS FRIDAY FOR THE SOUTH.

Another cold start for much of the GDR with local frost patches about the ranges and some adjacent slopes areas, the frost is the last in the sequence for the region with high pressure moving east, the warmer air moving in and plenty of sunshine for Thursday.


Temperatures down as low as -3C this morning through the southeast inland once again, but the air is warmer over the western inland as the flow tends into the northwest, so plenty of sunshine in a dry airmass.

A dry airmass keeping much of the nation dry and that extends over the northwest of Australia where the southeast winds continue to work with sinking air meaning things are nice and quiet. You can see the set of fronts which are expected to pounce on the southern states this weekend, the main front moving through Perth and the SWLD this morning.

A cold front is expected to slide southeast during Friday producing scattered showers and a thunderstorm over the southeast states, some of that may creep into the south of NSW during Friday afternoon and evening as the front rolls through to the south.


The weather clears during the weekend and temperatures warm even further during Sunday with the warm air drawn in from the west and northwest ahead of the stronger front due in early next week.


Temperatures up to 9C above average over the northern inland of NSW during this weekend, some stations likely to hit the low 30s

That front will bring a colder shift in conditions during the early part of next week so once again it should be noted there may be some issues for those grazing stock at the moment with a significant period of warm weather followed by some very cool air on Monday night.


The major impact from this system is expected to be in the temperatures that fall throughout the nation. Falling by 3-5C below average. Some locations could see a 15-18C temperature difference between the weekend and early next week.

The medium term will offer more twists and turns - I do update sometimes before 10pm and last night you would have seen that the models had started to increase rainfall for the east with a low pressure system and easterly wind dominance, well that has softened again but there is more low pressure systems floating around and moisture being drawn in from the northwest and northeast of the nation.


12Z GFS Surface Pressure Pattern for the coming 16 days

The first of the cold fronts are passing through the southwest of the nation today already triggering a few showers and thunderstorms as it passes through. The lead trough that brought the storms to WA overnight is now bringing a few showers through western SA today. The weather dry elsewhere and the big impact is the well above temperatures ahead of these fronts over southern Australia during the next 5 days or so. Next week we have a major front passing through the southeast, that sends a pulse of colder air throughout the eastern inland of Australia bringing a period of below average temperatures from Monday through Wednesday. Over the north there will be waves of dry air replaced with moist air racing from east to west during the next week or so. That may spark scattered showers over FNQ and over the far north of the Top End. The medium term as you can see still holds the chance of follow up rainfall for the southern and eastern states, which I will cover off more later this morning.

12z GFS Rainfall for the coming 16 days

Rainfall over the southwest of the nation today through the weekend will bring moderate falls for the SWLD, the rainfall from those fronts reaching SA later today through Friday afternoon and VIC and southern NSW during Friday afternoon through Saturday morning with mainly light falls. The front being forecast to fall southeast now and the moisture dragged on it's northern flank decoupled from the front, meaning more cloud than rainfall. The weather then turns drier over the western inland of the nation with high pressure, that high pressure helping to propel that next major front over the southeast states with a band of rain developing later Sunday through early Monday with VIC and southeast inland NSW picking up the best of the rainfall and that rolls up the GDR. Then the weather becomes lower confidence and you can see more rainfall rolling through the east of the nation and again another stronger front coming through the west of the nation, do the winds go easterly as well for QLD and NSW? This remains up in the air.

12z GFS Precipitable Water Anomalies next 16 days

The PW Anomalies show the movement of that moisture coming in from WA today bringing the patchy rainfall and storms through the region, that moisture is attached to the front passing through the southwest today, but when the front comes past SA and into the southeast states, the rainfall is much patchier with the front sliding further away from the nation. Note the front coming in later Sunday into Monday over the east, that provides a better chance of rainfall as the front is running into the moisture over the eastern inland allowing for more widespread rainfall to develop. The southwest of the nation turns drier with a dry airmass, you can see the moisture running over the tropics throughout the period and the impact of the winds trying to turn easterly through the medium term pumping in that moisture over the eastern states. Systems running from the west into this moisture would see rainfall become widespread over eastern Australia, but it needs to actually happen in reality, and not just on paper, but the idea is there.

12z Euro Surface Pressure Pattern for the coming 10 days

The pressure pattern is unchanged for the coming few days which means it is likely that what is in the forecast packages now will stand. Warm to hot over the eastern inland spreading through the south and southeast ahead of the frontal weather passing over the southern parts of the nation. The southwest of the nation clearly the wettest part today with a front rolling through, that front loses integrity over the southeast this Friday into the weekend, but it will help to bring in a warm to hot weekend. The stronger system is Sunday and compared to GFS, this model runs the front through quicker and with less rainfall likely over the east and southeast. But it will be cold! That is a high chance. Beyond that front, you can see the moisture over the Tasman Sea interacting with that colder air, allowing a low to form. The nation turns dry and benign this time next week, where GFS is a little more unstable.

12z Euro Rainfall for the coming 10 days

Rainfall is less than last nights model run nation wide, that is thanks to the drier air ruling in this run, where last night there was more moisture to work with and the weather system later Sunday into Monday moved more north than east, which you can see in todays run. So that sees less rainfall for the east and south. Over in WA, the numbers have come up for today's system as the model recognises that the clash of the airmasses and moisture involved will allow for more widespread rainfall than first charted. Then the modelling is fairly quiet next week as a cold stable dry airmass runs through the nation.

12z Euro Precipitable Water Values next 10 days

You can see the impact that dry air has on the rainfall chances nation wide, with a large dry surge expected early next week, sweeping out the rainfall chances and cloud cover, leading to not only below average temperatures, but clear skies and a heightened frost risk for most states. The moisture tries to return later in the run with a front coming back through WA and that may introduce moisture from the Indian Ocean. Note the absence of easterly winds as per the GFS and how that impacts the moisture levels across the nation. This forecast package is still low confidence and it will continue to chop and change.

Rainfall for the next 10 days

The weather is largely unchanged rainfall from last night, the first system coming through tomorrow afternoon and evening, perhaps not bringing as much rainfall with the front slipping another 100km further south in the modelling, but will track that trend this afternoon. Clearly the wettest weather is associated with the front passing through Sunday night through Monday. There may even be snow for some parts of the GDR during the early part of next week too! Then drier weather developing over the inland with a colder airmass surging north. Showers may develop along the coast with a southerly or southeasterly flow mid next week. A front approaches later next week from the west.



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