And that is thanks to the shift in modelling tonight to take a low pressure system through NSW into QLD later in the outlook, but the confidence in the medium term is low.
Lets look at the short term and we are tracking a mild night as a warmer airmass descends over the state. A westerly airstream is beginning to freshen ahead of a cold front that is passing through the southern states. That is assisting in bringing temperatures well above average into Wednesday.
A very warm Wednesday coming up ahead of the front passing through the southeast of the nation, that will see some centres into the 30s for Wednesday afternoon. Temperatures come down during Thursday and Friday.
The front and rainfall likely to stay south of the border with the system moving east, however the surge of southerly winds on the northern flank of the front will create an area of convergence over the border with NSW with showers increasing about the southeast of QLD. This may extend further west of the divide over the weekend. There could be a couple of moderate falls in this zone.
Watching the boundary moving north through NSW, as that may start to lift the moisture over southern QLD during the weekend while showers increase along the coast in easterly winds.
Next week the showers increase further along the FNQ coast as the trade winds increase. We have an upper low mentioned above that looks to bring a parcel of unstable air further east and this lifting the moisture over the eastern inland of NSW and QLD. This morning it was much more widespread on the modelling, this evening, not so much.
Beyond that system you can see more rainfall opportunity for the second half of August.
Lets look at modelling.
00Z GFS Surface Pressure Pattern for the coming 16 days
The pattern for the coming few days is still locked in from this morning, no real change in the passage of frontal weather over the south, nor the change in the cooler weather spreading through the southern states. We will see the west clear out later this week with high pressure moving in. In the east, a boundary may form over the NSW/QLD border with the widespread showers moving inland, thanks to the approach of a trough. That trough will pass through WA on Saturday and race east to be over the eastern inland during early next week, providing more support for the weather to turn showery. The medium term still offers widespread rainfall as you can see the in the accumulation below for mid month.
00z GFS Rainfall for the coming 16 days
Rainfall moderate along the front in NSW tomorrow, but for the remainder of the east it looks like light falls at best if anything, here in QLD perhaps a light shower about the border. Inland areas will dry out with a high nosing in. Then the easterly winds return, shower are expected to develop along the east coast. That shower activity could increase through the weekend into next week with an upper trough passing through adding more spice to the atmosphere, supporting more convection and moderate rainfall. That may extend inland. Then you see another strong system, just passing to the south but that is low confidence. Above average rainfall may occur over tropical areas along the east coast and NT.
00z GFS Precipitable Water Anomalies next 16 days
The PW values largely unchanged in the short term and you can see that verifying in real time looking at the satellite imagery. There is a lot of moisture coming into NSW from the north as well via a easterly flow over QLD which has transported a parcel of deeper moisture through the inland, that moisture expected to link up with the cold front to see a band of rain developing along the front as it passes through the east. Then we watch the moisture build next week, via easterly winds and a boundary over the QLD/NSW border, over the tropics which will surge south and southeast via the upper level winds and another plume of moisture coming into the tropics from the east via the trade winds. Where this moisture is picked up by the low pressure remains to be seen.
00z Euro Surface Pressure Pattern for the coming 10 days
The pattern for the coming 5 days in good agreement with most global models so that makes the first half of the forecast fairly easy. The second half of the short term period below is volatile and hard to pin down the impacts of the moisture and the low pressure coming through the southern parts of the nation and that will continue to be the case for the next few days.
00z Euro Rainfall for the coming 10 days
Rainfall most widespread through the coming day with the front passing through the southeast states with a burst of showers and some thunder. The moderate falls reserved for southeast NSW with the front interacting with moisture. That boundary stalls over the southern border with showers increasing for northeastern areas of NSW and southern inland QLD as well as along the coast north of Sydney. Then we track that upper feature over SA this time next week, it offers a decent chance of the next rainfall event. But the specifics are too hard to pin down at this time, but you can see the difference between GFS and Euro tonight.
00z Euro Precipitable Water Values next 10 days
The PW values again from run to run are all over the shop in the medium term making it very tricky to find any consistency, but the ensemble data is more settled and show moisture increasing through northern and eastern parts of the nation during the middle of the month. So while you are looking at all your weather apps saying nothing, they don't pull ALL the data that is available out there. So the forecast while it looks benign on the Euro, there are signals in the broader data sets that suggest otherwise. For now there is that first system to watch this time next week which may offer rainfall from SA through VIC and NSW after bringing showers this weekend to the west coast.
Rainfall for the next 10 days
Showers about the FNQ coast will begin to ease overnight and Wednesday as the wind regime relaxes. Otherwise it is a hot and dry few days for the inland as a southwest to southeasterly change begins to move north. That may be the focus for scattered showers this weekend while the coast sees an increase in showers developing over the weekend and through next week again. Moisture deepening over the northern tropics may see showers increasing through the weekend into next week with hot and humid weather building. Also keeping an eye on an upper trough emerging out of SA next week to see if that can trigger some rainfall for southern QLD.
More weather tomorrow.