NATIONAL WEATHER WRAP EVENING EDITION - SATURDAY 28TH OF AUGUST 2021.

Headlines


  • Showers and storms breaking out through northeast QLD with a weak trough.

  • Showers and a few thunderstorms through the southeast of Australia tonight and Sunday with a trough and low pressure system passing through to the east.

  • Warmer weather developing next week with above average temperatures for most states.

  • Stronger system approaching from the west during mid next week, which will be the focus of widespread rainfall developing across the nation.

Certainly looking at more unsettled weather passing through the southeast this evening and overnight into Sunday. We already have scattered showers and a few thunderstorms rotating through eastern SA and into the Mallee tonight and through Sunday morning. The coverage will become much more widespread during Sunday over eastern VIC and into southeast and southern NSW.


You pick the high pressure ridge that is over the north and the west of the nation with clearer skies and dry air. One low is off the coast of NSW and another is on the approach through SA and VIC this afternoon, overnight and passing through southern NSW during Sunday.

The airmass over the east of SA is rather unstable this afternoon and a few thunderstorms have broken out through the Riverlands and into the Murraylands as well, mainly middle level with brief moderate rainfall. These will push into northwest VIC this evening and over southwest NSW overnight.

A weak trough over QLD is expected to see widespread showers develop along the coastal fringe and inland along the trough itself, showers and thunderstorms are possible. You can see that moisture surging through the eastern parts of QLD today and that may be extended southeast and south through the coastal fringe and adjacent inland east of the divide with some showers and thunderstorms expected from tomorrow through early next week.

Thunderstorms are possible tonight and again through tomorrow with a very low risk of organised severe weather at this time.

Day 1 - Remainder of Saturday.

Day 2 - 12am Sunday to 12am Monday.

Temperatures this afternoon have been milder than recent days and the air is starting to warm up over northwest Australia, which will be the breeding ground for the warm air that is drawn southeast through the coming few days ahead of the strong cold front mid to late next week.

The weather next week headlined nationally with the big warm up passing through the southern and eastern parts of the nation with a northwest flow developing. This will lead to significant warm up with many locations heading towards 30C or more! But do note that it won't last for the entire outlook with a heads up the spring roller coast ride in temperatures set to plunge the nation back into below average weather for the second week of September.

Out west from mid week a large scale cold front will move through and strengthen as it approaches SA. The system still expected to form into a low pressure system somewhere between SA and NSW at the moment, and the timing of that will become more clearer as we get through next week.


The rainfall could become widespread and heavy on the current guide, with warm to hot air clashing with the colder air over WA that spreads east, with moisture feeding into this zone, once again ingredients are there for another major rainfall event.


00Z GFS Surface Pressure Pattern for the coming 16 days

The pressure pattern continues to show no change for the coming 2-3 days, the active weather over the northeast of QLD with showers and storms and a few showers and storms over the southeast with a clearing trough, otherwise it is settled throughout. The main focus is the very warm weather developing over the course of the next 5 days. Some areas could get into the 30s over multiple states which is quite warm for early Spring. Then the cold front of note starts to stand up from Tuesday, passes through WA Wednesday and then onto the eastern states later next week or the weekend. A low is likely to develop along the trough and front as it moves through the southern parts of the nation, where that happens remains to be seen but tonight it has it over the southeast inland of nation. That will see widespread rainfall over multiple states, the potential for a month's worth of rain where the low forms is quite possible.

00z GFS Rainfall for the coming 16 days

The major shift in modelling on rainfall has been with the focus of rainfall moving to VIC and southern NSW with the system passing through the south of the nation next week. The west and most of SA should see reasonable falls, but dry weather for the inland. Then we track that system over the eastern inland and perhaps showers and thunderstorms extending through NSW and into QLD as the colder air surges north and east. Medium term, looks quiet but there are systems out there, but for now the main focus is the system mid to late week for all the southern states.

00z GFS Precipitable Water Anomalies next 16 days

This paints the picture surrounding the moisture moving over QLD early in the week producing those showers and thunderstorms near a trough. That trough then weakening and moving away allowing a high to send a northeast to easterly flow over the northeast of the nation, that spreads moisture through the western parts of QLD into Central Australia. It is here that the front will likely to run into that moisture and push it back over the east with large areas of rainfall. Another shift in the moisture spread tonight and from this morning has been the larger injection of moisture coming in from northwest WA which could lead to a band of rainfall spreading through western SA and outback WA too. Moisture in the medium term builds over northern parts of the nation which could lead to unsettled weather for the tropics.

Rainfall for the next 10 days

Not much change in the forecast from this morning, with showers and storms over the northeast of QLD spreading through central areas early next week before the trough dissolves. A weakening low will spread showers and storms over the southeast during the coming 24hrs. Then we watch the main frontal activity from mid next week which offers some hope of inland rainfall returning to much of the south and east, but again don't get too caught up in all the modelling as it will chop and change.

I will have a detailed medium term forecast due out tomorrow, more of your state by state forecasts and for southern and eastern areas, widespread rainfall is on the cards as is well above average temperatures.




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