NATIONAL WEATHER PICTURE - PM EDITION - FRIDAY 23RD OF JULY 2021

Headlines


  • A cold rain over inland NSW with light falls and a few moderate falls across the Central Tablelands today.

  • A cold front approaches the east kicking out the low pressure system and bringing about a burst of vigorous winter weather.

  • More severe wind events likely for the south and southeast next week with the westerly wind belt continuing.

  • Rainfall chances coming up once again for all southern states with the persistence forecast ahead.


National Satellite Picture - Friday 23rd of July 2021

Satellite shows the movement and progression of the area of low cloud and higher moisture levels with light rainfall over the southeast and eastern inland, as a low weakens and opens into a trough. The barrage of wintry fronts clearly evident on the satellite this evening with a deep layer of cold air to ride up and engulf southeast Australia on Saturday afternoon. The rest of the nation fairly fine, a few showers with those fronts in southwest WA are scattered and not overly dramatic.

Temperatures -Friday 23rd of July 2021

Temperatures show the role of that jet stream over the central parts of the nation, very hot in the north with some areas closing in on 40C this afternoon, over the central areas of the nation it is warmer than normal with a dry airmass. Over the southeast colder than normal with light rainfall and thick cloud cover. Spot the front well south of the nation with a defined sharp temperature drop approaching.

38C at Daly River Roadhouse and Police Station this afternoon! A sign of the times!

Radar - Friday 23rd of July 2021

Rainfall is widespread in the east from southeast QLD into northern NSW and into the southeast and ACT. Light falls for the most part but somewhat steadier totals have been observed with the low weakening over the area this afternoon. Showers over the southwest with a front that is blasting through southern districts.

The front has some grunt to it and a well defined squall line as it marches east this afternoon and this evening, so those in SA should be watching the weather radar later tonight into Saturday morning.

Rainfall for the next 10 days - Friday 23rd of July 2021

Rainfall for the most part is being left unchanged this evening off current guidance but I have removed the falls from QLD as that situation resolves. The falls over northern NSW have decreased but will leave the light rainfall smear in for the events in around 1 week from now. This will be the focus of future forecast analysis as it could bring rainfall to very thirsty parts of SA, NSW and QLD.


00z GFS Rainfall for the next 10 days - Friday 23rd of July 2021

Rainfall again largely unchanged from this morning however, there are hints of that pattern flip into early August, it has dropped it in the latest run tonight but that does not mean it is off the table. For now the inland dry for the coming 10 days, the southern areas of the nation, windy with showery periods and moderate falls.

00z Euro Rainfall for the next 10 days - Friday 23rd of July 2021

Euro is starting to pick up on that moisture plume next week introducing inland rainfall which is what I have been suggesting may be the case. I would like to see other models get on board with this idea, but there is a chance with the westerly wind dominance over the south, that moisture from the Indian Ocean may be drawn into the southern inland of WA through SA, VIC and into NSW. Hot and dry over the north.

00z CMC Rainfall for the next 10 days - Friday 23rd of July 2021

CMC very similar with the rainfall spread identical to GFS however, note the moisture plume and rainfall over the northwest Indian Ocean and the moisture building showers and storms to the north of the NT, that is the moisture source that I fully expect will come down and produce the pattern flip in 2 weeks. For now, more of the same wet in the southern third, dry and hotter the further north you go in dry season conditions.

Model discussion and analysis


00z GFS Upper Air Pattern and about 18000ft - Friday 23rd of July 2021

The pattern is pretty much locked in for the coming 10 days with about four waves to pass through with gusty winds, and showery periods for the southern states. The northern and eastern inland mostly dry under the upper high. Then we see the upper high break down over northern Australia and the heights begin to fall into the first week of August, this allowing more unsettled weather to develop, but the modelling cannot render that far out with any great specificity so again a signal for the pattern flip is still active for the second week of August.

00z GFS Surface Pressure Pattern and Rainfall - Friday 23rd of July 2021

The surface pressure pattern also largely unchanged with the westerly wind regime producing widespread showers over southern coastal areas of WA through to VIC. Some of the rainfall coming into inland areas of these states but this will become clearer as each system evolves in real time. For now it is a persistence forecast for the coming 10 days. Then the weather looks to shift around the 5-7th of August.

00z Euro Surface Pressure Pattern and Rainfall - Friday 23rd of July 2021

No real change in the pressure pattern in the coming 10 days however we are now starting to see the upper trough at the end of the sequence interact with that moisture plume and to bring up the chances of inland rainfall. The Euro stands alone in this for now but I do suspect as I have kept on saying that the models will come into agreement with this over the coming days.

00z Euro Precipitable Water Values - Friday 23rd of July 2021

The moisture values are increasing next week particularly from this time next week into the weekend with a large cloud band developing and this leading to areas of inland rainfall, if this verifies. But the weather for the coming 7 days dominated by the westerly wind regime.


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