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

Headlines


  • Areas of light rain and thick cloud cover over much of NSW today with light rainfall over the southern inland of QLD.

  • Fine weather returns to SA and VIC though cloudy, however frontal weather is beginning to stand up in the Southern Ocean.

  • Showers developing for the southwest of WA today with that first front, begins the sequence of a wet week.

  • And you guessed it, fine and hot and so dry over the northern parts of the nation under an upper high but gorgeous dry season weather.


National Satellite Picture - Friday 23d of July 2021

The low pressure system over the east is on the way out to the Tasman Sea over the coming 12 hours. The weather clearing from west to east through the coming day, however a fast moving frontal boundary is expected to sweep through the southeast during the weekend with widespread showers and cold weather blasting through. There is a severe weather risk for farmer and graziers with this event and damaging winds also possible.

Temperatures -Friday 23d of July 2021

A seasonal morning across the nation, with the colder weather dammed under cold rainfall in the southeast. Warm over the north but perfect dry season conditions. The weather mild over WA this morning with winds freshening ahead of that first cold front passing through.

Temperatures clashing over QLD, a sign of spring time building over the northern parts of the nation, this is where we will see weather become active once moisture and lifting mechanisms come into play. But the spring shift is already underway.

Radar - Friday 23d of July 2021

Rainfall active in the east and the southwest of the nation, some better rainfall for southern QLD than what models had forecast which is good news. The rain in the east is mostly light and patchy as expected and will slowly move east. Showers increasing over WA and into the Bight with light falls for WA today. Fine and dry for the southeast ahead of the fronts today.

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

Rainfall largely unchanged with the westerly winds in full swing keeping the frontal weather active for another week. The northern parts of the nation dry away from the QLD coast. I have kept the rainfall over the inland areas with moisture increasing over the west of the nation, I do expect this will move east later next week in some form.

12z GFS Rainfall for the next 10 days -Friday 23d of July 2021

Rainfall again largely unchanged for the coming 10 days over the course of the next week, but there are signs that the rainfall could increase over inland WA then spreading towards the east with the frontal weather standing up in the Bight with evidence of a strong upper trough. So that may introduce rainfall into inland SA later in the sequence which is not quite shown here in modelling but I am leaning towards that changing in the coming days. Dry weather for the northern two thirds, may also start to change in the coming week. Keep an eye on the moisture in the Indian Ocean.

12z Euro Rainfall for the next 10 days - Friday 23d of July 2021

The showers are expected to be heaviest over western TAS and WA as well as along the NSW and VIC ranges this week with that westerly wind regime. Once again as per GFS, keep watching the moisture profile over the inland areas of WA as that tracks eastwards next week with the rainfall spread creeping inland over SA and into NSW and QLD later in the sequence a plausible solution.

12z CMC Rainfall for the next 10 days - Friday 23d of July 2021

Very similar spread to the other models as you can see above, but the pattern may begin to shift towards early August if this is correct. But I think this model is a little too dry.

12z KMA Rainfall for the next 12 days - Friday 23d of July 2021

Just beyond the 10 day period, some of the models are suggesting that pattern flip with rainfall spreading north and east which would see rainfall come back into SA, NSW and QLD if this was right. This would place that pattern change during the second week of August. I will have more on that later.

Model discussion and analysis


12z GFS Upper Air Pattern and about 18000ft - Friday 23d of July 2021

Upper air pattern again is largely unchanged with the westerly wind belt in full swing, but note that in the second week, we are stating to see signals of the pattern breaking down with the heights coming down over northern Australia and the heights coming up over southern Australia which could lead to a shift in where moisture will go, rainfall chances will likely shift around and temperatures warming up over the nation. This will become clearer this time next week as we get better data. But for now it is a persistence forecast for the coming week at least.

12z GFS Surface Pressure Pattern and Rainfall - Friday 23d of July 2021

The surface pressure pattern and rainfall distribution shows that this week is largely unchanged. That will see more frontal weather sweep through the southern parts of the nation. Some of that could be quite productive with moisture surging out of the northwest. That will also become clearer by Sunday or Monday as we get closer. Frontal weather then becomes suppressed and note the change in the pattern as we get to the end of the first week of August.

12z Euro Surface Pressure Pattern and Rainfall - Friday 23d of July 2021

As per the GFS no real change in guidance so again persistence forecasting applies, what you have experienced this week, you will have that for another week. But again watch the moisture over WA with that moisture possibly moving south and east during the coming week, and can that moisture be in phase with the frontal weather sweeping east.

12z Euro Precipitable Water Values - Friday 23d of July 2021

We will be watching this closely as well, the PW Values are very critical to widespread rainfall but even moreso is can it link up with frontal weather? And again at the end of the run, some of that moisture comes into QLD and the southern NT which is a shift in conditions.

12z Euro Simulate IR Satellite next 10 days - Friday 23d of July 2021

Watching the systems mid to late week, the cloud bands are increasing in size, but can some of this sneak into northern NSW, SA, QLD during the period? Not impossible.

More to come today.

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