NATIONAL WEATHER WRAP FOR THIS SUNDAT 25TH OF JULY 2021

The persistence forecast continues for the nation, with the frontal weather for the southern states and fine under an upper high over the north. There are signals for inland rainfall chances to increase in the medium term and the pattern to also flip in the medium term.


Lets take a look at the state of play.


National Satellite Picture - Sunday 25th of July 2021

The cold airmass that has been blasting through the southeast states is on the way out tonight but the air is starting to become moist, so the low cloud over inland areas will persist with areas of light rainfall and drizzle tonight. For coastal areas, moderate showers will continue for southern and mountain VIC and southeast SA and heavier falls for TAS. The next frontal system can be seen offshore the southwest of WA, with moisture sitting through the north of the front. Fine, clear and dry over the north and northeast.

Temperatures - Sunday 25th of July 2021

Fairly seasonal for late July, with a cold airmass keeping temperatures below average, otherwise most of the nation is seasonal, but much hotter weather is being experienced over the north of the nation with the strong upper high.

How about 4-5C about southeast NSW this afternoon with sleet falling? Bitterly cold conditions continue but the winds are starting to moderate. Warm air advection is starting to see warmer air coming into the EP as the flow turns northwesterly.

Radar - Sunday 25th of July 2021

The wettest part of the nation is about southeastern Australia with the frontal weather passing through over the coming 24hrs and the onshore flow is cold and unstable. There is a wave in the westerly flow that has brought moderate rainfall into eastern SA and western VIC today and that will spread through northern VIC and into southern NSW tonight with light falls. Dry most elsewhere, though cloud is thickening back over WA with the approach of a front and the moisture feed from the Indian Ocean.

Rainfall for the next 10 days - Sunday 25th of July 2021

Frontal weather for the southern parts of the nation for the coming week will keep the majority of the wet weather over the southern states as has been the case for a number of weeks now. The weather over the north will be mostly dry, clear and hot. The warmer weather may tend a little more humid next week as the airflow starts to turn easterly.

00z GFS Rainfall for the next 16 days - Sunday 25th of July 2021

Rainfall is largely unchanged for the coming week, that persistence forecast is reasonable and so what you have experienced outside during the past week, more of that is to come this week. For next week, that pattern looks to settle down and the frontal frequency will also be reduced as the westerly winds retreat south.

00z Euro Rainfall for the next 10 days - Sunday 25th of July 2021


00z CMC Rainfall for the next 10 days - Sunday 25th of July 2021


Model discussion and analysis


00z GFS Upper Air Pattern and about 18000ft - Sunday 25th of July 2021

The upper air pattern is fast flow and zonal, with embedded cold fronts in the flow bringing the wet and gusty conditions to most of the south, that will be from WA through SA, VIC, TAS and southern and central NSW. The upper high over the north keeps things dry and settled with above average temperatures. That may start to break down next week with a reduction in the temperatures as the upper heights reduce.

00z GFS Surface Pressure Pattern and Rainfall - Sunday 25th of July 2021

The fast flow pattern means the fronts will keep on coming for the south of the nation, but the northwest flow ahead of some of the fronts may offset some of the colder impacts with warmer days expected with the winds tending northwest to northerly at sending in the warmer air. The moisture involved with each system will increase with each passage. We will see the most widespread rainfall associated with the frontal weather coming through during Wednesday into Thursday then into Friday and Saturday. There has been some model guidance to suggest the rainfall may extend inland along an upper trough over SA, NSW and maybe even southern QLD. We will wait and see.

00z Euro Surface Pressure Pattern and Rainfall - Sunday 25th of July 2021

The fast flow pattern is set to continue for southern parts of the nation with as you can see much of this week. That means more gales and showery periods for the southern states. The north relatively dry with increasing temperatures for QLD with perhaps some cloud increasing over the weekend. You can still see multiple rain bands trying to develop over the eastern and southern inland during the course of the outlook, so there is some promise for rainfall over inland parts that have missed out or follow up for other areas.

00z Euro Precipitable Water Values - Sunday 25th of July 2021

PW values are quite high for a westerly wind regime with more rainfall expected with the frontal weather than what we would normally see during this time of year. Keep an eye on that moisture later this week as there could be extensive cloud developing and rainfall developing from the northwest through the southeast. The rainfall may also develop over eastern inland areas of QLD and NSW with a trough and that moisture lingering. But the most interesting aspect that again will be monitored this week, is the moisture that dams through the northwest of the nation.

The Euro is a little quicker tonight in bringing the moisture through the northwest and holding it there in about 10 days before sweeping this down into the south and east, which is something to also consider. But there is a lot of moisture further west of the nation as you can see below after this period that needs to be monitored. We can see the moisture now increasing further as the north of the nation warms further.

18z GFS Precipitable Water Values - Sunday 25th of July 2021

This is the pattern flip to watch into the second week of August, which I have spoken about earlier today. These high level moisture content will come into play at some point during mid August for large parts of the nation.


Saturday 7th of August 2021

Monday 9th of August 2021

Note the moisture coming southeast and south ahead of the cold front


So there is plenty on the horizon for the week, the pattern is the same for much of this week, but it is what is lurking over the north and offshore in the Indian Ocean that has my interest for the second week of August.

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