QLD - PATCHY RAIN AND STORMS OVER THE SOUTH TONIGHT, COOLER AND DRIER AIR SURGING NORTH

A strong cold front is passing through the southeast and has triggered rounds of showers and thunderstorms and a warm airmass ahead of that in a northwest flow.


The most robust weather is currently sweeping through the southeast and south of the state along the cold front and trough. Dusty skies have been observed over far western parts of the state today as the colder drier southerly surged north.

There are still scattered thunderstorms in progress over much of the state and they are marching eastwards.

The rainfall totals have been light but welcome none the less for many areas, seeing not much rainfall since about the first parts of July. Some areas of the inland have received 10mm today.

Thunderstorms are more likely over the southern half of the state closest to the NSW border. There may be gusty winds with these storms this evening and overnight before they clear during the morning offshore.

Rainfall will contract south and east during the coming 24hrs as the front passes through and a low forms on the front offshore the east coast of NSW. That will be where the heaviest of the weather will be in the coming days.


Over much of QLD, cooler air surging north means drier weather, with sunny skies, temperatures remaining below average for this time of year. The temperature drop could be as much as 15C in some locations.

Later in the week, the tropical moisture will surge south, lured in by a developing low in the Bight, and it opens up the door for a rain band to develop somewhere over the east and south of the nation so that will be one to watch for QLD. Lets have a look at that through modelling.


00Z GFS Surface Pressure Pattern for the coming 16 days

The major rainfall event is ongoing over the east. From mid week we will see the low pressure system that forms begin to move off to NZ and this will allow the high ridging in over WA and through SA to move further east, opening the door for frontal weather to pass in over the nations west. Rainfall will ease over the east and develop out west. The dry air should surge through the north clearing out the humidity for a period. Later in the week a front will approach SA but turn into a low pressure system before it slowly advances eastwards. Moisture is likely to be pulled south through QLD into NSW with a trough developing over the eastern inland, this could see widespread rainfall redevelop for the east with heavier falls for QLD with a trough hanging over the east coast. That rainfall could persist for a number of days. The rainfall lighter through SA and VIC but milder weather will make it feel spring like. Then we will track the low over the Bight through Tasmania, and weakening. Another front is likely to launch over WA through the early part of next week and that may bring yet another burst of rainfall to the east and south into early September.

00z GFS Rainfall for the coming 16 days

Showers about the east tonight clearing further away by morning. The weather over the remainder of the nation is likely to remain dry with a cooler airmass. The next lot of rainfall is expected out west during Thursday with moderate falls. That system will help to initially kick out the low off the east coast but then bring the low pressure from the west through to SA introducing follow up rainfall for the southern and eastern states. The rainfall for QLD could be quite heavy over the weekend into next week. The west will see another cold front during early next week and that will advance east once again.

00z GFS Precipitable Water Anomalies next 16 days

You can track the drier air coming in over the southern and eastern states with a cold southerly flow developing. That southerly flow is expected to sweep throughout large parts of the nation and flush the humidity out of the tropics mid to late week. Another surge of moisture will develop over parts of WA and this will run across the south of the nation with a low pressure system forming in the Bight. That low will also help to drag moisture from the northeast and north and filter through the eastern inland, feeding a trough over the weekend and next week. More moisture runs through the nations north and this may increase values over WA and then feed frontal weather passing over southern Australia.

00z Euro Surface Pressure Pattern for the coming 10 days

The pattern is largely unchanged from this morning. Euro is still suggesting the most robust weather will be connected to the events over the south and east during the next 3 days or so. Then the frontal weather returns over WA from mid week, this may help to push a high east, which then knocks the low pressure system out to NZ. The quicker this happens, the more likely we are to see rainfall spread from west to east over the nation, bringing follow up rainfall chances for SA, NSW, VIC and QLD. Now the Euro still does not see what GFS does, however that does not mean it is impossible. It does however have a much larger long wave sweeping in from WA later in the period which on this read would create quite a hefty rainfall event in the first week of September.


00z Euro Rainfall for the coming 10 days

Rainfall very similar from this morning. The weather is most active in the short term over the east, mid week over the west, that weather from the west will then come through SA to the southeast states from the weekend with the next chance of rainfall but the moisture that is in place is out of phase where GFS is in phase hence more rainfall. The model now introducing a much more interesting system later in the period over WA that does look spring like, it would lead to widespread rainfall developing later next week.

00z Euro Precipitable Water Values next 10 days

We are now seeing the weather dominated by the high moisture levels today and this has now resulted in widespread falls in the east. The moisture is pushed out of the nation mid week before it returns over the weekend through QLD and the NT and then back over WA as well as the frontal weather ramps up.

Rainfall for the next 10 days.

This forecast is hard to prepare but I am leaning towards the GFS somewhat given the moisture was first picked up by this model before the Euro came on board in relation to this current rainfall event over the southeast. For now the rainfall will be patchier and uneven in distribution during the coming 24hrs. Then we will watch to see if areas of rain return from later this week into the weekend with moderate to heavy falls. So this forecast confidence is still low.

I will have a Climate Update during Tuesday for the coming 4-6 weeks.



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