The weather remains unstable over the southeast and drier elsewhere, no real change in the guidance for the coming few days as outlined in the short and medium term forecast packages.

We have got the risk of frost again during Friday morning but the risk shifts west as the trough lifts north through the southeast.

Lets get straight into the weekend and next week.

Tomorrow we have an upper cold pool combing with the existing trough to drive showers which will turn to areas of rainfall over the southeast of the state. There may be some surprise low level snowfalls about the southeast inland. Then another system will pass through over the weekend.

You can see the rainfall spreading north through the southeast of the nation with the trough stuck at the moment.

The rotation and development of cloud in the day time heating process is showing the upper level cold pool that is sitting over the southeast. Rainfall is confined to the southeast of VIC.

That system is likely to deliver light to moderate rainfall before clearing Saturday, however we have another system passing through the southern regions of the nation which will be weakening on approach, but likely to run into residual moisture.

The trough will move offshore the NSW coast during Monday and that will allow for a high to develop over the east. A northwest flow will then bring in a much warmer airmass into the eastern inland for the first half of next week.

A strong cold front will develop over WA and then move into the south then southeast by later next week. This will bring the next most widespread rainfall to the region in the outlook period.

Watching the moisture coming in from the east which is imperative to finding where the rain band forms next week.

Next Thursday afternoon.

Longer term there is a lot of weather on some of the global modelling but once again, no matter what you read off this site on the social media pages, it will come and go and the forecast beyond 7 days is useful as a poke to the eye.

00Z GFS Surface Pressure Pattern for the coming 16 days

The pressure pattern shows the low-pressure system off the southeast coast of NSW bringing widespread showers to the east coast of Victoria and southern NSW. There is a trough that has worked north today and that will be the focus for widespread areas of rain during Friday. The weather is set to turn showery over parts of southern NSW and most of VIC on Friday with the trough and associated cold pool lifting out and moving east. The weather over the nation is being controlled by high pressure and that remains to be the case into next week. Coastal areas of QLD is the area to watch with welcome showers and storms forming along a pressure trough that is aligned through the central and northern inland with moisture streaming in from the easterly winds. The weather should turn more humid through the eastern inland next week, the moisture spreading through to central and southern parts of the nation ahead of a strong cold front. That front is expected to send temperatures way above the average over the eastern states. This may add the fuel needed to bring the widespread heavy rainfall so many are after (the not so many that don’t want either). The rain will progress through WA from mid next week, SA this time next week through Friday and then onwards to the eastern states from Friday into the weekend with moderate to heavy falls possible if it all comes together. The tropics will turn humid as the wind profile tends north-easterly over the region.

00z GFS Rainfall for the coming 16 days

Rainfall confined to two events through the outlook period for the southeast states, we have the low-pressure trough and cold air pool that is delivering showers to parts of the region during today, that activity expected to increase during Friday as moisture deepens from the south and combines with the colder air. Some heavy falls are possible in the southeast. Another system approaches next week with a broad band of rainfall following some warmer weather across the region. The added warmth increasing the thermal dynamics and bringing about and higher chance of moderate rainfall with this feature. Another system looks to approach in the medium term as well.

00z GFS Precipitable Water Anomalies next 16 days

Modelling continues to support drier air over the nation being overrun through northeast part of the nation with trade winds and with another impulse over the southwest of the nation. This will start to erode the dominance of the drier air under high pressure and by next week as mentioned, we will have widespread moisture passing through from the easterly winds and then being pumped into the eastern and central inland of the nation. The trough over eastern inland QLD will bring showers and storms as the moisture is lifted through the region. A signal of the seasonal shift underway. A strong cold front and trough then runs into this moisture, that is still the case this evening. Through the medium term we will be watching the north of the nation where moisture increases and whether the Indian Ocean will decide to wake up and play a part in introducing rainfall through the north and west of the nation.

00z Euro Surface Pressure Pattern for the coming 10 days

The surface pattern pretty similar in the short term, the models only disagreeing on the timing of the troughs passing through the southeast inland tomorrow and how much moisture gets involved and drawn north and the trough and low how it evolves over the Bight and how much moisture gets involved in the system as it passes over the region. Over QLD, the model divergence continues through the early part of next week, Euro sees the storms over the northern parts of the state but the GFS has much more widespread precipitation. I will say that GFS has picked this week very well so will continue to side with this solution. Then next week the frontal system over WA that brings the widespread rainfall event from west to east, is anticipated to bring a very warm start to spring over the east and central areas of the nation, but for the west, much colder start to the month that usual. Over the north the tropics also becoming more humid with a northeast flow. The major system next week being forecast by Euro tonight is much slower than GFS and therefore the rainfall has been pushed back.

00z Euro Rainfall for the coming 10 days

The rainfall is less than the GFS for the upcoming 5 days with a drier airmass being depicted by the deterministic run of the Euro, but again the GFS has picked the placement of the elements better than the Euro of late. The Euro brings in a weak trough over QLD with scattered showers for the coast, more isolated inland with the chance of thunderstorms. Then all eyes focussed on the weather out west with the large scale wave of low pressure and frontal weather passing through from the west, which will headline rainfall chances for the nation next week, as it crashes into the moisture surging in from the easterly winds on top of the strong high. The erratic nature of Euro of late means it is a lower confidence forecast with many systems floating about in the coming week.

00z Euro Precipitable Water Values next 10 days

The Euro has shifted away from the GFS with less moisture gradually building back up with widespread rainfall and storms developing first in QLD thanks to the trough in the region combining with onshore winds before that weather turns south to spread the showers down the coastline but in less coverage but again this could change. A series of troughs out over the west tries to bring in modest moisture through the southern and eastern inland of the nation this weekend but the drier air looks to win out there. Next week, once a high has re-established itself over the east, a stronger longer fetch easterly wind will propel the moisture inland to the NT and SA and this is swept up by a strong front which you can see leads to widespread rainfall developing across the nation and the moisture may build up further over northern Australia as the northeast flow continues over the north.

Rainfall for the next 10 days

I have drawn in more rainfall than what you can see above in the next 10 days because the moisture running through the suite of models is deeper than pervious weeks and I suspect that the models will play catch up, in particular with the system next week into weekend, so it is some ways out. It could change back drier, but I am not leaning that way just yet. For now, the rainfall of note is over the southeast in the coming 24hrs and then again during the weekend with a weakening trough. Later next week, from as early as Friday, rain should start to develop over the region, the Euro pushes that back to Sunday now, I do not agree with that. So you will see on all your apps that there is no rain...the apps are computer based forecasting, not human based forecasting.

Climate Update tomorrow - for summer 2021!!! Due out at lunchtime!!!

74 views0 comments