Spring time continues to unfold across the nation, though we are now starting to move away from the colder side of spring and towards the warmer phase of the season. This usually takes place between mid September and mid October and it is normal to see the contrasting weather and the volatility in the modelling as we are experiencing right now.

With that said, more wild swings in temperatures for those living through southern parts of the nation will begin to settle down from mid month onwards, the rainfall frequency over the north will increase with the afternoon showers and thunderstorms, the rainfall frequency decrease over the southwest of the nation with the cold fronts moving away and the intensity of rainfall events increasing in line with rise in temperatures and humidity values.

All of this is starting to occur before our eyes. More on this during mid morning but lets look at the short term 7-10 days first and see what the rain event is doing in the east and how cold we are getting in the southwest.

Rainfall Next 10 Days

Rainfall is expected to be quite significant in scope throughout the weekend into next week, though who gets what, as been explained this week over Central and Eastern parts of the nation, remains up in the air until about tomorrow, once the system initiates in real time. For southeast areas of the nation, another low pressure system is being forecast mid to late next week on some of the guidance, but this again is dependent on how the weekend system evolves. Now for the remainder of the nation away from the eastern rainfall event, the confidence in rainfall is a lot higher, we will see showers return to the SWLD during early next week with a front and over the tropics, the random and scattered nature of the showers and thunderstorms will continue throughout the forecast period.

Thunderstorm Forecast Thursday

Thunderstorms are possible over parts of the outback with the weak upper trough passing east through the day. They will be mostly elevated and gusty at times, but non severe.


Euro 12z - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

The pressure pattern has turned a little more mobile for the weekend and will likely now see the interior trough and low become absorbed into the front and move more efficiently through the nation. Ahead and with the trough a band of showers and storms with areas of rain through the weekend into next week is likely. Patchy light rainfall for southern parts of SA, VIC and NSW. Moderate falls now likely over the central and northern parts of NSW and into southern QLD. Moderate falls scattered through parts of northern SA and into the southern and central NT. That is the current guide and will adjust again. Over the SWLD, the weather is expected to turn milder and dry through the weekend, but a strong cold front Monday will bring the next batch of showers and quite a cold airmass into the southwest and west of the nation for much of next week. That front spreads east and a deep low forms on the front by this time next week bringing up the chance of showers and storms for the eastern states. Over the north, once we lose the upper high, your coverage of showers and storms increases next week.

Euro 12z - Precipitable Water Anomalies - Next 10 Days

I have outlined more on this in the video but the Euro is in line with other models in spreading the moisture through the nations east but flicking it offshore NSW with the front and trough slowly moving northeast. Another pulse of moisture comes in from the northwest into WA but it is more shallow, that may provide more cloud than rainfall. That moisture will land in the southeast and may merge with left over dregs from the first low pressure system and help create the next rainfall opportunities.

Euro 12z - Rainfall Accumulation - Next 10 days

Rainfall has shifted further north since last night with the first system, then the secondary system comes through the southeast. These systems carry low confidence. For the north and the west, the rainfall confidence is grading to moderate, we lose the upper high over the north which will aid the thunderstorm development and over the southwest of WA, the front passing through next week will bring a burst of showers Monday before dry weather resumes. Showers up through northern QLD will also increase later in the period.

GFS 12z - Rainfall Accumulation - Next 10 days

Similar idea to Euro with two systems now passing through the east and southeast over this week. The moisture pools over the north of the nation in line with the seasonal shift and over the SWLD we will see showery weather early next week with colder weather to follow drying out the western interior.

CMC 12z - Rainfall Accumulation - Next 10 days

Also similar spread on the CMC where we have two systems on the board, the northward projection of that rainfall and moisture through the NT into QLD. A strong front through the SWLD of WA then moves into the east and creates a second low mid next week with rainfall for the southern and southeast states and follow up storms for northern NSW and QLD. Note the moisture creep through the west of the nation.

GFS 12Z - Temperature Anomalies Next 2 Weeks

Temperatures over the coming 2 weeks will be colder than normal for large parts of the nation with extensive cloud cover and inland rainfall over the nation. The SWLD should see a cool week next week and the medium term could be cold over the southeast and east on current guide but I think that carries a very low confidence.

I will have a look at the La Nina chances coming up later this morning and more on the medium term forecast for the nation, there is a lot going on as you can all see, it is changing from run to run.

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