NSW - THE FINE WEATHER CONTINUES - EVIDENCE OF RAINFALL NEXT WEEK.

I love spring, but forecasting the weather at this time of year is very tricky. The short term forecast is fairly benign, but beyond Sunday, things turn divergent in the guidance, being able to pin down an accurate forecast near impossible, so will tackle this forecast in two ways, with the shorter term and then what happens beyond Sunday for the state.


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ANALYSIS

FORECAST

Frost Forecast Wednesday Morning

Frost once again a high to very high chance about the GDR and adjacent slopes with the risk trailing off to the western border with SA. Severe frost possible about SE NSW and the ACT once again.

Rainfall for the next 10 days

The rainfall this morning as I showed you between the models was a good example showing that divergence next week. For the most part, the next 4-5 days should be dry, a front charging through VIC and TAS may spread a few showers over the southern inland however for the most part, the state will be dry. Next week, will we have a high pressure coming back in to clear out the region or do we have an upper low form triggering widespread rainfall over the eastern 2/3rds of the state? That question may remain unanswered for a number of days. For now I have drawn in showers over the east coast but not the heavy falls as I am not convinced at this time for this event to full unfold over the east, it could easily form further offshore or as the GFS suggests pass through as an open wave.

Rainfall Anomalies Next 2 weeks

Temperature Anomalies This Week - September 7-14 2021

Temperature Anomalies Following Week - September 15-22 2021

DATA


00Z GFS Surface Pressure Pattern for the coming 10 days

You can compare with the GFS to see they are in full agreement until the weekend with the weather diverging on modelling, especially in the east. The GFS passes through the cold front with a blast of showery wintry weather for the southeast as an open wave with no low pressure, allowing the weather to be more mobile throughout the outlook period. Not much rainfall expected for inland areas under this guidance. It does have good rainfall in the short term for the SWLD of WA with a front passing over during Thursday but sliding off to the southeast with no impact for SA and the southeast states until a follow up front arrives during the weekend, that is the system with very poor guidance across all modelling at the moment.

00Z Euro Surface Pressure Pattern for the coming 10 days

Comparing to the GFS the weather is well modelled until Friday and Saturday with the system rotating through the southeast with a decent cold outbreak with showery weather for the southeast while the west turns back to dry. Then the system is expected to develop into a low pressure system, this time more offshore the coast, hence less rainfall for inland areas of the east, as expected. The volatility in the modelling will continue. For the remainder of the nation, rather settled under a continuous belt of high pressure and dry air. The weather over the north will turn humid with showers returning to the northern NT and QLD.

00z Euro Rainfall for the coming 10 days

Not much for areas away from the coastline with the cold fronts passing over the southeast perhaps bringing the most widespread rainfall. Some of the showery weather may turn wintry on Saturday and Sunday. Then the system is expected to turn into a low pressure system next week with areas of rain and frequent showers along the east coast with moderate to heavy falls possible. The remainder of the southeast inland turns dry and cooler with high pressure at this time. But the modelling will change again overnight with that system next week very hard to pin down.

00z Euro Precipitable Water Anomalies next 10 days

The battle between the drier air and the moisture over the north and east will continue for the coming 10 days, though it will be just outside of this window that the moisture deepens across the nation with a more favourable pressure pattern developing with high pressure pushing further south.

I will have another look at the modelling and rainfall opportunities from all agencies after 9pm.



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