MOISTURE WATCH FOR MID MONTH

Another update on the medium term, there is a lot of interest in the modelling and the moisture that is building up, but there is no skill in specifically forecasting impacts at this time, it is not possible.


However I can give you the data sets and break down trends for you.


Moisture to watch in the short term.


Moisture Watch - Week 1 - Model variation and direction of moisture this week.

A plume of moisture expected from the Indian Ocean is likely to link up with a cold front to bring a burst of showers and storms during Saturday before that spreads east on Sunday. Another strong front will bring yet another band of rainfall during Monday but this likely favouring the SWLD.

Over the FNQ coast, moisture is likely to increase as a northeast to easterly flow freshens. Showers increasing from early in the week could be heavy at times about the Cairns to Cardwell region. The moisture not quite penetrating far inland this week, with upper level winds shearing the moisture back into the Coral Sea.

A cold front that moves through WA during Monday will race through the Bight and bring a burst of showers to coastal areas of SA with a weakening cloud band. Moisture feeding into the southeast inland in northeast to easterly winds early next week will move west of the divide before it is captured by frontal weather to produce widespread showers and storms mid week over southern and central NSW at this stage with moderate falls.

Drier weather elsewhere for now.

Areas in yellow to experience the most out of the moisture this week.

Moisture Watch - Week 2

This is where the modelling is very divergent. There are mixed signals and this is just a guide to the data sets below this. At this stage there are areas to watch, the areas will move around from day to day, but there will likely emerge and event of interest during this time as we go through next week. So the confidence will increase as we get closer to this period. I will point out that GFS has trended drier again and CMC has wound back the moisture depth across the nation, but still has widespread moderate rainfall through this period. The Euro has widespread moisture building up with a bias of more rainfall over the eastern parts of the nation.

The DATA SETS


Euro 12z Ensemble Data sets - Next 15 days

Note the moisture overruns the drier air through the interior during the coming week and then we see a bias towards elevated PW values over much of the nation through mid month into the end of August. The bias with the Euro places the highest rainfall potential over central and eastern areas of the nation. There is no clear guide on where and exactly when a low pressure system lifts this moisture into areas of rainfall. That will become clearer in the coming week.

Euro 12z Simulated cloud cover - Next 10 days

Note the cloud band developing over the west also carrying itself eastwards through SA and into VIC, but with the lower levels drying out meaning we will see less rainfall here. But as that front moves further east, it will encounter deeper moisture over NSW and eastern VIC bringing up rainfall chances. The second feature that comes in from WA into SA later in the run is quite low confidence and I suspect that may change again.

GFS 12z Deterministic Data sets - Next 15 days

I will point out the moisture surging through the west is of high confidence and the moisture through the southeast and eastern inland ahead of a cold front passing through WA into the southeast mid week may also produce a short but heavy burst of thundery rainfall to eastern VIC and NSW. Otherwise the showery weather also carries a high confidence over the northern parts of the QLD coast. Otherwise from the medium term, the modelling is quite low confidence. I have posted the two most recent runs below so you can see them side by side. Not the divergence in the modelling in the medium term.

It is important to note the weather will continue to evolve during the next few days for the medium term. There have been all sort of solutions on the board and each of them have been rather dynamic and broad scale. I will update again during Saturday.

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