MODELS AND RAINFALL - NUMBERS CONTINUE TO COME UP FOR MANY AREAS EXPOSED TO THE WESTERLY WIND REGIME

No surprise to the guidance from the modelling as we see the westerly winds starting to become more aggressive and this is in relation to the SAM being more neutral resulting in the frontal weather being more seasonal, and at this time of year, the frontal weather does feature quite regularly for Southern Australia.


The added complexity to the pattern become more wavier is that it is drawing upon more moisture and with the thermal gradient also becoming more acute across the nation, the rainfall numbers increase.


However, the spread of rainfall with each individual system should be taken on merit and refer to the daily weather videos for more on that.


The trends in the medium term continue to offer welcome falls for areas that need it and for now, the east coast looks to be spared the heaviest of the falls, while not completely dry, it is welcome to see the westerly wind bias returning for a period.


ENSEMBLE DATA

GFS - Rainfall Following 7 Days (median of 35 members) - MODERATE CHANCE

The weather getting wetter for the southeast with the frontal weather gathering pace and collecting moisture and then settling a fairly wet outlook for the first week of August which may spill into the second week of the month. Rainfall also spreading throughout the interior with the moisture linked to the Indian Ocean Dipole. This will continue to feature more prominently over the weeks ahead as we see an increase in the westerly wind regime impacting southern Australia, drawing the moisture southwards into the fast flow pattern.

CMC - Rainfall Following 7 Days (median of 30 members) - LOW CHANCE

Not much change from last night with the east interestingly enough carrying higher rainfall chances with a cloud band settling over QLD and NSW. Moisture increasing throughout the interior from the Indian Ocean does bring up the chance of above average rainfall chances. The rest of the south expecting more frontal weather but the CMC struggles in these situations.

EURO - Rainfall Following 7 Days (median of 51 members) - MODERATE CHANCE

The rainfall spread is somewhat unchanged from this morning and there are multiple systems on the board for the short and medium term. While the GFS is rather activated with high rainfall numbers coming throughout the next two weeks, the CMC shows less and the Euro sits in between. That is why my forecast is similar to the Euro’s at the moment as in these situations, often the truth is in between the extremes most of the time.


LONG TERM

CFS - Rainfall Next 6 Weeks - MODERATE CHANCE

The longer-range trends keep the heavier rainfall going throughout the interior and spreads it from west to east throughout the country, and depending on frontal weather placement and low-pressure placement, this will determine who gets the heaviest and most frequent rainfall rates.

MEDIUM TERM

July 31st - August 15th, 2022

Moisture Watch

The moisture is largely unchanged throughout the medium term as we track the larger weather events over WA and this then filtering moisture throughout the country from northwest to southeast ahead of cold fronts. There will also be moisture spreading through the Coral Sea and into northern Australia via the easterly wind regime! That moisture over northern areas of the nation needs to be watched as we will see that turning back towards the country via being drawn south and southeast in upper northwest winds leading to rainfall chances coming up for QLD and the NT.

That moisture over northern Australia will spread south and southeast into the NT and QLD with the dry season weather starting to shift as we have moisture coming up. Further heavy moisture continuing over southern Australia, the weather here likely leading to higher rainfall than normal over eastern and southeast Australia. Another wave of frontal weather may drag in moisture from the Central Indian Ocean into the SWLD.

Temperature Anomalies

Temperatures are forecast to remain well above normal for many areas this weekend and into next week as a long fetch northwest to westerly flow distributes the warmth throughout much of inland Australia. Another wave of frontal weather moving into SWLD of WA leading to cooler than normal weather, actually quite cold over the coastal areas under persistent westerly winds. Seasonal weather over the east coastal areas of the nation. Humidity values may start to rise over northern Australia.

The heat values remain higher than normal over the north of the nation with elevated SSTs coming into play and with moisture spreading throughout the north of the nation, this could lead to a marked increase in humidity values ending the dry season for a period. That warmth may begin to clash with the colder and drier weather surging northwards over south of the country behind strong cold fronts and low pressure. So more dynamic weather is possible with severe weather chances also coming up as the red and blue shading begins to get closer!

Rainfall Anomalies

The moisture values remaining very high throughout the interior will eventually lead to cloud increasing initially, with rainfall likely to increase in coverage over the nation's central and eastern areas. The rainfall over the southeast areas on and west of the divide could be well above normal with low pressure stacking up in the westerly wind regime and topography enhancing rainfall. Further strong cold fronts and low pressure peaking over the SWLD leading to more widespread falls and with the SSTs continuing to run above normal offshore the west and southwest of the Ag Areas here, the rainfall could continue at above average values (as seen over the weekend 75mm observed in some areas).

Rainfall over the central and eastern inland of the nation is tending above average with a northern movement of the westerly wind belt flicking some low-pressure systems through southern parts of WA through SA and VIC and that may continue through this period, however given we are likely to have moisture running over the NT and into QLD, this could be lifted into widespread rainfall with low pressure forecast to be over QLD, NSW and VIC. Further moisture may activate into cloud bands offshore WA and this coming through with the next wave of rain and thunderstorms moving in towards mid month.

More coming up from 5am EST with a look at the elements in play, this ahead of the next weather video from 8am EST.