SA - DRY THROUGH TO ABOUT SUNDAY WHEN RAIN DEVELOPS OVER NORTHERN AREAS AND SPREADS SOUTHWARDS.

The positive SAM phase is helping to promote the movement of the wind fields into the east in the coming days, leading to a drier and warmer few days with clear skies and lovely Autumnal weather.


But at the same time the positive SAM phase is forecast to assist in projecting moisture through to central areas of Australia via upper level northeast to easterly winds via eastern and northeastern parts of QLD and into NSW. This moisture is likely to feed a developing trough later on Saturday.


Now as we move through the weekend, the airmass is forecast to become warmer and more humid as the airstream begins to shift into the northeast and starts to drag in some moisture from the tropics. A trough is still likely to form over inland areas of the nation between the Gulf Of Carpentaria and extend southwards into the north.


So from about later Sunday, that activity should begin to move southwards and eastwards with a decent chance of rain and thunderstorms being present across the state. The heaviest of the rainfall from this event looks to be on and west of the divide.


A long wave trough passing into the Bight could bring the next band of more organised rainfall but act to knock out the upper level disturbances and this leading to more typical weather for this time of year with the temperatures easing and more rainfall opportunities are forecast as well as we move into early May.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall is forecast to be lean over the coming 4 days with not much in the way of rainfall expected around the state under this firm ridge and stable dry airmass. But during the weekend the airmass will begin to shift and this is in line with the development of a trough starting to pull moisture in from the east. Cloud developing through the weekend, mostly over northern areas on Saturday and the remainder of the state bar the far west from Sunday will lead to scattered showers and storms. The trough then begins to adopt a southeast to easterly track next week as a zonal flow emerges from the west. So the risk of rainfall remains elevated over the coming week but the totals will shift around from run to run and expect changes to your numbers as the guidance gets better. More follow up rainfall is expected during the first part of May as well.

MEDIUM TERM - April 27th - May 4th 2022

Rainfall Anomalies

Moisture over the southern parts of the nation will drive more rainfall with heavier falls for those areas exposed to the westerly flow. Given the elevated SSTs around Australia, this will play out with above average rainfall chances once again, as seen with the last system, many areas scored higher in rainfall totals than modelling suggested and this logic must be applied while we have the elevated SSTs in place. Northern and eastern areas will see near seasonal conditions with a few pockets getting lucky in the far northeast for further beneficial late season falls.

Moisture Spread

Moisture should be on by the east with the main rain event off the board. The next wave of unstable weather south of the nation will bring a band of cloud and rainfall to southern and southwest Australia. Onshore winds over the east will bring showers and cloud and lingering late season moisture will be found over northern areas of the nation with more late season falls.

Temperature Anomalies

The temperatures have now reverted back to warmer across the nation as the next rain event is now contained into the shorter term forecast. There looks to be a colder bias still for areas over southwest Australia with frontal weather and about the northeast of QLD with onshore winds. Warmer and more humid air over the Top End and parts of the Kimberly. The upper northwest winds will bring that warmer air into the southeast states.

DATA - Refer to the video for further information and it is critical to keep check of the data sets to understand where the next major weather events are emerging from outside of this period. It may be quiet now but I am all about preparation and ensuring that information is shared with you as soon as it is available.


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

The pattern looks very much what you would expect through a period of transition. Please refer to the video for more information about the significant rainfall potential for Ag Areas over the coming 2 weeks and to put into context what you will be seeing across the data sets tonight.

00Z GFS - Precipitable Water Anomalies- Next 2 Weeks

The weather is certainly drying out over the course of the next 3-4 days with the most humid air reserved for the northeast tropics and across the east coast in onshore winds. The moisture is still forecast to move south and west through the east of the nation before we see a large moisture plume come ashore through WA and this races west ahead of a developing cold front over the southwest of the nation. This will merge with the moisture over the east to keep the rainfall chances going. This period looks to be quite volatile so expect to see more changes across southern and eastern Australia.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - once again your numbers will chop and change so be aware of that but multiple rainfall events are quite possible in the next two weeks.

I am under the weather covering the weather and I will have the next update from 8am EDT, pending the voice it may just be a written update but more to come! A very busy weather period on the way.

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