MEDIUM TERM FORECAST - THE SECOND SYSTEM NEXT WEEK FOR THE EAST AND THE TROPICS TURN WET.

The west also turning much warmer through this period too with a strong easterly flow developing across the nation into the medium term, bringing cooler weather and showers to the east, but these winds running over land will dry and bring warm to hot weather to the west.


Up north, keeping an eye on the tropical weather that is creeping further south, the more regular rainfall and active thunderstorm period is not too far away as we edge towards the wet season.


But the immediate concern is over the southeast and east with heavy rainfall this weekend but what about this secondary system next week? Should this be a system of concern?


Lets take a look

FORECAST

Moisture Watch This Week - November 18-25 2021

Well we can see the moisture lurching southeast from WA into SA and the eastern states, being lifted by troughs and low pressure, more rain, more below average temperatures likely this week for the same areas. The drier airmass may be left for the southwest of WA where high pressure will be and the tropics and the east remain soupy which is seasonal.

Moisture Watch Next Week - November 26-December 3 2021

Another shot of moisture out of Indonesia into the jet stream is likely to develop through this period and spark another rainfall event for the western interior and then move eastwards as we get into December. Another surge of moisture via easterly winds will pump itself into the interior and then turning southeast into VIC and NSW and much of QLD. The weather is expected to be quite wet through the north and east with deeper moisture levels remaining in place.

Rainfall This Week - November 18-25 2021

Rainfall becomes heavy through a narrow band from southern WA into SA then northern VIC and expands in coverage over southern and eastern NSW this weekend. The totals will be highly variable as we get better guidance on where the low pressure system travels. Low confidence remains on the forecast packages regarding rainfall. The remainder of the north and east is expected to be humid and more unsettled from this weekend as the moisture deepens as winds veer northeasterly. The west turning drier from the weekend with a warmer easterly flow developing.

Rainfall Next Week - November 26-December 3 2021

The prospect of moisture building via easterly winds remains the higher chance in the medium term and offers the northern and eastern parts of the nation more rainfall. The further west you go, the less rainfall you are likely to see however, the moisture seeping south and east out of Indonesia with a tropical low needs watching and of course the hype around a tropical wave on some of the modelling through northern QLD may also offer some heavier rainfall for northern and eastern QLD. The west remains drier with persistent ridging and easterly winds.

Rainfall Anomalies - November 18-December 3 2021

The rainfall anomalies remain above average over large chunks of the east and southeast. Under a cloud band that feeds a narrow band of rainfall that will be orientated northwest to southeast over southern SA through to the southeast of NSW. More widespread rainfall expected to develop over the tropics may be heavier than normal especially over the northeast tropics. Onshore winds developing once again brings the chance of elevated rainfall chances thanks to above average SSTs throughout eastern NSW and QLD. The moisture may feed troughs over the interior of these states bringing a better coverage of showers and thunderstorms. The west, dry but that is seasonal, however watch the weather off to the northwest over the Indian Ocean.

Temperature Anomalies This Week - November 18-25 2021

The temperatures generally seasonal throughout though leaning cooler than average under cloud cover and rainfall. Leaning warmer than normal along the west coast in easterly winds and the heat levels reducing under the weakening ridge.

Temperature Anomalies Next Week - November 26-December 3 2021

Stronger signals for warmer weather out west with a persistent easterly flow. That same easterly flow will provide more moisture and cloud cover with rainfall chances increasing throughout this period leading to marginally below average temperatures with higher humidity.

DATA - More details in the video above.


18Z GFS Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

18z GFS Precipitable Water Anomalies - Next 16 Days

18z GFS Rainfall Accumulation - Next 16 days


12z CMC Rainfall Accumulation - Next 15 days

12z Euro Rainfall Accumulation - Next 15 days

And a reminder that a modified update will be available this evening as I am attending a funeral this afternoon.