MEDIUM TERM FORECAST - FOCUS ON THE RAIN EVENT THIS WEEKEND AND THE FOLLOW UP TO COME.

There is a lot of interest on the forecast charts regarding the inland rainfall for the NT and SA, then points east across the weekend. The divergence in modelling makes it very tricky to forecast exactly who gets what over the coming 5 to 7 days which is frustrating for those not wanting rain in the east, those wanting rain in the south. A lot riding on it for many communities.


For the west of the nation, the lower than average temperatures are expected to continue for a while longer, a cool Spring so far, well modelled and forecast and this trend continues.


Up north we have been banging on about the early build up and early onset rainfall, and that has been underway for the past 4 weeks and this is expected to increase in the coming fortnight.


And we have further severe thunderstorm outbreaks expected in the coming fortnight over the east.


Lets take a look.

Moisture Watch This Week

A few models want to bring in moisture from the northwest of WA later in the period, but with the upper high in place through the region, little impact from that moisture is likely over WA, but more likely to see that moisture used over the central and eastern areas of the nation. The main moisture port this week comes via the Coral Sea and through the northern tropics and is pulled south and southeast into a eastern moving trough, and widespread rain and cloud should develop as a result. Drier weather back over the southwest.

Moisture Watch Next Week

No change from yesterday with moisture still recycling through the interior, some moisture may be coming through inland WA but the upper heights preventing any impact in terms of cloud and rainfall, and won't be until it hits the central and eastern areas of the nation that we see the impacts appear in the form of showers and storms. Moisture continues to stream out of the east and northeast via the trade winds.

Rainfall This Week

A lot of this rainfall expected from the weekend through next week with a deep pressure trough moving eastwards slowly through the nation. Some chance of this moisture heading further south if a cold front can absorb it. It is a low confidence forecast in terms of rainfall for the east and southeast of the nation, probably a better confidence rating now for central parts of the nation but your number will vary under thunderstorms. The west turns drier, though showery air may develop behind a cold front early next week for the SWLD. Heavy showers and windy weather for TAS this week in an onshore flow.

Rainfall Next Week

Rainfall confidence still remains low into the medium term as we track through to mid month. The ensemble data keeps the rainfall going over much of the eastern inland and through the southeast. The tropics come alive further with a better coverage of showers and storms and the west will see another cold front. Outback areas over the west could stay rain free for now.

Rainfall Anomalies Next 2 weeks

Rainfall anomalies unchanged from yesterday, the bias over the eastern and northern inland of the nation is set to continue as per climate guidance and the current synoptic scale.

Temperature Anomalies This Week

Cooler signal continues across the nation this week, two fronts over the nation allowing for below average temperatures for SWLD of WA. Extensive cloud developing over central and eastern inland areas of the nation will lead to marginally below average temperatures. Over the north, the above average temperatures continues.

Temperature Anomalies Next Week

The warmer signal grows a little for the eastern and northern parts of the nation into mid month. The southwest of the nation will see a colder signal continue with further onshore winds and frontal weather clipping the southwest of the nation. Ridging also leading to onshore winds. The areas in white over the south and east carry seasonal values, but there have been signals for a burst of very warm weather developing in about 10 days time for the southeast and east.

DATA - Refer to the video for further analysis.


18Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

18Z GFS - Precipitable Water Anomalies - Next 2 Weeks

18Z GFS - Rainfall Accumulation - Next 2 Weeks

18Z GFS - Temperature Anomalies - Next 2 Weeks

I will have the severe weather and wet season outlook and the impacts around the nation coming up very soon. This is imperative as I know there is an OBSESSION with rainfall, but weather is more than rainfall and the impacts of other elements can be as equally destructive and disruptive.



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