MEDIUM TERM FORECAST - THE RUN INTO CHRISTMAS REMAINING WET FOR THE EAST AND NORTH - HOT OUT WEST.

The typical December forecast across the nation as we track heat from northwest through to the southeast through the period from the 13-20th of December and likely to see that replaced with moisture streaming in from the north and east with the monsoon knocking on the door as we track into the week leading into Christmas.


But let us take a look at the mess that is the medium term, the data sets are appalling and there is little confidence about the evolution of the tropical weather, it's influence on the weather through the south and east of the nation.


There is a higher confidence on the heat building throughout the nation's northwest and this spreading south and east. The precipitation forecasts beyond this week is very low confidence so watch this space.


Lets take a look

FORECAST

Moisture Watch Next Week - December 13-20th 2021

Deepening moisture profile via the tropics will continue to dominate the rainfall spread for the nation, the amount of moisture that spreads from the north will dictate how much rainfall is viewed. There is another pulse of moisture in the Pacific and Coral Sea that appears to be holding a higher chance of elevated rainfall chances coming through during the region offshore but this could easily flip further west so must watch closely. The main impact will be another shot of moisture running from the northwest through to the southeast from WA through the central interior and the southeast of the nation.

Rainfall Next Week - December 13-20th 2021

Rainfall will be more concentrated from northwest to southeast with heavier falls over NSW, the ACT through to QLD and back up to the tropical north. Minimal rainfall likely for much of WA and SA at this stage, but this as mentioned above could easily change with the development of the tropical weather.

Rainfall Anomalies - December 6-20th 2021

Rainfall anomalies very elevated for above average rainfall over the coming fortnight for the ACT and the southeast of NSW where there is the risk of flooding developing this week. Additional rainfall in the period the 13-20th would be likely further north of this region into northern NSW and into QLD through to the tropics. The weather over the rest of the nation seasonal but there are elevated risks of a rain and storm band development from the northern WA into central Australia and into the southeast of the nation. That could be a productive band of weather, but where that sets up is still yet to be established. SA and southern WA mostly rainfall free.

Temperature Anomalies Next Week - December 13-20th 2021

There will be a band of high heat stretching from northwest through to southeast in advance of potential monsoonal weather over the north. The west as new high pressure ridges in should see cooler than average weather for a number of days during this period before the weather returns to warmer values. The east under persistent onshore winds should remain cooler than normal with the heat building on and west of the divide.

DATA


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

More details can be found in the video.

18z GFS Precipitable Water Anomalies - Next 16 Days

More details can be found the video.

18z GFS Rainfall Accumulation - Next 16 days

More information found in the video.

12z CMC Rainfall Accumulation - Next 15 days

More information found in the video.

12z Euro Rainfall Accumulation - Next 15 days

More to be found in the video.

The Control fairly similar - more details found in the video.

More in your state based forecasts this evening after 6pm EDT.