MEDIUM TERM FORECAST - THE TAP IS ABOUT TO BE TURNED ON AGAIN!

Let's get straight into it - I have covered off some of the elements in play including the persisting low pressure and moisture content around Australia so lets see what the latest forecasts are moving into the end of the month.


Lets take a look

FORECAST

Moisture Watch This Week - November 15-22 2021

Moisture is coming back!! The drier air that is caked over the nation today and through to about mid week is expected to be overrun by the moisture via easterly winds over QLD and the NT and the northwest flow aloft through WA coming into the interior. The moisture from the northwest is expected to sweep into the southeast and southern states while moisture from QLD will be pulled into NSW ahead of troughs developing over the interior from later this week.

Moisture Watch Next Week - November 23-30 2021

Another surge of tropical moisture, perhaps with a decaying tropical low moving south through the Indian Ocean may crash onshore the northwest of WA and passing through to the southeast of the nation with elevated levels of moisture. Moisture through the Coral Sea via easterly waves, the deepening moisture levels will be moving over the tropical north but also being shearing southwards throughout QLD into NSW ahead of troughs passing over SA and VIC which could lead to this moisture being stuck over the region to round out the month and kick off December.

Rainfall This Week - November 15-22 2021

Rainfall turning heavy this week from SA into VIC and NSW with the placement yet to be determined for the heaviest of the rainfall but the potential is very high for further above average rainfall. The weather over the tropics dry for the first half of this week, but the rainfall returns later this week with deeper moisture and instability increasing, showers and thunderstorms to redevelop. The east coast may see a few showers and thunderstorms with a weak trough during Wednesday or Thursday before that risk returns this weekend. Another rain event emerges through southern WA into SA from this time next week and will create a wet and unsettled end to November for the east and southeast.

Rainfall Next Week - November 23-30 2021

As mentioned above, the rainfall event from SA moves into the eastern states with moderate to heavy falls possible, again placement of this event yet to be determined but all models show that event drifting east. Higher moisture levels over the north and east of the nation will creep southwards with an uptick in showers and thunderstorms most afternoon over interior parts. A deep tropical low may make an approach to the WA coast or remain offshore, with rainfall chances potentially coming up.

Moisture Impacts This Week - November 15-22 2021

The reduction in atmospheric moisture has been reflected in the clean out of cloud cover for inland areas and a chance to dry out. The lack of moisture is combining with the cooler air arriving from the south to continue the below average temperatures. The weather over the west is turning more humid as we get into mid week and that moisture will deepen on approach to SA and the eastern states later this week into the weekend with rainfall chances coming up. In the east, moisture profile increases as winds veer into the east mid week and over the tropics, enjoy the drier air, the weather is turning very humid this weekend and will likely stay that way until April.

Moisture Impacts Next Week - November 23-30 2021

The moisture levels turn very high over northern and eastern parts of the nation with that creeping southwards into the central parts of the nation with rainfall chances increasing. Thankfully temperatures are not as high, so the elevated risk of disease is not quite there this week with the rainfall and moisture profile.

Rainfall Anomalies - November 15-30 2021

Above average rainfall chances set to continue for large parts of the nation during this period, this is thanks to a resurgence of moisture via the warmer than normal SSTs around Australia and the climate drivers continuing to aid above average rainfall. The SAM remaining positive, the waning negative IOD influencing moisture from the northwest into inland lows over WA and the onshore winds producing showers along the east coast will pump moisture into inland troughs over the east. The tropics will see a surge in convection during the latter part of this week into next week.

Wildcard Systems - November 22-30 2021

Watching the tropical system over the northwest of WA, will it crash onshore? Models have also been playing with the idea of deepening low pressure over the eastern inland of QLD into NSW and pulling up stumps and becoming slow moving. This event if it does verify would lead to major flooding. But it is a wild card system and something to watch.

Temperature Anomalies This Week - November 15-22 2021

Temperatures are well below average to start the week, after a very cold weekend, but the numbers are expected to come up back to seasonal nation wide by around Wednesday and stay in the average zone for much of the outlook under rainy cloudy skies. An absence of colder air through the outlook period meaning the air will be gradually becoming more humid and soupy across northern and eastern Australia. The tropics hot and dry to start the week will see a reduction in temperatures but heat levels come up as humidity increases.

Temperature Anomalies Next Week - November 23-30 2021

Temperatures near seasonal for most of the north and east and perhaps some warmer days ahead for parts of SA and WA. But that may be tempered by more cloud and rainfall still floating through into the southeast and east. The below average temperatures may return for the eastern inland with more cloud and rainfall developing with higher humidity values. A similar arrangement to what we saw last week.

DATA - Refer to video for more analysis


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

18z GFS Precipitable Water Anomalies - Next 16 Days

18z GFS Precipitable Water Values - Next 16 Days


18z GFS Rainfall Accumulation - Next 16 days

More details in your state based forecasts this evening and a look at the rainfall data sets after 9pm tonight.