The significant rainfall signal continues into the medium term as the persistent easterly flow, upper level troughs and deep moisture combines to bring not only below average temperatures but more record rainfall chances to finish November and to kick off December.

A concerning development has been the strengthening signal of a persistent easterly flow feeding inland troughs that become slow moving near stationary, driving rain and thunderstorms over the same locations on a daily basis. This is forecast in addition to what is forecast in the coming 7 days.

Out west, stark contrast. That persistent ridge to the south of the nation will see a strong and dry easterly flow develop, sending temperatures into the mid 30s and sunny skies. The moisture rung out over the continent in a stable airmass.

The tropics remaining seasonal, though the early TC Paddy is likely to washout in coming days, but a sign of what is coming potentially this wet season.

Lets take a look - Trying to keep the video length down as you are all pressed for time at the moment.


Moisture Watch Next Week - 30th November - December 7th 2021

The moisture as alluded to yesterday is likely to hang back over northern NSW and QLD from this week and weekend and be propelled west back into eastern SA, through much of NSW and VIC. Humid and unstable weather will result and if the air does indeed turn warmer, then the humidity values will likely increase above where they will be this week, which is of great concern. For the west, the long fetch easterly winds, dry out so no real impact expected through the region for some time. The tropics obviously moist and unstable but some indication that moisture will seep further southwards through this period, adding to the moisture profile over eastern and southeast parts of the nation while lifting the central interior moisture profile.

Rainfall Next Week - 30th November - December 7th 2021

Significant risk of additional thunderstorms and rainfall activity for much of QLD, NSW and VIC. This weather creeping into the eastern and northern districts of SA back up to the NT and the tropical north. Some of the rainfall again, heavy at times with a flood risk continuing for the east and northeast of the nation. The rainfall may persist beyond this period for the same areas as the easterly winds continue. For the west, the weather is expected to be mainly dry though keep an eye on moisture levels creeping in from the north with the heat troughs dragging in northeast air from the NT and northern parts of WA.

Rainfall Anomalies - 23rd November - December 7th 2021

Excessive rainfall anomalies continue for the east, there is high confidence in above average rainfall but low confidence in exactly who gets the worst of it. As I keep mentioning through this period, some locations may record 100mm while down the road gets 30mm. So once again it does not have to rain heavily over your head to be impacted by flash or riverine flooding so stay up to date.

Temperature Anomalies Next Week - 30th November - December 7th 2021

Cooler bias continues for the east and central parts of the nation, though some evidence in a few of the global models that the warmth from WA may return through parts of southern SA and into VIC if the high can move east quicker next week and set up a northeast flow, so that may offset the cooler bias in these regions. Otherwise cooler than normal over the east. The northern tropics reducing slowly in those heat levels though they are hanging on.

DATA - Refer to video for more details.

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

18z GFS Precipitable Water Anomalies - Next 16 Days

The moisture is unable to move out of NSW and QLD through the coming 2 weeks which is cause for concern. Note the impact is scattered showers and thunderstorms is almost daily for NSW and QLD.

18z GFS Rainfall Accumulation - Next 16 days

Excessive rainfall and flood risks remain in place for the east and northeast. This is clearly the weather of most concern.

A closer look for those communities under severe weather threats through the coming 2 weeks. Your number will continue to chop and change.

12z CMC Rainfall Accumulation - Next 15 days

12z Euro Rainfall Accumulation - Next 15 days

I am very concerned about the severe weather risks for the eastern states. The flood risk is very high and I cannot emphasise that this is data, not a curated forecast. So some areas even in red zones could see double what is advertised above, some areas could see less and be spared but the impact is the same, water everywhere, high humidity and concerning flood risks.

Here is the latest 6 week outlook from the Euro this morning to add to my level of concern as we move into Christmas. It is quite possible we will be dealing with major flood issues for many inland communities.

I will have more during the afternoon with the state based forecasts.

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