NSW - SHOWERS AND THUNDERSTORMS TO INCREASE THIS WEEK

The remains of the large scale low pressure system now sits over the eastern parts of the nation as a trough, triggering showers and thunderstorms most days this week. The rainfall is scattered and uneven, not the widespread rainfall we saw last week, but where it falls, it could be heavy!


Flash flooding also remains a risk most days with thunderstorms.


The main thunderstorm focus may be seen from Wednesday onwards as the trough in northern NSW heads south and then deepens as it passes to the east once again Thursday and Friday. Severe weather risks continue for the remainder of the week.


The trough will lift north during the next weekend and clearance of the humidity will be experienced once again.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall is expected to remain uneven and scattered through the coming days mainly over the GDR and points east to the coast, the better coverage through northern areas of the state, with a surface and upper trough wafting around with showers for the coast. The trough over the inland takes a journey southwards mid week with showers increasing statewide with the trough sharpening ahead of a weak trough in VIC Thursday. This all comes together and with the better wind profiles aloft and the deeper moisture levels, the showers and thunderstorms will become widespread later this week before clearing north during next weekend. The storm focus will remain over the northeast next weekend with the showery weather then extending down the coast into the following week. That will be a feature to watch as well with the positive SAM expected to drive rainfall chances for the best part of the next 2 weeks.

Thunderstorm Forecast Monday

Thunderstorms are expected to return through the northern inland of the state during the afternoon and evening. Thunderstorms may be strong to severe in pockets with heavy rainfall leading to flash flooding the main concern along with damaging winds.

Flash Flood Risk Monday

With saturated catchments and ongoing riverine flooding, the flood risk remains very high with heavy storms over the region.

DATA

00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

The pressure pattern is much more stable for a lot of the country as mentioned through the weekend, though the east cannot get a break from the wet and humid weather with daily storms expected near multiple troughs moving through NSW and QLD. The west is hot and dry with a easterly flow continuing. SA also under the ridge looking quiet for the coming week to ten days. The heat is on for parts of SA and VIC this week with above average temperatures for the last week of Spring. The warmest weather since last Summer expected. The storms in the east may thin out a bit later on during the week if not into the weekend as the troughs weaken and the ridge takes over. The tropics also looking active and will spread moisture south and west through the nation as the pattern shifts a bit. The medium term offering the tropical mischief which is normal, ignore the cyclone at the end of the run, it will be somewhere else next run. That is the model signalling the monsoon is heading south.

00Z GFS - Precipitable Water Anomalies - Next 16 Days

The PW values are still very elevated for large parts of the east and near seasonal over the north of the nation where rainfall is forecast most days. Where the air is drier than normal is over SA and WA for much of this week. The humidity however will be returning into the medium term and I am advising to watch from Dec 6th onwards for the pattern to turn increasingly humid and unsettled for many areas. The summer heat is not going to be dry over in the east season, and you will feel what I am talking about mid week.

00Z GFS - Rainfall Accumulation - Next 16 Days

More information in the video

A closer look in - note the uneven distribution of rainfall along and east of the trough this week. Rainfall for the southeast and east coast comes into the medium term.

More details coming up from 7am EDT.




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