The persistence of the humidity and unsettled is here to stay, ending a wet Spring for many and starting the Summer season in wet fashion. The storms are expected to be strong to severe each day this week with heavy rainfall leading to flash flooding and perhaps some damaging winds coming up at times this week.
For those under the risk of storms this week, pay attention to the forecast risks surrounding flash flooding and how that impacts the riverine flooding. Many areas are teetering on the edge of significant flooding if the next rainfall event passes through.
For the tropics, the weather becoming wetter as the trades freshen up and run over the warmer than normal SSTs over the Coral Sea. The moisture will be propelled over the state from the tropics throughout this week with widespread rainfall chances throughout this period, but the far west may escape the heaviest of the rainfall.
The rainfall chances do persist into the medium term.
Lets take a look
Rainfall Next 10 Days
Rainfall will remain a daily fixture with the showers and thunderstorms more numerous during the afternoon and evening over the inland regions. The thunderstorms may become stronger during the latter part of the week with a stronger upper trough meeting the existing trough before the pattern starts to relax again back to what we are seeing today. There is evidence the rainfall chances may increase into the second week of the month with locally heavy rainfall developing over inland areas.
Thunderstorm Forecast Monday
Thunderstorms will redevelop during the afternoon and evening over inland areas, with the chance of these delivering heavy rainfall leading to flash flooding. There is a low risk of damaging winds and large hail but the flooding is the main concern at the moment.
Flash Flood Risk Monday
Flash flooding is a high risk through the central and southern interior of the state with rainfall rates of 50mm/hr possible, but these should remain fairly isolated. If you get a thunderstorms you will most certainly know about it.
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. Where it rains, it could be very heavy and flash flooding will be high impact in some locations!
More details coming up from 7am EDT.