High impact thunderstorm activity is forecast to develop on Thursday afternoon through SE QLD and as far north as the Wide Bay, over the flood impact zones. This is in direct response to the passage of a westward moving low pressure system into the NSW coast, this creating a more dynamic atmosphere supporting robust convection.
The wind shear aloft is sufficient to set the updrafts into motion, meaning that significant thunderstorm activity is possible. Thunderstorms could produce all modes of severe weather in the SE and Wide Bay with the risk of giant hail and tornado activity.
For the remainder of the southern and western interior, extending into the central, staying dry for a few more days with ridging from Central Australia.
Along the remainder of the coast, we have onshore winds likely to produce showers, some heavy over the sub tropical and tropical QLD coast in the easterly winds.
The storm activity will continue on Friday and into the weekend over the SE and Wide Bay, before the spread of storms heads west again with a deepening inland trough next week. The persistent easterly winds also supporting above average rainfall chances through this period.
Lets take a look
Rainfall Next 10 Days
Rainfall is expected to be significant with the storm outbreak over the SE and Wide Bay during Thursday and possibly over the weekend with a secondary trough and upper low moving through the southeast of the nation. Deep moisture stuck over the southeast and central coastal areas will lead to locally heavy rainfall with additional flooding risks. The severe storms also capable of producing significant severe weather impacts. The weather over the north likely to remain at seasonal to below seasonal rainfall values, that in thanks to the weak trade winds and little instability as the monsoonal break continues. Next week, the trough over the coast will then head back west into the southern interior, with showers and thunderstorms increasing in coverage over inland areas and showers remaining heavy at times over parts of the southeast and central coast. So the wet phase continues. Far western and northwestern areas remaining mostly dry for now.
Thunderstorm Forecast Thursday
Thunderstorms are forecast to redevelop on Thursday with storms likely to turn severe very readily with a deep moisture profile, significant instability and wind shear combining to produce high impact severe weather. The thunderstorm activity may reach dangerous levels during the course of Thursday afternoon. All modes of severe weather is possible about the southeast, refer to charts below. For the the remainder, scattered showers and thunderstorms will continue for the tropics and sub tropics with moderate rainfall possible.
Flash Flood Risk Thursday
High precipitable water values will lead to a significant risk of flash flooding returning with thunderstorms during the afternoon and evening. Thunderstorms will likely form over saturated ground leading to significant risk of renewed peaks on some river systems..
Damaging Winds Risk Thursday
Damaging straight line winds are possible with thunderstorms during the afternoon and evening with destructive downbursts possible near supercells.
Large Hail Risk Thursday
A very high chance of large hail given the wind shear aloft supporting rotating updrafts, suspending the large hail for a long duration and these large thunderstorms producing strong downbursts, seeing the stones unable to melt on the journey down. Hail stones could exceed 5cm in some locations.
Tornado Risk Thursday
Severe thunderstorms may turn supercellular during the afternoon on Thursday, particularly on the Great Dividing Range, with a high chance of an isolated tornado or two forming in the region of deeper red.
Severe Weather Risk This Weekend
The severe weather risk returns from Friday through Victoria with a deep upper low moving in from the Bight. It will drift east northeast through the southeast inland of the nation driving showers and thunderstorms. These storms will be able to produce significant amounts of rainfall thanks to the very high PW values across the region. Damaging winds and large hail also possible with favourable wind shear available as well. There may be a renewed burst of heavy rainfall along the coast into next week with the trough tapping into easterly winds.
DATA - Refer to the video for further information for the daily breakdown and looking at the medium term
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks
Refer to the video for more where I will cut down the amount of reading tonight, however the major weather event on the east coast in the short term, Anika passing through northwest WA feeding a trough moving into the southeast which runs into residual moisture over the eastern inland, will lead to another severe weather event for NSW, VIC and QLD this weekend. And the chance of a little quieter weather? What are the chances?
00Z GFS - Precipitable Water Values - Next 2 Weeks
Another soupy 7 days for the east and north of the nation but the drier air is trying to push the wet air out of the region but it is having a tough time. While there appears to be quieter weather in the medium term, I do not buy it. Not with the positive SAM phase which could eclipse the phase we have just endured. So on that logic, wetter conditions into the medium term for the east and drier weather for the west seems like a logical outcome for the moment. The MJO is the wild card hustler at the moment, will it redevelop and increase moisture over the northern tropics?
00Z GFS - Rainfall Accumulation - Next 2 Weeks
Refer to video for further information
A closer look in - the GFS has been underplaying the rainfall in recent events so expect some more changes especially with the upper level systems in place! Also the trade winds might start to bring back heavier rainfall to FNQ in the medium term.
More coming up tomorrow from 8am EDT. I want to get this rainfall event in the east and TC Anika through the nation before revisiting the medium and longer term rainfall projections with heaps of contamination in the short term with these events so a better look tomorrow or Friday.
Please be safe with the severe weather potential tonight and tomorrow.