A very active day for parts of the southeast, but if you are living on and east of the divide, it is cloudy and cool with an east northeaster and areas of drizzle. It feels very stable under the deck of low cloud. This will keep things calm today, but your turn comes tomorrow.
The main storm activity is just to the west of the low cloud today, this is where the surface based instability can increase as the day warms up. The instability is not especially high, however with the dynamics approaching SA and then moving east in the coming 12 hours, it should be enough to support thunderstorm activity this afternoon and overnight.
These storms will track eastwards in a weakening phase and reach the cool and stable southeast inland of NSW and the ACT later tonight.
Note the deck of low cloud over the eastern seaboard, that is the moisture left over from the first system that has become stuck in between systems. This may mitigate the severity in weather today, but will have to watch trends by this afternoon. The cloud is expected to break up a little more this afternoon. The main thunderstorm activity will occur between the cloud over the east and the approaching trough over the VIC/NSW/SA border region. This is where we should see fresh storms develop. Along the face of that trough, heavy rainfall and gusty winds may cause some problems, mainly through VIC. A very small chance of large hail does exist on the northern tip of the trough over southern NSW, but the cloud cover seems to be beating down that risk for now.
State of Play Wednesday
It is cool in the east with thick low cloud with drizzle and light showers about, that should start to break up this afternoon, but will limit any thunderstorm activity where that cloud lingers. Over the western inland of NSW through much of western and central VIC, showers and thunderstorms are expected to break out ahead of a trough that is moving slowly southeast through SA into the southeast inland. There is the chance of severe storms in this region as the air is holding more moisture and the atmosphere is likely more unstable as the temperatures rise. The storm initiation may take off after 4pm today and persist overnight and spread east. Some storms could be severe with damaging winds and heavy rainfall leading to flash flooding, mainly through VIC.
Simulated Radar 11pm
Note the band of storms pushing through VIC with the chance of heavy rainfall from Yarrawonga through to Bendigo and into the western suburbs of Melbourne through Warrnambool. Scattered showers for the east coast and a few low topped thunderstorms possible over Alpine areas this afternoon. Check out the low further west.
Simulated Radar 2am Thursday
Band of weakening storms moving through southern NSW and much of VIC with moderate to heavy falls, mainly through VIC. The rain pushing south through Melbourne. The weather over SA of great interest as that low wafts through the state there. That could help to kick off storms through Central NSW early tomorrow morning with damaging winds, heavy rainfall and a hail risk.
Simulated Radar - 5am Thursday
Showers and storms through the southeast of NSW and the ACT with some of those possibly severe with damaging winds, heavy rainfall and large hail. The risk is low due to the time of day the storms are forming, but with the lift increasing from the west, the dynamics aloft improving with better wind fields, storms could still pack a punch. Most of VIC may get into dry air behind the lead trough.
Thunderstorm Forecast Wednesday
This forecast runs to midnight and I will have updated charts for Thursday this afternoon.
The thunderstorm activity is expected to kick off along and ahead of a trough this afternoon and this evening with the chance of damaging winds and heavy rainfall mainly through VIC at this stage, but that risk could develop over Central and Southern inland NSW during early Thursday with an amplification of the trough as a low moves up over SA. A very small chance of coastal thunder in the northeast.
Flash Flood Risk Wednesday
Damaging Winds Risk Wednesday - Thunderstorm induced.
Large Hail Risk - Wednesday
I will have further updates this afternoon and if storms fire ensure you stay close to warnings.