The dramatic weather predictions in all things rainfall has remained in place from overnight for eastern SA, much of VIC, most of NSW, the ACT and QLD. As discussed while we were dealing with the first system over the central and eastern parts of the nation, the end of the month would be wet from the 21st of November and that is what has verified.
There are some indications that the models may be softening on their aggression for some areas relating to rainfall over the food bowl and they continue to wiggle north and south with the heavy falls, this will continue to evolve so stay up to date.
Some areas could see up to 100-200mm of rainfall in quick time through the next few days and lingering rainfall into the weekend and cool cloudy conditions will mean not much chance for things to dry out.
Potential for another low and rain event next week over the same areas is also cause for significant concern and we will take a look at that potential too as the GFS and Euro now in agreement on that event developing over SA and then moving into NSW, VIC and QLD.
For WA and SA, things are much more benign, eastern SA could see a rough day of weather Wednesday through Thursday before conditions settle, the next system expected to form further east of the state at this time.
The weather up north expected to be relatively seasonal though the coverage of thundery weather may move above normal with tropical waves passing west from the Coral Sea.
Lets take a look.
Rainfall Next 10 Days
Extensive rain is anticipated to form from later today through inland SA before increasing in scale and intensity from Wednesday with a low forming on a sharpening trough. The moisture content throughout the interior and the eastern inland should be well above normal and this trough will run into that moisture allowing for heavy areas of rain to develop with significant chances of flooding for many locations. The rain and thunderstorm activity will move east and north slowly by Friday and then into the weekend but the weather may not totally clear parts of NSW and QLD. The south will dry out with a strong southeasterly flow. The west sees no rainfall for at least the coming 7 days. Another system may redevelop through southeast and eastern Australia and that may tap into the moisture that hangs back over NSW and QLD creating another major rainfall event over the sodden east. The tropics looking on track for more stormy weather with seasonal weather
Thunderstorm Forecast Tuesday
Thunderstorms are expected to form along a trough over central areas of the nation today and progress east to be in western NSW and northwest VIC later in the day if not tonight. Some thunderstorms are expected to form in the east, with a handful of these possibly turning severe. Thunderstorms are likely to develop once again over the northern tropics and extend south through the NT into the trough passing into the eastern states. Some of these may be gusty.
Thunderstorm Forecast Wednesday
Thunderstorms becoming widespread over eastern SA through VIC and into NSW. Thunderstorms may turn severe with heavy rainfall and damaging winds the main concern. Thunderstorms over QLD will turn severe through the afternoon west of the divide with heavy rainfall leading to flash flooding the main concern.
Thunderstorm Forecast Thursday
Thunderstorms are expected to be widespread through the east and north with the risk of severe thunderstorms, producing heavy rainfall leading to dangerous flash flooding and damaging winds, mainly over NSW, the ACT and QLD. The tropics will see widespread showers and thunderstorms with some damaging winds and heavy rainfall.
Thunderstorm Forecast Friday
Thunderstorms beginning to shift north and east as a drier southeast to southerly change moves through the southeast states. Ahead of the wind shift, the deep moisture is still in place with a risk of flash flooding and riverine flooding with the heavy thunderstorms moving over the region. Storms over the tropics also severe about the western Top End with damaging winds and heavy rainfall. This could spread into the Kimberly as well.
Riverine Flood Risk NSW and VIC.
The below data sets support the risk of flooding from minor upwards with ongoing floods having renewed peaks as well. The band of heavy rainfall from SA through northern VIC and southern NSW may shift north and south over the coming days so this will determine exactly who gets the flooding in the coming days. This heads up forecast will become more refined hopefully by tonight or tomorrow morning as data becomes more settled.
Riverine Flood Risk QLD
The below data sets support the risk of flooding from minor upwards in all zones, the risk is highest the further south and east you are in the state. Similar to above, the placement of low pressure will determine the potential flood risks or renewed flood risks.
DATA - Refer to video for more details.
12z Euro - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days
I will just mention here again that the position of the low will determine who gets the heaviest of the rainfall but the risk is high for flooding for a broad area so stay up to date if you live in eastern SA, through much of northern VIC and into NSW and pockets of central and eastern QLD. Next week watching the second feature which could see another storm outbreak develop for central and eastern parts of the nation. And finally the west of the nation turns dry and bakes under ridging and easterly winds.
12z Euro - Precipitable Water Values - Next 10 Days
More information in the video about this chart. Watch the moisture rotate back around the top of a high and be placed over SA, VIC and western NSW this time next week setting up the next rain and storm event.
12z Euro - Rainfall Accumulation - Next 10 Days
Refer to video for more
12z CMC - Rainfall Accumulation - Next 10 Days
Refer to video for more
12z GFS - Rainfall Accumulation - Next 10 Days
Refer to video for more
Notice the split in the rain band over the east that is starting to appear, that could be a result of the low taking one batch of rain through the southeast and the trough moving northeast over QLD and northern NSW meaning some areas could be spared. Fingers crossed this develops further.
I will have more on the potential follow up storm and rain event next week plus your next 6 week weather forecast as we track more unstable weather from now until Christmas.