Lets get straight into it.
Before you look at these charts below, the darker green does not mean major flooding, it means the risk of flooding developing...
BUT I WILL STATE THIS - IF the upper end solutions below do verify for the eastern states, this has the potential to not only wash entire crops out, this has the chance to inundate large communities, cut off communities for weeks and cut major highways. This could be a significant and widespread flood on SOME of the solutions and there is no sugar coating it. I cannot be more blunt, I hope I am wrong.
FLOOD RISK SOUTH AUSTRAIA
Flooding is a chance for the eastern areas of the state with the highest chance of riverine flooding and flash flooding under the developing tomorrow with the area to watch between Port Augusta to Leigh Creek through to Cockburn down to Renmark and over to Yunta. This is where the heaviest rainfall is to be found. It eases Thursday.
FLOOD RISK NEW SOUTH WALES AND VICTORIA
Flooding is a risk across many areas of the state during the coming week with the highest risk over southern and eastern areas, along the slopes west of the divide. There is major flooding ongoing and once again most of the state is under the threat of new or renewed flooding until the weekend. This flood risk may be extended to next week as well IF the models align and keep the rain and thunderstorms going in onshore winds.
FLOOD RISK QUEENSLAND
Flood risk increasing once again through the latter part of this week into the weekend. Starting out in the southwest where flooding has not been recorded. That will be low level minor flooding at this time, but pay attention to thunderstorm warnings for high end flash flooding. Then the flood risk increases over the flood zones with heavy falls this weekend and continuing into next week. This may be expanded to Central QLD as well if the falls verify.
The latest data sets...
The severe weather event dominates the short term with tremendous rainfall forecast for many areas over the course of the next 3 days and some locations may see 5 day totals be over 300mm in NSW and QLD. Remain weather aware. The west is dry, SA becomes drier from the weekend as does VIC. The rain and storms may persist through QLD and northern NSW over the weekend but recycle through to the west of both of these states as high pressure anchors itself in the east. This may form another outbreak of rain and storms for much of NSW and QLD next week and dipping into eastern SA and VIC as a trough emerges from the west. The tropics active but the dry and hot weather continues right through this time.
UKMET - Rainfall Next 7 Days - MODERATE CHANCE
This is unchanged from last night which is good for consistency. Widespread rainfall from eastern SA through northern VIC most of NSW and southern and eastern QLD with scattered heavy falls. Some areas could clear 200mm through this week while others are spared. Otherwise the rest of the nation quiet, drier through WA and over the tropics you are looking at seasonal weather. SA and VIC turn drier this weekend.
The weather is expected to remain unsettled with showers and thunderstorms for much of QLD, NSW and northern and eastern VIC for now. Unsettled weather develops over WA born out of a heat trough and this could spark thundery showers as moisture surges south into this feature. The tropics seeing it's wettest week of the season so far in early December as tropical waves run over the northern parts of the country. A large scale rainfall event may develop from the instability out of the west merging with the eastern trough, leading to more excessive rainfall chances. No drying out to be found for the east.
ICON - Rainfall Next 8 Days - LOW CHANCE
The west quiet and the east is where you will find the rainfall with some areas getting clobbered. This model does not quite render the data correctly and the coverage of rainfall in the east is likely to more widespread than advertised here.
CMC - Rainfall Next 10 Days - LOW CHANCE
Widespread rainfall with moderate to heavy falls, this model has less rainfall and would be a better outcome for many of the farmers in the east and south. Fingers crossed but I find it unlikely still. Quiet out west and the tropics are seasonal.
EURO - Rainfall Next 10 Daysv- HIGH CHANCE
The numbers through SA and VIC shifting around a bit as expected with the low pressure centre still yet to intialise. The rainfall over the east carries a higher degree of confidence and numbers have come up over QLD through the outlook with some areas recording between 150-250mm over the course of the next 10 days and coastal areas into NE NSW also likely to see similar totals. The remainder of the nation quiet and dry and the tropics seasonal.
ACCESS - Rainfall Next 10 Days - MODERATE CHANCE
Concerning rainfall totals for inland portions of QLD, NSW and VIC. This model is suggesting a similar system developing this time next week with equally heavy rainfall potential over the east and northeast. The tropics active, but the upper ridge keeps the west dry and noses into SA for a period. This would result in major flooding.
KMA - Rainfall Next 12 Days - MODERATE CHANCE
This is aligning with ACCESS and Euro and the GFS showing multiple rainfall events beyond this immediate system through the outlook period. This would also result in major flooding. The west dry and settled through to early December. Another rain event is likely for central and eastern SA.
GFS - Rainfall Next 16 Days - MODERATE CHANCE
The rainfall on the GFS is aligning with the above 3 major models which is cause for concern if you live through inland QLD, NSW, ACT and northern and eastern VIC. Flooding is a very decent chance on top of dozens of flood warnings in place right now ahead of this rainfall. The west remains quiet through the 9th of December though inland areas may start to see unsettled weather as troughs deepen.
These data sets are remarkably wet, when you think that there are between them, 116 members all saying the same thing! So this is a concerning forecast for major flood risks.
GFS - Rainfall Next 16 Days (median of 35 members) - MODERATE CHANCE
CMC - Rainfall Next 15 Days (median of 30 members) - MODERATE CHANCE
EURO - Rainfall Next 15 Days (median of 51 members) - HIGH CHANCE
I am leaning more towards this solution though other data is similar.
The flood potential, cooler weather and above average rainfall for the east continues. The weather more tame over the central and western parts of the nation as troughs develop from time to time but high pressure ridging in bringing breaks and the tropics, possibly turning monsoonal mid month.
CFS - Rainfall Next 6 Weeks - MODERATE CHANCE
Watch that monsoonal weather over northern parts of the nation and the east coast continues with this persistent wet signal through until the first week of January.
More coming up from 7am EDT. I will try and cover off as much as I can throughout the coming days, remain weather aware, have the warnings, radar and this page active throughout the period if you live in the east. Hey WA, share the sun and heat with us!!!