ALL THINGS RAINFALL AND MODELLING - SOME CONCERN FOR MORE FOLLOW UP DISRUPTIVE FALLS TO HARVEST.

We have a dry and stable airmass over much of the nation, even the tropics getting in on some of that drier airmass leading to a reduction in not only heat levels but rainfall for the coming few days.


But that is all about to change, and from later this week into the weekend with the potential for some heavy falls, but the confidence is low on that detail and so staying close to the forecasts is key as I do think the rainfall totals will increase rapidly across parts of southern and eastern Australia.


Remember the risk of flooding is ever present through this period and further areas of flooding are likely to develop or redevelop along river systems through the nation.

You can read more on this in the Climate Updates.

Lets take a look at the data sets.


SHORT TERM

A cold outbreak bringing showery weather to the southeast tonight is expected to ease and the nation away from the southeast, mainly rain free for the coming 2-3 days. Then we watch the evolution of a trough through inland WA and that progressing eastwards into a better moisture profile building over eastern Australia. Meanwhile another shot of moisture is expected to develop from the northwest of Australia and feed part of the trough hanging back over WA next weekend. So I am anticipating the rainfall numbers to bounce around a bit in coming days under this complex pattern. The weather getting wetter as we go through the coming weekend and into the medium term.


UKMET - Rainfall Next 7 Days - LOW CHANCE.

MEDIUM TERM

The moisture is expected to linger, deepen and become more widespread over northern and eastern parts of the nation. This will lead to follow up rainfall. There is evidence that moisture may recycle throughout the central of the nation as well leading to widespread rainfall redeveloping over areas that have experienced record rainfall so far this November. The weather will no doubt turn more stormy through this period but be prepared for weather to quickly turn severe with heavy rainfall leading to more flooding over central and eastern parts of the nation. It is a tricky and dynamic forecast and continues to chop and change so stay on top of details. We have major flooding in pockets in some parts of the nation and this will likely increase.


ICON - Rainfall Next 8 Days - LOW CHANCE.

CMC - Rainfall Next 10 Days - MODERATE CHANCE.

Has the rainfall distribution correct a little too dry in the east.

EURO - Rainfall Next 10 Days - MODERATE CHANCE

ACCESS - Rainfall Next 10 Days - MODERATE CHANCE.

KMA - Rainfall Next 12 Days - LOW CHANCE

GFS - Rainfall Next 16 Days - LOW CHANCE

ENSEMBLE DATA

Back to these data sets as we look for some consistency in the rainfall signals off the models, but they are trending wetter as we go through November and into December. I am leaning more towards CMC on this one.


GFS - Rainfall Next 16 Days (median of 35 members) - LOW CHANCE

Too dry - but has the bias correct across northern and eastern Australia. Also watch southern WA for more above average rainfall.

CMC - Rainfall Next 15 Days (median of 30 members) - HIGH CHANCE

Widespread rainfall coming in from the northwest of the nation with the tropical moisture offshore the northwest of the nation will be lifted into widespread rainfall for interior parts of the nation which will spread southeast and east.

EURO - Rainfall Next 15 Days (median of 51 members) - MODERATE CHANCE

Very close agreement with CMC but does not verify the moisture over the NT and QLD as well.


LONG TERM

Additional rainfall this heavy poses a significant threat to the flood risks over inland areas of QLD, NSW and VIC as well as central interior parts of the nation as we run into Christmas.


CFS - Rainfall Next 6 Weeks

The wet run to New Years continues.

Further flooding is likely under such guidance. Note the models picking up on the tropical weather shifting south, this time through the Coral Sea.

Next update due out after 7am EDT Monday.