CONVECTIVE RAINFALL HARD TO PREDICT AHEAD OF TIME - LETS LOOK AT ALL THE DATA.

It is that time of year, and you will get sick of me saying this between now and April, but showers and thunderstorms are rendering all rainfall forecasts at a lower confidence, your number will vary from run to run, forecast to forecast, so now we adjust the way we forecast the rainfall.


You will also notice my rainfall bars changing in the range as we move into November to broaden the range to capture the thunderstorm component and warm season rainfall.


Lets get straight to the data tonight.


SHORT TERM

Really quiet conditions for much of the nation during the coming 5-7 days. The only areas to see multiple days of rainfall with a degree of higher confidence is eastern QLD and through the tropics where thunderstorms will be rumbling most days with meandering pressure troughs. For the southwest and southeast, a front and trough here and there will bring the chance of lights showers, tomorrow over the southeast and Monday over the southwest. The moisture from the tropics will try and move south from this time next week ahead of the system out of WA which is being modelled differently by all agencies. So that renders forecasts poor and low confidence.


UKMET - Rainfall Next 7 Days - MODERATE CHANCE

MEDIUM TERM

The moisture from the tropics now dislodges from the tropics and should be entrenched over the southeast and eastern inland of the nation. Some modelling quite aggressive on the coverage of showers and thunderstorms for SA through VIC and southern NSW. Other models are less interested. Again watching trends, watching the blocking pattern over the Tasman, and see whether the pattern can transition from meridional (north-south) to more zonal (west to east). That may start to move things along a bit and lift rainfall chances more broadly. The higher rainfall chances still exist over northern and eastern Australia and across the Central interior.


ICON - Rainfall Next 8 Days - LOW CHANCE

CMC - Rainfall Next 10 Days - MODERATE CHANCE

EURO - Rainfall Next 10 Days - LOW CHANCE

ACCESS - Rainfall Next 10 Days - LOW CHANCE.

This is waaaaaaaaay too wet for the north BUT I will mention that this type of rainfall is not too far away for the north. Let's watch that moisture unfold.

KMA - Rainfall Next 12 Days - LOW CHANCE

GFS - Rainfall Next 16 Days - MODERATE CHANCE


ENSEMBLE DATA

This is again the most useful product to use, these three ensemble data sets are wetter than their deterministic data sets which is interesting so on that basis, expect numbers to fluctuate wildly for the coming 4 days or so.


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

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

I am leaning with this solution

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

LONG TERM

Still expecting that wet run into December - harvest at this stage is looking disruptive and don't think the storm risks will be sitting up through QLD only, that type of weather will shift south. More on that tomorrow.


CFS - Rainfall Next 6 Weeks - MODERATE CHANCE

More tomorrow from 7am EDT.