MODELS AND ALL THINGS RAINFALL

A tricky forecast as the pattern becomes slack, the troughs begin to form and take up their semi permanent residence over inland portions of QLD, NT and WA, heat lows on the board, an upper high over the southeast and deep moisture circulating around the nation.


Tricky forecasting indeed!


Lets take a look at the short, medium and longer term data to see what the suite is suggesting.


SHORT TERM

The short term is dominated by the strong cold front and low pressure system over the SWLD of WA which will send in a large rain band across the west tomorrow. That will extend inland. The other major area of rainfall will be about eastern QLD and northeast NSW with thunderstorms and a moderate area of rainfall through eastern NSW with a southerly change, some of that rainfall seeping into the southeast inland east of the divide and over the ACT. Tropics look active for the week ahead.


UKMET - Rainfall Next 7 Days - LOW CHANCE

MEDIUM TERM

This is where we find the forecast becomes more ill defined. We have that frontal passage out of WA hit the blocking pattern over the Tasman Sea and collapse south of SA, but it will leave behind a weak trough and deep moisture through parts of central and eastern Australia but with a ridge close, not much rainfall is expected from it until that trough passes into the east. A low may form on the trough over QLD and one offshore NSW enhancing rainfall again for the east coast and inland areas remain dry. The west turns dry with high pressure and the north is unsettled. The tropical moisture may begin to migrate south as it is pulled into the upper northwest to westerly flow. With a trough passing through WA, this may help to lift this into areas of rain and storms, but some models say not so fast and keep the dry weather going. So with divergence in the modelling, it makes it hard to print out a forecast beyond 5 days with any specificity.


ICON - Rainfall Next 8 Days - LOW CHANCE

CMC - Rainfall Next 10 Days - LOW CHANCE

EURO - Rainfall Next 10 Days - HIGH CHANCE

ACCESS - Rainfall Next 10 Days - MODERATE CHANCE

KMA - Rainfall Next 12 Days - MODERATE CHANCE.

GFS - Rainfall Next 16 Days - LOW CHANCE.

ENSEMBLE DATA

This is going to prove more useful or the medium term with the broader data sets, and watch trends here, rather than the volatile deterministic data that populates your paid and unpaid apps you utilise. It is all repurposed data that you are seeing above. But the one things apps don't do is spell out what I do here and give guidance. So pay attention the forecasts and analysis this week. Things can change rapidly in spring.


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

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

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

LONG TERM

Still have a wet November on the way despite the modelling in the short term looking a little quiet.


CFS - Rainfall Next 6 Weeks - MODERATE CHANCE

Control member shows you the potential nationally, with heavy rainfall events impacting some regions more than others, but the bullseye continues to be the eastern coast of NSW and adjacent inland and into eastern QLD.

More details coming up from 7am tomorrow.