MODELS AND ALL THINGS RAINFALL

The models continue to be quite volatile across the board but I will say that the first system is now starting to settle into the central and northern parts of NSW taking the rain bias out of southern NSW and VIC, where days ago there was 1-2 months of rainfall forecast for this region. Now that will be focussed over central and northern NSW, the falls scattered, and some areas will get clobbered. Flash flooding and renewed riverine flooding is a chance.


Thunderstorms will also bring locally heavy falls about NSW and QLD. Thunderstorms will also erupt along a new trough emerging in WA which taps into deep tropical moisture and leads to a strong chance of severe weather later Sunday into Monday.


A broad unstable northeast flow develops next week in the east while out west the trough over the SWLD of WA that taps into the moisture surging southeast from the Indian Ocean bringing the chance of showers and severe storms from WA into SA and then that runs into the first system lingering over QLD and NSW. Rainfall for the eastern states becomes widespread again mid to late week and we need to watch for flood risks.


The potential for a major flood event over a wide area is running very high over NSW and QLD at this stage. I will be watching closely for you.


This forecast will be updated tomorrow.

Lets take a look.


SHORT TERM

The short term dominated by the major rainfall over the east this weekend and another follow event next week. For the west watch the severe weather risks later in the weekend into next week. That could produce heavy rainfall. That moisture will run over SA and VIC mid to late next week. Moderate falls likely. The storms over the tropics are expected to increase in coverage with a larger amount of rainfall expected for the NT and over Cape York. Flooding is a risk for NSW and parts of QLD.


UKMET - Rainfall Next 7 Days - MODERATE CHANCE

2 systems across the nation and it is increasing rainfall from yesterday nation wide. Watch the trends in the coming days in the east.

MEDIUM TERM

Persistent moisture over the east and northeast of the nation with onshore winds will feed a slow moving trough bringing more elevated rainfall chances with the ongoing risk of severe storms and flash/riverine flooding. The further east you are through the east the wetter you will be. Clearance may continue to move east through SA and VIC with a ridge building. The easterly winds across the nation will turn hot over WA with a drier trend following storms in the short term. The tropical weather becoming very active.


ICON - Rainfall Next 8 Days - MODERATE CHANCE

Heavy rainfall over the inland of NSW poses the biggest threat to flooding nationally.

CMC - Rainfall Next 10 Days - MODERATE CHANCE

Heavy rainfall has shifted north in NSW but the coverage is building over the eastern states generally with the second rainfall event. Moisture over the north is deepening and the moisture offshore the NW of WA is expected to play a part in seeding the thunderstorms for inland WA.

EURO - Rainfall Next 10 Days - MODERATE CHANCE

Flash and riverine flood risks are expected to increase over the coming week through NSW and southern and eastern QLD. Some of this may creep further south. Watching the trough over WA during the latter part of the weekend into the early new week. The tropics very active this week.

ACCESS - Rainfall Next 10 Days - MODERATE CHANCE

This is again not impossible and is cause for concern with 300-500mm rainfall areas appearing through NSW and QLD. The grey spots are up to 150mm to 200mm through inland NSW down as far south as Canberra. This is across 2 systems. Heavy rainfall with a deepening trough redevelops over WA later in the weekend into next week and the tropics active.

KMA - Rainfall Next 12 Days - LOW CHANCE

Coverage a little too far north with both systems and too dry through VIC. Has the tropical moisture a little too far east in the Indian Ocean and keeps the trough deep over QLD. Not impossible but this model has been quite inconsistent.

GFS - Rainfall Next 16 Days - LOW CHANCE

Still a little too dry - and I never say that about GFS over 2 weeks very often.

ENSEMBLE DATA

The ensemble data is divergent but wet. The east and north still looking very wet still. The west and south damp, but not as damp.


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

This is wetter more broadly in the east but overall it is too dry for this period across the interior.

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

Probably closer to reality nationally with more moisture about leading to widespread rainfall and thunderstorms developing.

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

Euro starting to pick up the heavier rainfall over inland NSW with this week's activity which will cause flooding over NSW if it verifies. The tropics turning active as well. The interior a little too dry at the moment but will watch closely. The west will potentially see more rainfall than what is shown here.

LONG TERM

Wet....still....


CFS - Rainfall Next 6 Weeks

Further flooding will take us through into January. Ignore the rainfall being lighter over the tropics.

More coming up tomorrow morning and coverage throughout the weekend will continue so stay up to date. No time for a break during this time.



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