FRIDAY EVENING WEATHER - SHOWERS CONTINUES FOR THE EAST - INCREASING OVER THE SOUTHEAST.

OVERVIEW

We are set to see the back of the upper-level disturbance that has brought widespread rainfall to QLD and falls over 200mm in some locations in recent days, remarkable Winter rainfall for some areas. The weather is set to ease there as the pattern begins to shift into a more seasonal flow pattern, with a zonal westerly wind regime bringing back the chance of frontal weather moving through.


Rain is set to increase over WA tomorrow with a strong cold front with another round of moderate rainfall likely for many Ag Areas.


We also have rainfall developing over parts of SA and VIC in the coming days with weakening systems out of WA tapping into moisture spreading in from NSW and QLD today into these features. The overall trends of the nation becoming wetter as we go through Winter is continuing to unfold as forecast.


SHORT TERM

So, the focus of wild weather shifts from the east of QLD tonight to the southwest of WA on Saturday with the next strong cold front passing through. A pair of weakening troughs over the southeast in the coming 5 days will be encountering the blocking pattern near NZ, and while this sometimes works against rainfall production in SA and VIC, the proximity of the low pressure to the southeast of the nation may actually help slow the rain band down, meaning more rainfall out of relatively weak systems.


So moderate rainfall is possible over SE SA and W VIC on Saturday with a slow-moving trough and falls could exceed 20mm in some areas in this zone. Another weak trough coming through on Sunday may intensify as a low-pressure system begins to form on the trough, and this may see a broader band of rainfall develop over SA and into VIC with mainly light falls for SA and further moderate falls for southern and mountain VIC.


The remainder of the nation is expected to be under the influence of the ridge and so dry and stable weather returning to the east coast and dry season weather to persist over the northern tropics.


Next week looks quieter out west with only weak fronts passing through but there is the chance we start to see stronger systems approach and moisture surge southeast into these features running from west to east across WA. These will be of a lot of interest to SA and VIC by this time next week as they progress eastwards to finish the month and kick off August.


LONG TERM/AREAS TO WATCH

Clearly the areas of interest for many in cropping country in WA, SA, VIC and NSW will be the rainfall that develops from later next week and how much moisture does become detached from the tropics and dumped into the jet stream and flung into cold fronts to produce the broader areas of rainfall and cloud cover.


All the modelling suggests that rainfall will be increasing through the end of the month and into August, but I am hesitant to place specifics down just yet as we have been burned a few times this Winter in SA and VIC by the emergence of anomalous weather events in the east.


At this time, there does not appear to be any blocking patterns forming over the nation or east of the country to disrupt the flow of the moisture and frontal weather out of the west into the east and southeast throughout the end of the month and into August.


WEATHER VIDEO AM - FRIDAY 22ND JULY 2022

FORECAST

Rainfall Next 10 Days

Rainfall continues to build in the forecast packages for the southeast and southern interior of the nation with another strong cold front to bring widespread rainfall over the SWLD during Saturday. The east, showers and the thunderstorms with the upper low should pull away tonight and into Saturday with showers gradually easing for QLD and NSW coastal areas. The rainfall focus tomorrow over the southeast will be focused between Adelaide and Melbourne with the heaviest of the rainfall through Western VIC with a slow-moving rain band. The system that brings widespread rainfall through SWLD of WA will also bring a lot of cloud and patchy rainfall through SA and VIC on Sunday night through Monday with moderate falls possibly developing in VIC with a low forming on the front which will pass through Bass Strait. That whole complex will move out by mid next week. Then we see a more traditional weather pattern emerge through the forecast packages with the wave action over in the far west starting to strengthen from this time next week, deeper moisture being pulled into the frontal weather and this leading to a more active period of weather developing over WA initially and the signals are still strong for that to pass over SA and into VIC and NSW through the end of the month into August.


SOUTHEAST RAINFALL

Rainfall is expected to increase in frequency throughout the period, with the rainfall this weekend clearing through by mid-week but the more widespread and concentrated rainfall chances move in from the end of the period and into the day 10-16 range.

EASTERN RAINFALL

The bulk of the rainfall throughout the period is found in the coming 24hrs is spreading eastwards during the weekend with drier air working back in. Trade winds may bring showers back over the northern tropics and along the northeast Top End but most elsewhere should be dry.

SOUTHWEST RAINFALL

The wettest part of the country is the SWLD with strong frontal weather tomorrow, another few cold fronts developing into the early new week with showers ongoing for the west and south coast. Stronger fronts return into the latter part of the week into next weekend with deeper moisture spreading through the jet stream with moderate to heavy falls developing for the end of the month.

NORTHERN RAINFALL

Not a great deal expected with dry season conditions ongoing.

WEATHER ISSUES

Thunderstorm Forecast Saturday

Thunderstorms are forecast to develop along a strong cold front moving through the region on Saturday with the highest chance along the west and southwest coast on the and immediately in advance of the front. Strong winds and small hail are possible with thunderstorms. But the convection is expected to move eastwards and spread out into areas of rainfall over inland areas with the risk diminishing.

Damaging Winds Risk Saturday

A strong cold front will strengthen the gradient winds in advance of the passage of the front, with northwest winds up to 90km/h along the coast, with squalls to 110km/h as the front passes through and then a period of gale force westerly winds with gusts to 100km/h possible through the west and southwest coastal areas. Conditions will ease by Sunday morning.

CLIMATE DRIVERS - SOUTHERN ANNULAR MODE

The SAM tends back neutral meaning that everything should resume normal operations weather wise, with the westerly wind belt where it should be, the east drying out, more frontal passing over southern parts of the southern states. Some of the outliers/members are tending more negative in the medium term to finish the month.

MEDIUM TERM FORECAST

July 29th-August 6th, 2022

Moisture Watch

The moisture content is largely unchanged in the guidance this morning for the medium range, and we are likely to see rainfall and cloud coverage increasing from the west through this period from WA into SA and through VIC and southern and western NSW. The rainfall and moisture depth depends on the evolution of cold fronts that are embedded in a broader long wave trough that is in the fast flow pattern that looks to develop. If the SAM tends more negative, then the frontal weather could end up being a lot stronger than what we have seen most of Winter. Most elsewhere looking at seasonal values.

Rainfall Anomalies

The rainfall anomalies are forecast to be sitting above normal over western areas of the nation with a very high chance of seeing above average rainfall here and that spreading through southern parts of the nation but with the southeast component to the frontal movement, the best of the rainfall looks to still be out over in the far west of the country. But it will eventually fold over throughout the first half of August with excellent signals for rainfall in areas that need it for the coming weeks.

Temperature Anomalies

The heat engine continues to build throughout this period however with the frontal weather passing over southern parts of the nation, this may knock back the warmest air into the central and northwest interior. The east coast continues to see thicker cloud cover in onshore trade winds, but these will ease. And the colder air following stronger cold fronts as the long wave trough passes through will create an interesting battle ground between the colder air and the warmer air over the nation which may increase instability values moving into August.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me. I am out on the road tonight. More on Saturday.