MONDAY MORNING WEATHER - SHOWERS CLEARING THE SOUTHEAST, STORMS IN THE WEST TODAY, RAIN DEVELOPS NE.

OVERVIEW

The large-scale frontal system that worked through the southeast during the past couple of days is now moving towards NZ with the wind pattern relaxing and the air drying out, so showers are thinning out and contracting further south today.


Out west, we have a trough in place and a relatively decent slab of moisture to work with, so the rainfall has been moderate in many areas leading to some happy farmers out there.


Along the east coast, there will be a few nervous people watching the upper low that forms this week, the showery weather is expected to return but to what scale remains to be seen, however the overall pattern is not as vigorous as the floods of June.


SHORT TERM

So, the trough in the west weakens and high pressure moves into the region clearing the skies and merges with a ridge over the Bight, this controlling conditions at the surface into Tuesday. So rather quiet weather developing tomorrow as well.


But above the surface is where you find the mischief, in the form of an upper low that will emerge out of SA and deepen as it crosses into QLD and meets the moisture that is building over the Coral Sea.


The moisture will be drawn into the upper low and rain will likely break out from mid-week and persist into the weekend, with many areas seeing multiple months' worth of rainfall in a sitting. The pattern begins to shift this weekend as the upper low moves away.


Out west there is the chance of further cold fronts moving through with frequent bouts of rainfall with follow up moderate falls.


For the southeast, the dry July continues.


LONG TERM/AREAS TO WATCH

The upper low is forecast to move northeast away from the state later this week with an onshore easterly flow continuing to drive the showery weather for the week into the weekend but likely clearing as the pattern becomes mobile again.


Once we see the pattern become more mobile over the south of the nation, this will help to drag moisture across the nation’s west via the jet stream and possibly feeding into frontal weather. At this time the frontal weather is expected to be too far south to have larger impacts for now on Southern Australia.


As I have shown in recent times, the modelling supports wetter weather coming back into the end of the month into August, but it remains to be seen as the climate drivers have to be in sync and work together to bring the rainfall across the nation from northwest to southeast.


WEATHER VIDEO AM - MONDAY 18TH JULY 2022

FORECAST

Rainfall Next 10 Days

Rainfall is clearing out of the southeast inland as we see a high starting to move in from the west today, and the showers will gradually clear through, with a westerly flow. The wettest part of the nation is likely over the west of the country with ongoing periods of rain and thunder this morning sweeping further east as the trough moves inland, the falls decreasing as the trough weakens. The next major weather maker comes in the form of an upper low that will emerge through western QLD with a deep moisture profile feeding the system, leading to widespread rain developing mid to late week with a few heavy falls about. Severe weather is low at this time. There will be further fronts passing through the SWLD of WA at this time for the remainder of the outlook period. Each of these will bring a burst of rainfall and strong winds with mild temperatures but the weather will not make it into SA and VIC with a large high in place and dry weather continues over the northern tropics.

THUNDERSTORM FORECAST

Thunderstorm Forecast Sunday into Monday

Thunderstorms are possible over a broad area overnight and into Monday with locally moderate to heavy rainfall with thunderstorms. The coverage of thunderstorms will be widely scattered, and they are not expected to be severe. The thunderstorms risk contracts east from the coast from Monday morning and clears the inland during the evening.

MEDIUM TERM FORECAST

July 24th - August 1st, 2022

Moisture Watch

The moisture over the northern parts of the nation is of interest as lingering impacts from the rain event this week will be ongoing in the presence of the upper low that will move over the Coral Sea. This could send moisture back via easterly winds over QLD before sweeping southeast in the jet stream northwesterly winds that return to the NT and Central Australia with a long wave trough moving through WA and into the Bight. That will spread moisture from the Indian Ocean into the SWLD with reasonable frontal coverage, so rainfall could be near or above seasonal.

Rainfall Anomalies

Trimmed back the chance of above average rainfall over the southeast inland, I am not satisfied in consistency from the modelling, however with the chance of more moisture coming back via the easterly winds early in the period, there could be another round of showers for eastern QLD and NSW. Rainfall over the SWLD could be marginally above normal in pockets. Drier bias continues for SA.

Temperature Anomalies

The nice warm up continues ahead of the long wave trough passing over the SWLD of WA. The coldest air with that will stay offshore to the south of the state. Cooler bias continues for the northeast tropics with a higher level of cloud cover and showers in onshore trade winds.

CLIMATE DRIVERS - SOUTHERN ANNULAR MODE

The SAM is sitting in a weak positive phase currently and that will support the rainfall to kick off over the eastern inland this week before the SAM turns back towards neutral values. There are some members that are suggesting the positive phase will continue into August which would keep drier weather going over Southern Australia.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.


12Z Euro Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

Refer to video for more information and the model comparison and context in this low confidence forecast period in the presence of the upper low out east.

12z Euro Precipitable Water Anomalies - Next 10 Days

The moisture values are increasing over QLD and NSW in the days ahead as the flow pattern eases from the west and tends into the southeast then east and northeast, helping to project the deeper moisture profile sweeping into the coastal areas and into the upper trough leading to the widespread showers and areas of rain developing over QLD and coastal NSW. The west also seeing some regular bursts of moisture working through the westerly wind profile there where cold fronts will continue to weaken and pass through. There is a lot of moisture sitting over the Indian Ocean that is being used over in the west but not further east as the pattern won't allow for the cold fronts to pick up the moisture further east. Dry season conditions continue over the northern tropics.


12z Euro Rainfall Accumulation - Next 10 days

Refer to video for more information

12z GFS Rainfall Accumulation - Next 10 days

Refer to video for more information

12z CMC Rainfall Accumulation - Next 10 days

Refer to video for more information

12z Euro Rainfall Accumulation - Next 15 days

Refer to video for more information

12z GFS Rainfall Accumulation - Next 16 days

Refer to video for more information

More coming up throughout the day on the systems bringing rainfall and when we can expect the block to break down.