NATIONAL WEATHER PICTURE - PM EDITION - MONDAY 5TH OF JULY 2021.

Headlines


  • A windy and showery day through the southwest with a significant cold front and cold pool sweeping through the southwest of the nation.

  • Fine and settled through much of the east and south, though cloudy skies hang on over parts of coastal VIC and TAS.

  • Rain still likely to jump over SA Thursday and develop over inland NSW and QLD during Friday, but the coverage still up in the air.

  • Better signals for rainfall developing during late weekend out west, then spreading through nation next week with a wintry airmass developing.


National Satellite Picture - Valid Monday 5th of July 2021.

A strong cold front dominates the nations west with a cold and blustery westerly flow. High cloud is all that remains from a large rain band that formed along the west coast yesterday, high pressure causing this to fall apart, with very little precipitation coming out of this. A cold pool offshore NSW bringing showers offshore. A fine although below average temperatures over the southeastern and eastern inland.

And pay attention if you are living over in the east of the nation as this is the weather expected at some stage next week with blustery conditions and widespread showers over WA continuing through the fortnight and eventually coming into SA and VIC/TAS next week.

Temperatures - Valid 5pm EST Monday 5th of July 2021

Below average temperatures over the southeast and east with a lingering cold airmass drifting further east tonight. High pressure is the dominant force and is causing stable weather despite the cloud cover and colder weather than normal. The wet and cold weather is back over in the southwest but mild ahead of that next front through central and northern WA, with a large temperature gradient about the western inland. Seasonal over the north.

Temperatures - Valid 5pm EST Monday 5th of July 2021

And that is a wintry look with waves of frontal weather bringing fluctuations across the southern coastline of Australia. A cold airmass over the southwest will extend further east on Tuesday with that trough bringing a cooler shift on Friday for the east after a few milder days.

Radar - Valid 5pm EST Monday 5th of July 2021

Bands of showers and gusty winds through the south of the nation near a cold air pool is expected to move further east and southeast and ease this afternoon. Severe weather risks are reducing along the west coast and will ease about the south coast tonight. Otherwise it is mostly dry elsewhere through the nation.

Rainfall for the next 10 days - Valid Monday 5th of July 2021.

Assigning a low confidence forecast for the eastern inland with the lead trough and subsequent developments later in the week. Otherwise showers increasing over the southeast and southern coastal areas during Sunday with that rain slowly graduating northwards through the outlook period next week. The west...wet wet wet. And wet over Tasmania exposed to the weakening fronts and onshore westerly push and enhancements thanks to topography.


00z GFS Rainfall for the next 10 days - Valid Monday 5th of July 2021

Rainfall still expected to be most widespread over through WA with heavy falls in excess of 150mm possible. Watch that moisture that is still flirting to come ashore and give the southern inland a better go of the rainfall odds after this period. Showers increasing over southern SA and VIC during the weekend. Rainfall breaks out over eastern inland of NSW, but the trough and low tonight forecast to go east rather than south, and just like that, heavy falls of 100mm for the southeast turns to 0mm. That will change again. Dry elsewhere over the north under high pressure.

00z Euro Rainfall for the next 10 days - Valid Monday 5th of July 2021

Rainfall starting to shift further east than south through the eastern inland later in the week for NSW and QLD. This will see southern areas at this stage miss out, and given that the upper level winds are dominant out of the northwest/west that makes sense. Still some chance of the system cutting off, so it is not set in stone. Heavy rainfall for the west to continue for the next 10 days and the moisture continues to increase off the west coast, eventually that will spill through the nation next week. Showers increasing for the southern coastal areas of SA and through VIC during Sunday with the first in quite a series of cold fronts.

00z CMC Rainfall for the next 10 days - Valid Monday 5th of July 2021

Moisture feeding through the interior is the biggest shift in the CMC run tonight which is interesting considering the GFS model has lost it a bit this evening. Rain heavy over the southwest is a high chance with a similar rainfall coverage for the region. But in the east, it cannot identify the trough and loses it as it crosses Friday into the weekend, which I don't buy. This model has better rainfall for the southeast of SA and western VIC so fingers crossed that is right!


Model discussion and analysis - Valid Monday 5th of July 2021


00z GFS 500mb/18000ft flow pattern

00z GFS Surface pressure pattern and rainfall distribution


Tuesday 6th of July 2021

Upper level trough finally moves away from the east coast with a blocking pattern ending over NZ. A strong long wave continues to ravage the southwest with significant winter weather moving through the region. Dry although cooler than normal through much of the nation with areas of high cloud over the inland.

High pressure over the east clearing the majority of the southeast and east and extending a stable ridge through the remainder of the inland back through to northwest WA. A strong long wave trough sending a strong front towards the southwest with showers turning to rain with moderate to heavy falls possible later in the day.

Wednesday 7th of July 2021

Ridging over the southeast controlling the weather through much of the central, eastern and northern parts. Over in the west, a strong long wave trough extending well north over the western interior, bringing windy wet and wintry weather to a large portion of the SWLD.

Rain turning to showers over the southwest with wintry spells of hail and squalls. The rain extending further inland over the SWLD with moderate falls. Cold in the east at first but sunshine under high pressure, the ridge extends a stable ridge right throughout the remainder of the nation with no rainfall expected.

Thursday 8th of July 2021

Strong long wave moving into SA, however the moisture profile becomes limited, so a bit like today, widespread cloud but no rainfall moving through the region. The trough will start to kick off unsettled weather over inland NSW later in the day or Friday, with the ridge moving further east making room for this feature. A weak ridge over WA clearing conditions briefly.

Showers running along the southern WA coast into SA, falling through the Bight as the system loses strength and slides southeast. A high in the east moving further away, with onshore northeast winds bringing a few coastal showers over NSW and QLD. Showers easing over WA with a ridge moving through the north of the region. Fine elsewhere with a stable ridge in place.

Friday 9th of July 2021

Upper trough moves into the eastern inland of NSW with unsettled breaking out through the inland. A large upper high moving east of the nation, but extends a ridge back through to northern Australia. Another strong long wave approaching WA later in the day, with a fast flow zonal pattern setting up over much of Australia.

Areas of rain breaking out over southern QLD but more concentrated through inland NSW with moderate falls over the northern and central inland with the chance of thunderstorms. A low may form along the trough. This run of the GFS has now pushed the system more east of south, so no rainfall expected to reach the southeast inland of NSW after showing heavy falls this morning, but this will chop and change. Late showers with a weak front approaching the southeast of SA and rain developing over southwest WA with moderate falls later with windy weather also returning.

Taking it to Friday night the rain is already leaving the east coast with the low moving offshore, this morning it had the low moving southeast through Canberra and offshore Eden. So lots of divergence continues. Rain and strong winds looks a high chance later this week over WA and that system also spreading east rapidly.

Saturday 10th of July 2021

Upper low moving off the NSW coast with clearing conditions as a high redevelops. A strong long wave moving from WA into the Bight with significant cold air rotating through WA. Seasonal temperatures return for much of the mainland and over the north with an upper ridge in place.

Deep low offshore NSW early Saturday should move away through the day with seas and winds easing. Fine weather over the eastern inland extending right back through the remainder of the nation. A strong cold front moving through the Bight will increase winds over the southeast later in the day with cloud increasing. Windy with showers over the southwest.

Sunday 11th of July 2021

Fast moving flow pattern over the nation increasing by Sunday with multiple waves in the flow. A short wave passing over SA and VIC later with showers developing and strong gusty winds. A long wave over the west coast of WA interacting with moisture offshore bringing more widespread falls later in the day. Seasonal and dry elsewhere.

Showers increasing over southern SA and moving into western VIC with a cold front bringing blustery conditions, possibly gale force. Fine weather over the remainder of the inland with high pressure anchored through the subtropics and extending back through WA. A strong cold front under that moving towards the west coast with rain developing later in the day with heavy falls and gales later.

Monday 12th of July 2021

Shortwave passes through the southeast with a colder airmass to follow. A strong long wave passing over the southwest with wintry and wild weather expected for the southwest in about a week. High pressure continues to roll through on top of the conveyor belt of westerly winds keeping northern Australia dry.

Fine over much of inland Austral and through to the north with high pressure. Showers over the southeast easing and contracting to Tasmania as a northwest flow redevelops. A strong cold front with rain from Sunday continuing into Monday with that rainfall extending inland to the Wheatbelt with moderate falls. A cold airmass to follow with widespread showers. A cloud band may form in response to the front over the Indian Ocean and extend southeast.

That front then crosses into the southeast on the Tuesday with windy wet weather developing across most of the southern states early next week. In this run, GFS does not have the rainfall or moisture in phase with the weather systems to the south but I do encourage you to read this post this morning on that feature as it is a high chance of occurring within this 2 week phase of westerly winds.

And the next day Wednesday, the wave train continues to evolve with fronts racing through bringing more rainfall chances for southern parts of WA, through SA into VIC and NSW. The heaviest rainfall for those areas exposed to a westerly flow, which is the west coast of WA and TAS as well as Alpine NSW/VIC.

Thursday 15th of July 2021

Taking the model out 10 days and that winter pattern strengthens next week with long wave troughs rolling through the southern parts. High pressure continues over the northern half of the nation. Classic winter weather pattern which is in line with the middle of winter.

Note the moisture feeding into the northwest of the nation and the frontal onslaught continues right through to the end of the 10 day period with no let up. Strong front over in WA with more heavy rain and strong winds. A strong front over the southeast with showers, hail and thunder with snowfalls continuing. A brief dry spell in SA between fronts but the rain will return likely the next day from the west.


Lets compare the Euro run with the GFS this evening to see how the signals are looking through the short term.


00z GFS Rainfall and Surface Pressure Pattern the next 16 days - for those wanting to see if the wave train continues beyond the above 10 days.

00z Euro Rainfall and Surface Pressure Pattern for the next 10 days.

I will finish with the earlier post today which showed a much different look on the GFS run for next week, so there is divergence in the modelling for next week and expect changes.


18z GFS Rainfall and Surface Pressure Pattern the next 16 days - Note the large rainfall event emanating over the northwest and drifting southeast. Still quite possible in the current synoptic scale tonight.

Need more weather information - tailored forecasts can be the way to go - email me at karllijnders@weathermatters.org for further details.


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