NATIONAL WEATHER PICTURE - AM EDITION - MONDAY 5TH OF JULY 2021

Headlines


  • Cold and wintry through the west of the nation, a sign of what is to come over the coming 2 weeks across southern Australia. It may be quiet over in the east for now, but pay attention to the west.

  • Cold nights with frosty starts is the theme this week, but there is rain on the horizon later this week over the inland of NSW and parts of QLD and VIC.

  • A cold wintry spell looms for the southern half of the nation as we track through the end of the weekend to this time next week.


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

Largely clear over the east with a large high pressure system moving slowly towards the east. That high pressure system has forced a strong cold front from WA to weaken overnight through the east of the state with a deck of high cloud on the leading edge fanning through the nation. A strong cold front moving into the southwest of WA bringing widespread showers and cold weather over the region with local hail and thunder

Impressive cold pool sweeping through the southwest with another cold front passing through the west and southwest coast this morning. Showers and storms are gusty with damaging winds possible with small hail. Conditions ease later today as this cold pool moves south of the southern coastline again forced southeast by a high out to the east.

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

Cold throughout the eastern inland and up through central Australia, classic winter morning under high pressure. Drier air over the NT has seen temperatures drop under 20C right up to the north coast this morning. The warm spot of the nation, Cape York and over the Pilbara through the western interior.

Its cold through the southern and southeastern states this morning, under high pressure, frost is widespread but a lovely day to follow with light winds. About the southwest falling temperatures under another cold front which will push the milder inland further to the north and east today.

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

Wettest part of the nation will be the southwest of WA. 40mm in the Perth Metro ahead of this next batch of rainfall moves in from the west. Some areas may walk away with 60-70mm possible from this first event before it winds down.

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

Significant rainfall over the west continues this week with multiple long and shortwaves passing through. We have seen with the first from, 40-60mm of rainfall in the west and we have another 4 systems through the next 10 days. A trough over the east expected to bring a burst of rainfall, low confidence remains in the distribution of that rainfall but that system comes Friday and Saturday, then frontal weather increasing for all southern states next week.

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

Heavy rainfall over the southwest coast with falls in excess of 150mm over the SWLD this week. Widespread falls up to 50mm possible throughout a large region. This model is more aggressive in rainfall for the eastern inland with a dynamic trough dumping a month's worth of rainfall over the eastern inland and GFS develops a low off the southeast of NSW with heavy rainfall possible for the southeast of NSW and eastern VIC. Rainfall comes back through the southern states next week.

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

Euro has even heavier falls than GFS with some locations over the southwest of WA expecting 200-250mm under this scenario. Rainfall is increasing up the west of WA later this week with another strong long wave tapping into the moisture out of the Indian Ocean, which brings rainfall through SA late in the run. Rain in the east is less widespread with a weaker trough moving through, and moving through quickly. This model does not develop a low. I think this model is a little too dry for SA and northwest and western VIC.

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

Heavy rainfall looks similar to the other modelling, so a wet week for WA. Similar spread to Euro but heavier falls expected in the east but the intensity and scale clearly uncertain at this time. Fine weather for much of the central interior, though note the moisture surging southeast from the Indian Ocean.

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


00z GFS 500mb/18000ft flow pattern

00z GFS Surface pressure pattern and rainfall distribution


Monday 5th of July 2021

Strong long wave in the west with a fast flow zonal pattern sitting just offshore the southwest. Strong upper high and block over NZ holding up the upper trough offshore NSW. This block is hampering the wintry weather coming across from WA with the long wave there sliding southeast for a good part of this week, which is keeping parts of SA and central interior regions dry.

Strong front moving through the southwest of WA this morning with showers and storms through conditions easing this afternoon. A high over the east keeping the weather dry and settled for large parts of Australia today, though overcast over parts of the southeast with onshore winds, but clearing conditions expected later as winds ease.

Tuesday 6th of July 2021

Strong long wave trough over the southwest with another front rotating through this feature over the southwest with another wintry burst of weather. Otherwise a ridge over the southeast continuing to move steadily east, finally the block over NZ moving eastwards making room for weather out of the west. Upper ridge over northern Australia keeps the weather seasonal.

Rain with moderate to heavy falls and strong and gusty winds through southwest WA with severe weather potential. Otherwise the rest of the nation is dry. Rinse and repeat weather with morning frost and fog over the eastern and southern inland, the fine with plenty of sunshine for most of the nation Tuesday. The only complication will be areas of high cloud sweeping through the nation via the jet stream.

Wednesday 7th of July 2021

Long wave trough moving through WA with the colder weather spreading eastwards through the state, into SA later in the day. Upper ridge over the east coast with settled conditions persisting out east and north.

Showers increasing over the eastern parts of WA with a gusty westerly wind profile moving into SA. Colder air back through the southwest with showery periods and some local hail continuing. High pressure over the southeast continuing to control the weather for inland areas of the east and north. Morning frost and fog likely once again but the temperatures will begin to move above the average through SA and into VIC in a northerly flow.

Thursday 8th of July 2021

Upper trough passing through the central inland of SA but with little moisture with this system through SA, little rainfall expected, just a lot of cloud across the inland. Upper ridge lifting off the east coast. A weak ridge in a zonal flow moving into WA clearing conditions briefly. Otherwise seasonal weather over the north.

Showers easing through WA with the flow stablaising with a weak ridge and northwest to westerly winds easing. Showers across southern SA with a front passing through in a northwest flow. A trough over the inland of NSW will see rainfall break out through southern QLD and most of NSW, with local thunderstorms bringing moderate rainfall west of the divide during the day, and sweeping through to the southeast by afternoon and evening. Fine through VIC and TAS with a mild northerly flow an fine over central QLD through northern Australia.

Rain becomes locally heavy through northern inland NSW spreading through central and southern parts of the state by afternoon and evening, with the chance under THIS scenario, some areas picking up another 1 month of rainfall throughout this spell of rainfall. The rain may clip the northeast of VIC at night before clearing overnight into Saturday morning.

Friday 9th of July 2021

Upper trough moving over the southeast of NSW, perhaps an upper low, with unsettled weather. This is the only model showing it but has been the most consistent out of the suite of products. Another long wave trough bringing the next wave of wet weather for WA. Ridging over the Bight keeping SA dry and another ridge over QLD keeping the north and eastern inland mostly dry following that low pressure.

Low pressure off the east coast steadily moving away from the coast seeing showers and areas of rain clear out of the region during the day. High pressure over the central interior keeping much of SA, western NSW, QLD and the NT dry. Another front passing through the southwest with moderate falls likely and strong to gale force westerly winds returning.

Saturday 10th of July 2021

Upper low lifting away from the east, a weak ridge passing over inland QLD through to VIC with settled weather continuing, but the weather becoming unsettled through western and southern Australia with a long wave passing through with cloudy skies and areas of rainfall steadily moving through WA and into SA later.

Weak upper high over the eastern inland bringing cold night and sunny weather to kick off the weekend. It may shunt the frontal weather from WA further south of the mainland, but that is not clear at this time, with different looks at this weekend. If a low doesnt form over the east, then a stronger front will move through the southern states without being pushed to the southeast with the pattern more zonal, but if the low forms off the east coast, this will push the system approaching from WA southeast away from SA. Something to watch. A low confidence forecast is attached.

Sunday 11th of July 2021

Upper low dissolves and moves away to the east. A fast moving flow pattern developing over southern Australia in line with the SAM trending negative will allow the frontal weather to become more active, with a wave passing south of SA, and a stronger wave approaching WA with a ridge over the central and eastern interior, keeping northern Australia seasonal.

Showers developing for southeast SA and western VIC with a front approaching. More widespread rainfall developing over WA later with a larger scale system approaching. Ridging over the inland with a centre of high pressure passing over southern QLD, keeping the majority of the inland dry for now, but the high pressure is quite weak so moisture can undercut this high pressure and bring patchy rainfall through cloud bands. So that is an element to watch despite the presence of high pressure over these regions.

Wednesday 14th of July 2021

A large scale long wave trough with a wintry flow for southern Australia, so embedded cold fronts driving showers, gales and small hail and thunder with snowfalls down to lower levels from this time next week for a period of 7 days looks likely on the modelling this morning.

Showers from WA through SA then into the southeast and eastern inland with windy weather and well below average temperatures. Snowfalls becoming moderate through Alpine areas. The rainfall will be heaviest about areas that are exposed to a westerly wind regime, these areas usually get their winter rainfall in these set ups.

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

The wavy flow for the next 2 weeks continues, with several fronts bringing waves of rainfall and a period of showers once we lose the low off the east coast over the weekend. So from the weekend we deal with each front on it's merit as they will all bring different amounts of rainfall and northwest moisture may get involved with some of the activity.

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

Fairly similar in the handling of the next 10 days, the only difference is how quickly it resolves the east coast rainfall event during Friday into the weekend, with a weaker and faster system. Then a large scale long wave introduces that wintry spell for southern Australia after this period and it does take it right across the southern parts of the nation through mid month.

Need more weather information? Email me at karllijnders@weathermatters.org for further details about tailored forecasting.


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