NATIONAL WEATHER PICTURE - SUNDAY 20TH OF JUNE 2021

Headlines


  • Major rainfall developing throughout the nation this week.

  • Widespread rain with gusty conditions over WA today and tonight with scattered thunderstorms and small hail moving east throughout the SWLD.

  • Showers easing over the east coast as a low moves away.

  • Cold nights returning for the eastern inland as winds turn light and skies clear.

Heavy rainfall has been observed along a cold front that rolled through WA overnight with gusty winds and thunderstorms. Showers behind the rain band are now training over the southwest regions as a front pushes east with a low forming offshore. Some storms may contain heavy winds, small hail and snowfalls developing overnight about the Stirling Ranges.


Showers have gradually eased today over the east coast as the low pressure system in the Tasman Sea begins to lift out to the east. An upper level trough/low may bring another wave of instability increasing showers once again for the eastern seaboard.


Clearing skies over the inland may lead to frost developing over VIC and NSW as well as parts of southern QLD as a high pressure ridge builds over the region.


National Satellite Image - Valid Sunday 20th of June 2021

Upper low off the NSW coast bringing showers today, but the activity is easing with the low moving away. Deep low developing offshore WA with a strong cold front attached, slowly moving through the southwest land division, bringing widespread rainfall. A cloud band is in the process of developing tonight through the outback with rain developing overnight and on Monday. Cold air driving into WA overnight. Clearer elsewhere with dry skies under high pressure.

Deep trough with a low pressure system forming along the front as it is passing throughout the SWLD. Widespread rain and thunderstorms along that boundary moving eastwards. Showers increasing over the southwest with thunderstorms tonight with small hail and squally conditions. Cloud along the jet stream starting to thicken this evening with rain developing overnight through central and interior portions of WA.

Temperatures - Valid Sunday 20th of June 2021

Warm with a nice dry season southeaster over northern Australia keeping this nice and seasonal. Warmer through the interior under stable air as high pressure surges east. Cold along the east coast under strong southerly winds and showers. Cold over the southwest with a cold front passing over the region.

A cold airmass descending over the southwest with well below average temperatures and scattered showers as well as areas of rainfall. Warm over the interior ahead of the front with cloud increasing. Cloud increasing over the central coast with rainfall developing this evening. The coldest day of the year is ont he way on Monday.

Radar - Valid Sunday 20th of June 2021

Rain spreading north and east through the southwest land division with moderate falls. Showers in bands moving in from the west, with local thunderstorms mixed in with small hail tonight. The airmass gets colder overnight with snowfalls developing about the Stirling Ranges tonight. Moderate rainfall for the west will continue.

Widespread showers along the NSW coast have begun to ease, but some locations recorded 50-100mm overnight with 130mm at Wallis Lakes the top score. More moderate rainfall today will ease tonight, but another surge of unstable weather will bring more showers back to the region on Monday.

Rainfall for the next 10 days - Valid Sunday 20th of June 2021

The major rainfall event is expected to sweep the nation this week with the wettest weather over the west to start the week, central areas mid week and the east by the end of the week and the system is on by during the weekend. Another strong wave looks likely to follow next weekend for WA with another band of rain.

GFS Rainfall 00z run - Next 10 days - Valid Sunday 20th of June 2021

CMC Rainfall 00z run - Next 10 days - Valid Sunday 20th of June 2021

Icon Rainfall 00z run - Next 8 days - Valid Sunday 20th of June 2021

Access- G Rainfall 12z run - Next 10 days - Valid Sunday 20th of June 2021


Model analysis and discussion

GFS 00z 500mb/18000ft flow pattern

GFS 00z Surface Pattern with rainfall distribution


Monday 21st of June 2021

Deep upper low over the west coast with a large mass of rainfall and colder weather over the region. Upper ridge over the east keeping southeast areas stable though sending onshore winds into an upper trough over NSW and QLD coastal areas. Heights have come down over northern Australia.

Widespread rain and strong winds over southwest WA with moderate falls. Scattered thunderstorms with hail and gusty winds for the southwest of WA including Perth. Showers over the east coast with moderate rainfall with a trough hanging over the region. Fine over the remainder with frost overnight in the southern and eastern inland. Fine over the north with seasonal conditions.

Tuesday 22nd of June 2021

Deep low and trough over the west will continue to roll east with scattered rainfall along a broad band marching through to SA and the NT as the system peaks. Ridging over the east will be a little stronger than what was analysed which may take some of the sting out of the system as it moves in from WA.

Broad band of rainfall from northwest Australia through the outback into SA with moderate to heavy falls possible. Strong warm northerly winds over the central and eastern parts of the nation with a high moving east. Cold over the southwest with widespread showers and gusty conditions with small hail and thunder continuing for the south coast but clearing over the west coast under a ridge. Fine over QLD though scattered showers possible over the coastal areas south of Mackay.

Wednesday 23rd of June 2021

High amplitude pattern developing with a strong ridge moving slowly east into the Tasman and a deep upper low over the Bight. Strong northerly winds in the warm sector the east keeping temperatures above average after mild nights through the NT and SA. Colder back in the west as a southwesterly flow aloft near a developing ridge. Heights increasing over the NT and Cape York.

Rain band breaking down as it enters into VIC and NSW at this stage on this run thanks to a strong upper ridge in the east, but other runs have shown a much more robust rain and cloud band moving through the eastern inland but will watch trends. Deep low pressure offshore and a little further south of SA keeping the showers strictly coastal with gales along the south coast of WA and SA with damaging gusts possible. Showers decreasing over the east coast under stable air. A few morning showers over the NT and Cape York.

Thursday 24th of June 2021

Deep upper low starting to weaken through SA just west of Adelaide, but still with a severe weather risk. Strong upper high system over the Tasman keeping the low slow moving over the central parts of the nation and forcing the upper trough to weaken and also slow down over the eastern inland. Fine weather over the southwest under a developing ridge, but remaining cool. Humid over the north.

Rain continuing through southwest QLD, NSW and throughout northern and eastern VIC with a cloud band slowly moving east. A deep low south of Adelaide with strong to gale force clockwise winds and showers increasing for the coastal and agricultural areas of SA. Showers over the south coast of WA with cloudy skies in onshore winds. High pressure over the southwest keeping things dry and cool. A few showers, mainly morning over the east coast of QLD and northern coast of the NT.

Friday 25th of June 2021

Deep upper low slowly moving over VIC to be near Melbourne but weakening as a slow moving high over the Tasman begins to force the system southeast rather than eastwards, but other looks have seen this system amplifying encountering more moisture over the eastern side of the nation so will keep watch on that trend. Heights coming down over northern Australia and increasing over southwest Australia with a ridge moving in.

Rain, maybe a few storms, contracting through NSW and into QLD during Friday with some moderate falls, but this run is a little quicker with the trough moving east, thanks to a follow up cold front coming through the southeast with a surface low to be captured by that wave and pushed east. High pressure moving in over the southwest, clearing SA and the south coast of WA. Showers, mainly morning over the NT with humidity values decreasing.

Saturday 26th of June 2021

Upper trough collapses over the east with a low weakening thanks to a blocking pattern over the Tasman. An upper ridge over WA beginning to break down, with heights coming down over much of inland Australia. Heights also coming down over northern Australia. A zonal pattern reestablishing over much of the nation with the low over the east becoming absorbed into the flow.

Rain clearing through QLD with a trough lifting offshore as the upper trough moves off the southeast coast. The low weakens from Friday and dives into the Tasman Sea. High pressure broadening over much of southern Australia. Another front rolling through the southern ocean will approach the southeast of the nation with showers increasing later in the day. Fine and milder weather over the southwest with sunny skies though a shower may develop over the far south at night.

Sunday 27th of June 2021

Deep wave to the southeast of Tasmania with a front attached clearing east. Upper ridge over SA moving east north of this wave. Upper high over the Tasman moving east. A long wave trough on the approach to the southwest of Australia bringing the next wave of weather to the region.

Showers mainly morning over the southeast with a gusty southwest flow over Tasmania and Victoria, easing later. Showers decreasing over SA with clearer weather in the afternoon. Showers increasing over WA later in the day, especially in the southwest, however we have had other runs showing a cloud band developing from the northwest into the western interior ahead of this front. Showers and high humidity vales moving northwest away from Darwin during the morning.

Wednesday 30th of June 2021

Strong upper high over the east, strong long wave over the west, with a high amplitude pattern meaning severe weather may develop over southern Australia with a gusty flow. Heights coming up over the north with humidity values increasing once again.

Strong high over the east keeping things sunny and dry after a cold start. Strong northerly winds developing with a steep pressure gradient in place. Showers over the east coast in onshore winds easing during the day. Widespread showers and gales for the west and southwest along a front with a low passing to the south of WA. Fine elsewhere for now, but cloudy skies over the inland may be in place.

Interesting signals for rainfall moving east into the first part of July. Notice the moisture sitting off WA once again which will be in play after that system over the southeast, so the rainfall opportunities remain in the future on medium term modelling.


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