NATIONAL WEATHER PICTURE - SUNDAY 11TH OF JULY 2021

Headlines


  • Showers easing along the east coast as a low leaves the region

  • Showers trying to develop over SA with a weak front passing through, better chances coming this week.

  • Major rain and storm outbreak for WA once again with the chance of more flash flooding.

  • Rainfall chances become more widespread through southern and eastern Australia this week.


National Satellite Picture - Valid Sunday 11th of July 2021.

Multiple cold fronts embedded within a broad long wave trough south and west of the nation will be the dominant feature of the weather this week across the country. Note the moisture infeed into the system coming into WA. Low pressure has scooted east of the nation now with easing conditions for the eastern seaboard. Weak front moving into Adelaide with a lot of cloud, trying to squeeze out measurable rainfall. Upper high over the north of the nation keeping things hot with severe fire dangers

A closer look at the front coming into SA which has tried very hard to produce rainfall today. The better rainfall lay back with a few storms near a low that has formed west of the front, that may drift into the southeast of SA and southwest VIC overnight into Monday with a few moderate falls.

Temperatures - Valid Sunday 11th of July 2021.

It is baking over northern Australia for the dry season, with mid 30s across many locations of the Top End extending into Cape York and the Kimberly with elevated fire dangers. Near seasonal weather through the remainder of QLD but warming up through the Southern NT into northern SA with northwest winds moving the warmth south and east. Milder back in WA with more sunshine today.

Temperatures have been stubborn to rise today in some locations due to fog areas and low cloud, however note the yellow on the board over northern and western NSW back through SA. That warmth is heading southeast and east for Monday and Tuesday ahead of the next front.

Radar - Valid Sunday 11th of July 2021.

A little light rain with extensive cloud pushing through the Adelaide metro and now extending into the southeast and Riverlands and Murraylands. These falls will be generally less than 1mm and mostly virga. A better cluster of showers and thunder sits southwest of Kangaroo Island this afternoon. That will hold better rainfall prospects from Kingston south to Mt Gambier.

Rainfall for the next 10 days - Valid Sunday 11th of July 2021.

Major front over in the southwest of WA brings another round of moderate to heavy rainfall during Monday with the chance of flash flooding. Showers will continue right through the week over in WA. Another major rainfall event at the end of the period will engulf more of the west coast with moisture surging southeast from the Indian Ocean. A weak front and low over the southeast bring light rainfall through most of southeast Australia during Monday with more widespread rainfall developing from Tuesday with a strong cold front with more showery periods developing during Thursday with another strong cold front coming through Friday with another band of rainfall.

00z GFS Rainfall - Next 10 days - Valid Sunday 11th of July 2021.

Still not much change in the guidance for rainfall over the coming 10 days - with the only shift I am seeing that we are now getting stronger signals for widespread rainfall later in the period associated with a large scale system moving into WA that may bring more widespread rainfall to southern and eastern Australia after this period.

00z Euro Rainfall - Next 10 days - Valid Sunday 11th of July 2021.

Very similar rainfall spread through the winter westerly. Some heavy falls about southwest and the southeast highlands. Up to 3/4s of the monthly rainfall for southwest VIC and parts of southern coastal SA in this sequence.

00z CMC Rainfall - Next 10 days - Valid Sunday 11th of July 2021.

Rainfall similar in spread to GFS and the Euro, but it has got a little too much west of Canberra which is always an issue for the model. Rainfall is increasing off WA during the latter part of the run, similar to GFS but is slower in bringing it through. Between now and then, the westerly wind regime will be in full control.


Model Discussion and Analysis - Valid Sunday 11th of July 2021.


00z GFS Upper flow pattern at 500mb/18000ft

00z GFS Surface pressure pattern with rainfall


Monday 12th of July 2021

Ridging leaving the east coast, upper trough over the southeast bringing unsettled weather through SA into VIC. Strong long wave moving into WA bringing a wave of severe wintry weather. That will push the ridge over the central interior further east during the day.

Showers developing over the southeast of SA into western VIC with a cold front passing over. High pressure over the east ridging through the central interior bringing settled conditions to much of the nation. Upper high over the north keeping the weather hot and dry with elevated fire danger. Strong cold front rolling into the west with heavy rainfall and strong gusty winds.

Later Monday, the front over WA moves further east with a band of rain and strong winds pushing into the the interior. Showers over southeast SA moves into VIC with the chance of a thunderstorm over the southeast. The remainder of the nation remains unchanged with fine weather for most areas.

Tuesday 13th of July 2021

High pressure consolidates over the eastern inland with a warm and strong northwesterly flow developing over the southeast ahead of a fast moving cold front and cloud band. That band will fall apart a bit through the western interior with drier air and the front weakening. A stronger front rotates through southwest WA with widespread showers and storms with gale force winds continuing. Upper high over the north keeping the region dry and hot.

Later Tuesday rainfall breaks out once again over western SA as the front runs into better moisture and the front over southern WA gets another kick along by a trough running into the feature. Showers may develop over coastal SA and through to southwest VIC and Tasmania.

Wednesday 14th of July 2021

Rain through SA Tuesday night into Wednesday morning moves further east out of the state into NSW and VIC with moderate falls developing over the northern slopes in VIC and the western slopes in NSW. Strong and gusty northwest winds developing over QLD and NSW will bring well above average temperatures. A broad long wave trough over the Bight will send up multiple cold fronts keeping the windy and showery weather ongoing for the remainder of the southern states. Remaining hot over the northern parts of the country with an upper high building further.

Thursday 15th of July 2021

Strong long wave passing from WA into SA waters with a series of troughs and cold fronts continuing to rotate around the feature. Very tight pressure gradient over the interior will bring about cloudy skies and patchy rainfall. This area will separate the warm air over the north and the cold over the south. Upper high strengthening over the NT.

Rain continuing over the eastern inland of NSW with moderate falls over the western slopes of the Great Dividing Range, some of that may drift into extreme southern QLD. A broadly unstable westerly wind regime with showers increasing over much of the southern states with embedded fronts being the focal point for rainfall areas through the southern states. A much colder airmass continues to rear up from the southwest over WA with local hail and thunderstorms developing later. Strong to gale force wind warnings will be attached to much of the south. North of the jet stream, warm and sunny through the interior, grading to hot over the Top End with severe fire dangers.

Friday 16th of July 2021

Widespread showers continues for the southeast with multiple fronts moving through the east and south. Some rainfall along a jet stream cloud band may continue for northern NSW and southern QLD. Rain increasing for southern and central NSW ahead of the cold front later in the day. That front bringing gales and widespread showers, hail and thunder for southeastern states, with moderate falls. Snowfalls developing down to 700m later. Showers ease over the southwest thanks to a new high ridging in. A strong upper high keeping the northern parts of the nation hot and dry.

Saturday 17th of July 2021

Deep long wave trough with cold air moving over the southeast with wintry weather continuing. Strong upper high over the north keeping the north hot and dry with severe fire dangers. The west stringing some fine weather together under a flat ridge.

Showery air continues to move through the southeast with a cold and wintry airmass. Local hail and thunder is possible but easing later for VIC and TAS. Snowfalls down to 600m at first rising to 1000m later. High pressure continues to ridge in from the west with showers easing for SA. Fine weather over much of the inland and out west. Hot weather over the NT spreading southwest into WA.

Sunday 18th of July 2021

Showers clearing through VIC during the morning with the airflow turning into the northwest later as the high drifts through to the north of the southeast. Fine over SA. Cloud increasing over the southwest of WA with rain developing later with a front passing through later. Fine weather over the north with above average temperatures continuing. The heat levels coming up over interior WA spreading into western SA. Fine and seasonal in QLD.

Monday 19th of July 2021

Front from WA moves through to the southeast bringing showers and windy weather in about a weeks time with cool conditions returning. Fine weather over much of the interior under a large high. Strong upper high continues over the north of the nation with temperatures above average. Rain and storms offshore WA will move closer to the coast with a large low pressure system offshore.

Tuesday 20th of July 2021

Rain and thunderstorms for WA with moderate to heavy falls under a cloud band. Showers clearing the southeast after moderate rainfall with a front passing through the southeast. High pressure over the central interior continues to move east bringing fine and seasonal weather to the eastern inland but well above average temperatures are expected for northern and western Australia.

Wednesday 21st of July 2021

High pressure over the southeast keeping weather dry in clear in about 10 days time. A large rainfall event continues for the west with a strong front and cloud band moving in. That may bring locally heavy falls to the SWLD once again. Fine weather over the northern parts of Australia with southeasterly winds returning bringing temperatures down but severe fire dangers continuing,.

Friday 23rd of July 2021.

That rainfall from WA will move through SA mid next week and then the eastern inland over the latter part of next week. But it is in the medium term and this is a signal that will be watched this week. So plenty on during the coming 14 days.

Need more weather information? Email me at karllijnders@weathermatters.org for further details about tailored forecasting, climate forecasts for your region and much more.

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