NATIONAL WEATHER PICTURE - PM EDITION - TUESDAY 13TH OF JULY 2021

Headlines


  • Areas of light rainfall coming through SA today with a broad cloud band stretching from the northwest of the state right through to border areas with NSW and VIC.

  • Rain developing for inland NSW and much of VIC during Wednesday morning with light to moderate falls expected.

  • Punchy showers developing in the wake of the rain band for SA and continue for WA with the better coverage of wet weather, the further south you travel.

  • A major cold shift expected later this week over southern Australia with more rainfall expected to sweep the southeast into the weekend.

  • Fine weather returns to WA later this week into the weekend.

  • Fine and hot over the NT and northern QLD spreads west into northwest WA.

  • Another rain event looms in the outlook period over WA next week, will it make it east to SA, VIC and NSW?

National Satellite Picture - Tuesday 13th of July 2021

An impressive large scale low pressure system with multiple centres can be seen moving south of the nation with the leading front bringing light patchy rainfall through western SA and eastern WA. The rainfall coverage is expected to increase over the coming 12 hours. Showers and windy weather back behind the front with a series of troughs rotating around the low to the south. Fine weather further east and north, just some high cirrus clouds over the east.

Widespread cloud and light patchy rainfall pushing through SA this afternoon with that coverage expected to increase tonight as fast moving troughs to the south catch up to the front. Showers tomorrow will pack a bit of a punch in a moist mild airmass, but the upper atmosphere is becoming colder and more unstable so thunderstorms are also a risk for coastal areas.

Streams of showers wrapping into the west coast in a vigorous westerly wind regime. The severe weather risk has now passed, but showers can be still squally this evening, before they ease in intensity overnight. They will increase later Wednesday into Thursday with another front passing through which will shift the whole flow into the southwest.

Temperatures - Tuesday 13th of July 2021

Temperatures are well above average over northern Australia, that air being drawn southeast into QLD and northern NSW and northern SA. Temperatures into the mid 20s in these regions. Milder further southeast despite the thickening cloud cover today. Colder back through the southwest with a gusty westerly.

A closer look at that warm digging in from the northwest. This will certainly help get the native flowers out through the region, and elevate pollen levels. The weather cooler tomorrow under cloud and rainfall.

Radar - Tuesday 13th of July 2021

A large low pressure system over the Bight is going to control the weather for large parts of the nation during the coming 2-3 days. Multiple fronts and shortwaves will rotate through the southern states, the coldest front in the seqeunce arriving in the southwest of WA on Wednesday night, SA during Thursday and VIC and NSW Friday. The wet weather contracting east by the end of the week.

Rainfall for the next 10 days - Tuesday 13th of July 2021

Lifting rainfall numbers again for the elevated parts of southeast NSW and northeast VIC with orographic rainfall to persist from Wednesday through Saturday with moderate falls each day. Lifted rainfall for pockets of the Great Dividing Range in NSW up to the QLD border.

Showery weather could be heavy and persistent at times over coastal SA and southern and mountain VIC and western TAS. Rainfall continues for WA today through Thursday morning before returning early next week with another major rainfall event.

00Z GFS Rainfall for the next 10 days - Tuesday 13th of July 2021.

Rainfall events this week look stable in terms of distribution of falls across the southern and eastern parts of the nation. The west dries out with most of the rainfall seen down there for a system that emerges next week, which looks to bring follow up rainfall to southern and eastern Australia next week, that signal is gaining strength on the GFS.

00Z Euro Rainfall for the next 10 days - Tuesday 13th of July 2021.

Rainfall guide continues to remain unchanged through the outlook with vigorous cold fronts passing through with frequency this week as a soup bowl of low pressure passes to the south of the nation. Euro does have follow up rainfall next week over southwest WA and a lager system rolling through towards the end of the run.

00Z CMC Rainfall for the next 10 days - Tuesday 13th of July 2021.

Rainfall looks largely unchanged this week for the east and is in line with other modelling, though CMC does not recognize the system and moisture next week like the Euro and GFS, so it is safer to side with the higher skill score models.

Model discussion and analysis


00Z GFS Upper Flow Pattern and 18000ft with surface pattern and rainfall distribution underneath with my discussion notes.


Wednesday 14th of July 2021

A large and broad scale long wave moving from WA through to SA with a leading trough and front bringing more wintry weather across the nation. The upper high over the east and north keeping conditions warm and dry with above average temperatures.

Rainfall breaks out along the frontal boundary pushing over central and eastern SA, with a moisture plume bringing rainfall back northwest through to the pastoral districts. The rain will move into western NSW and VIC later tonight or early Wednesday morning. Onshore gusty westerly winds producing showers for the southwest of WA. Fine and mild tonight with cloudy skies and more northwesterly winds than previous nights.

The rainfall moves from SA into VIC and NSW with moderate falls developing over the Northeast of VIC, through to the Southwest Slopes of NSW. Fine although cloudy to start for the remainder of NSW but rain pushes in by afternoon. Showers following the rain band over SA will be sharp at times especially by afternoon Wednesday, that activity moving into southwest VIC later.

Thursday 15th of July 2021

Rain continues over the northeast of NSW and extensive showers down the divide to Northeast VIC with a vigorous westerly flow. Some of the falls may be thundery over the southern inland of NSW. Fine weather for VIC at first, with showers increasing later. The front responsible for that bringing a band of rainfall through southern SA with a colder southwesterly change. Hail and thunder developing at night. Fine weather through QLD across the NT and into northern WA with above average temperatures. Showers continue for WA but easing later in the day.

By later Thursday the front clears off WA and moves into SA and note the increasing rainfall over SA and into VIC with moderate rainfall. The rain continues for the eastern inland of NSW along the dividing range in an unstable west or northwest flow. Moderate falls are possible. Fine along the east coast in the shadow of the ranges. Fine and warm weather continues elsewhere.

Friday 16th of July 2021

Broad long wave trough peaking over the southeast of the nation with a wintry mess moving through. Colder air about to sling shot through the southeast rapidly approaching from the southwest. Upper ridge building into WA with more stable weather developing and lighter winds. Upper high over the north strengthening and keeping temperatures above average.

Areas of rain continue over eastern inland NSW with the divide picking up the most falls. Rain increasing later over southern NSW with a front passing through, with the chance of thunderstorms. Rain turning to frequent showers after the front rolls through SA and VIC, moderate falls are possible. Severe weather also a chance through parts of SA, VIC and southern NSW. Fine weather developing over the west coast of WA with showers contracting to the east. Fine and hot over the northern third of the nation under a strong upper high.

Saturday 17th of July 2021

The upper low over the southeast with a very cold airmass will rapidly exit the east during Saturday with an improvement in conditions expected from west to east during the day. The strong upper high over the north continues to hold strong and another ridge builds over WA with settled conditions.

A very cold airmass races through NSW during Friday afternoon and evening with a band of rain, snowfall developing down to lower than 800m during the evening. Rainfall moderate to heavy over the western slopes of the Southern Highlands. Showers increase further over the southeast of SA, southern VIC and western TAS. Heavy falls are possible in parts of south central VIC and western TAS and about the Lofty Ranges in SA. Conditions ease from the west during the day Saturday in SA.

Sunday 18th of July 2021

Improving conditions through the southeast with a moderating southwest flow. The cold air has lifted out into the Tasman and the inland of NSW and SA should return to seasonal conditions and dry out, though still cold over southern inland NSW. Fine weather for a lot of the country away from the southeast where showers will continue in a southwest flow. Warming up out west with a dry few days, the first string of fine weather in nearly 3 weeks. Remaining hot over the north of the nation.

Monday 19th of July 2021

Another trough makes an approach to the southeast of the nation with cold air aloft, bringing showers to southwest VIC and southeast SA potentially moving further inland and north during the day. This is a low confidence forecast as there is no support in the other models for this just yet. Large high pressure taking control of the nations weather, keeping the dry weather going over WA through the interior, over the north and into the eastern inland of NSW and QLD.

Tuesday 20th of July 2021

The upper level trough over the southeast, may begin to interact with moisture sitting off the east coast of NSW and showers may develop in southerly winds, however once again a low confidence forecast applies. Certainly high pressure likely to be over the interior moving east, quite a strong centre. But offshore the west coast, the next rainfall event is looming, deep tropical moisture sitting in the region ready to pounce with a burst of heavy rainfall. But this system also slower in the guidance today.

Wednesday 21st of July 2021

High amplitude pattern develops offshore WA, with a broad and strong long wave trough running into the moisture offshore WA leading to a broad band of rainfall moving through. Upper high over the east moving eastwards through the day. Warm throughout the nation with a northwest flow coming in from northern WA.

Rain areas with thunderstorms, moderate to heavy rainfall continue through Wednesday with a large rainfall event continuing through the southwest. High pressure over the eastern inland moving eastwards sending a long fetch warm northwest flow into the south and east. Upper low offshore the east coast moving away.

Thursday 22nd of July 2021

A large long wave moving into the Bight, beginning to slide a tad to the southeast. Upper high moving east to the Tasman, but the strong upper high over the north continues to produce hot weather for this time of year.

Widespread rainfall moving through WA with moderate rainfall continuing with a colder shift later in the day. Fine and windy through the southern parts of the nation. Remaining fine over VIC, NSW and QLD with well above average temperatures. Winds would be gale force over large parts of the south of the nation.

Strong and squally northwest winds giving way to a westerly change with areas of rainfall with moderate falls passing into SA and VIC. Showers clear through WA with a moderating southwest flow. Fine weather everywhere else, with an upper high over the north and ridging over the eastern inland. Note the anomalous moisture north of the Top End.

Friday 23rd of July 2021.

Heavy rainfall continues through the southeast from Thursday into Friday with a vigorous front with moisture from the Indian Ocean. Follow up fronts through the westerly belt that follows may bring further gusty winds and showery weather. Fine weather elsewhere with above average temperatures through central and eastern inland areas of the nation. Showers clearing through southwest of WA. Fine and hot over the north.


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