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

Headlines


  • Rain spreads from WA through SA today, reaching central and eastern districts this afternoon and this evening.

  • Wild weather persists about parts of southwest coastal WA.

  • Rain developing for NSW and VIC on Wednesday with moderate to heavy falls about parts of elevated terrain.

  • A colder burst of weather expected later this week over the southeast with more rainfall.

  • The heat continues over the NT with above average temperatures persisting and very high fire dangers.


Satellite Picture - Valid Tuesday 13th of July 2021.

Large scale low pressure system is propelling the northwest cloud band through the nation. The rain band is on the western flank of the high cloud shield, crossing through WA/SA border this morning. Showers and cold gusty winds are impacting the southern and western coastal areas of WA. A trough clearing Gippsland this morning, and clear weather over the eastern and northern parts of the nation.

A rain band is moving into far western parts of SA with a cold front that is steadily moving east. A lot of high and middle level cloud is leading the rain band, there are showers falling to the north of Glendambo and up the Stuart Highway, but mainly to the west of the highway this morning. Rain will spread east today, with the coverage of rainfall increasing.

Widespread showers over the western and southern coastal areas, with some of those showers squally with small hail and thunder. Thunderstorms have brought damaging wind gusts during the past 24hrs. Most areas have recorded 20-40mm from the event with isolated falls over 50mm so far. Rainfall has extended inland with 10-20mm over parts of the Gascoyne and southern interior with rainfall ongoing.

Temperatures - Valid Tuesday 13th of July 2021.

A seasonal morning through the east, cold again with patches of frost in a few locations. Milder back through northern Australia and quite warm over the far north and northwest with a northwest flow over WA and an upper high leading to above average temperatures through coastal NT and Cape York. And you can spot the fronts over southern parts of the nation.

Warm morning under cloud and windy weather through western SA, that warmer air is spreading east and milder day for much of the south and east today, with increasing high level cloud. Rain comes into Adelaide tonight, western VIC overnight and western and southern NSW during Wednesday morning. So temperatures will be elevated tonight.

Radar - Valid Tuesday 13th of July 2021.

Areas of rain beginning to move through the outback of SA back to the WA border, through the APY Lands and through eastern WA. A few moderate falls have been observed in SA, and you could surmise that is ongoing along the front and under the band of rainfall through the Eucla to Nullabor this morning back through the northwest Pastoral district.

Rainfall for the coming 10 days - Valid Tuesday 13th of July 2021.

Rainfall coming down over WA as we are now seeing more frontal weather behind us than in front of us for the first time in weeks, but the rainfall will increase later this weekend or next week. Widespread rainfall is falling through inland areas of the nation, it is light and patchy though the coverage increases later today over SA. The winter regime will see the rainfall favour those areas exposed to a moist westerly airstream. There is rainfall expected to sweep the west and south next week but I am still not drawing that impact in just yet.

12Z GFS - Rainfall for the coming 10 days - Valid Tuesday 13th of July 2021.

The guidance for rainfall again is largely unchanged this morning, which is good for this week, with rainfall spreading from west to east. Next week again there is good agreement in moisture coming through WA but after that in the medium term is still uncertain even after the models had tightly clustered agreement last night, it is the frontal weather and the timing of those features which will keep impacting the rainfall distribution next week. More on that later.

12Z Euro - Rainfall for the coming 10 days - Valid Tuesday 13th of July 2021.

Like GFS not much change in rainfall spread for the coming 10 days, though it has come into agreement with GFS and brought more rainfall to northern NSW with the first front and moisture drifting in from the west. Starting to get some signals for 100mm falls over southeast SA and southwest VIC with consistent rainfall over the coming 10 days, so perhaps the westerly wind regime may persist through the period. Something to watch as it may open the door for that moisture over WA to come in from the east with frontal weather next week.

12Z CMC - Rainfall for the coming 10 days - Valid Tuesday 13th of July 2021.

Again no change in the modelling for this week with the best of the rainfall on and west of the divide in NSW and through the southern inland of NSW into much of VIC and through a good chunk of SA as well. Another rainfall event is coming to WA later in the weekend or early next week with the moisture continuing to build over the Indian Ocean.

Model Discussion and Analysis


12Z GFS - Upper level flow pattern at 18000ft with surface pressure pattern to follow with rainfall distribution - Valid Monday 12th of July 2021.


Tuesday 13th of July 2021

Upper high moving east through NSW today with a significant long wave trough passing through the Bight bringing gusty weather to WA with wild winter weather continuing. Well above average temperatures persist over northern Australia under a broad upper high that is strengthening. Colder weather spreading east in the wake of the long wave with the flow shifting more southwesterly.

Rain moves through SA and increases in coverage as it reaches the YP and Adelaide region, and will spread to remaining eastern areas tonight. The rain will move into VIC and NSW overnight into Wednesday with a warm night on the way. Before then, mild and windy through the southeast with above average temperatures with an increase in cloud. Showers and windy weather through the southwest of the nation. Gusty conditions with another front passing through later today. Fine over the north with hot conditions elevating fire conditions.

Wednesday 14th of July 2021

Rain with moderate falls over much of NSW, especially west of the divide in a west northwest flow. Rain turning to showers through SA and VIC with moderate coastal falls and the chance of a thunderstorm. Gusty conditions over much of the nation with further frontal weather moving through WA with a pool of colder air rotating through the western flank of the long wave trough over the region later. Fine weather over the north with upper high taking control meaning above average temperatures continue. By Wednesday night, the rain has moved into northern NSW with the showers also easing in scale over the southeast as one front moves east and another builds in the Bight.

Thursday 15th of July 2021

Rain periods continues through northern NSW and along the western slopes as a moist westerly flow runs into the Great Dividing Range with light to moderate falls continuing. Another cold front moves from WA into SA with a cold airmass to follow with temperatures falling away. Severe weather may be possible about southeast areas of SA and into VIC with the passage of this system. A new high moves into WA clearing conditions after 17 days of rainfall for parts of the SW. Fine hot and dry over the north under an upper high.

Friday 16th of July 2021

A very cold airmass moves through southeast Australia, struggling to push into the strong upper ridge over the north of the nation, thus damming the cold air over the southeastern states. A piggy back front with a pool of very cold air will race through VIC and NSW later in the day with low level snow, widespread shower, hail and thunder. This system will be off the NSW coast by the end of the day into early Saturday. That feature may help spur some isolated showers and thunderstorms for NE NSW and SE QLD later in the day as well. Fine weather continuing over WA with a high moving in from the west. And a dry southeasterly surge will move through the southern NT.

Significant snowfalls are possible later Friday into Saturday with a squally southwest to westerly wind regime, widespread moderate rainfall for southern and mountain VIC in the unstable southwest flow. This is where most of the rainfall will come for Central and West Gippsland districts.

Saturday 17th of July 2021

Showers with hail and thunder easing for the southeast states, with a low and strong southwest flow easing from the west. Showers clearing SA with a new high crossing over. Fine over WA with a warming trend with northeasterly winds developing, a nice change. Fine over the north and remaining hot with an upper high, but a southeasterly surge will slowly work north elevating fire dangers.

Sunday 18th of July 2021

Clearing through the southeast with a weak ridge moving in But another front is starting to emerge on the charts for later in the day, so showers may only clear back to coastal areas of the southeast before increasing later in the day as the front approaches. Fine over much of the nation with a subtropical ridge in place and hot over the north with elevated fire dangers.

Monday 19th of July 2021

A front slowing down on the approach to the southeast with showers increasing for SA and western VIC with the chance of a thunderstorm. Moderate falls over coastal areas of SA and VIC. Fine weather elsewhere with high pressure moving into the nations heartland. Fine over the north with hot temperatures with an easterly wind.

Tuesday 20th of July 2021

This is where the modelling goes haywire but we will keep it going. Moisture off WA will bring a widespread band of rainfall through the southwest of the nation with a heavy fall or two. Elsewhere, likely clearing over the the southeast with a high moving in, clearing the upper low and cold eastwards. But again this will likely change. Fine and hot over the north.

Wednesday 21st of July 2021.

The rain band moves through the southwest with widespread moderate falls and strong winds. This would be a severe weather look for southwest WA again, but the model confidence this far out becomes a little poor. Fine weather elsewhere with high pressure dominating the east.

By later Wednesday the rainfall moves into the Bight and starts to bring a large cloud band into SA. Strong and gusty warm northwest winds likely to bring a period of above average temperatures across the nation thanks to the heat building over the northwest of the nation.

Thursday 22nd of July 2021

And by Thursday we are seeing rainfall developing through SA and VIC with moderate falls developing. A stronger front to follow may enhance rainfall for the southeast after this period, but we are starting to see the rainfall picking up through the westerly wind belt and moisture play a part once again next week but like I have said, we will have a better handle by this Friday and across the weekend. But the signals for a high amplitude pattern continues with a deep northwest flow with a large thermal gradient developing, that would set up a dynamic weather event.

And the outlook for next week


Rainfall Outlook - July 19th-26th 2021.

Seasonal conditions over the north in the dry season, rainfall may be near normal or slightly above average over the southeast with another wet week over WA.

Temperature Outlook - July 19th-26th 2021.

Above average temperatures for most of the nation next week thanks to the upper high over the north filtering the heat southwards and then the jet stream and northwest winds dragging it southeast.

More weather details throughout today and my latest Climate Outlook will be available for the coming 4 weeks later this morning.


Have yourselves a great Tuesday.

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