The southern polar vortex (stratospheric) heading for an early demise in 2025.

High cloud forming in the lee of Tasmania's Central Plateau.

The September equinox occurs on Tuesday at 04:19 AEST (Monday at 18:19 UTC).

Expect a brisk southerly change with isolated thunder and small hail as this upper feature crosses eastern NSW on Monday.

Seasonably windy days across southern Australia.

Another stupendous Southern Ocean low (939 hPa) between Australia and Antarctica. Spring is conducive because of the heightened contrast between polar and midlatitude air masses - and higher sun elevation makes for great (visible) satellite imagery!

Southern Ocean low south of TAS. Top gust of 148 km/h at the notoriously windy Maatsuyker Island.

September rainfall records across coastal Sydney and the Illawarra, including Sydney's wettest September day in 146 years. Here's the setup. www.weatherzone.com.au/news/sydneys...

The way this system passed the baton between centres as it progressed from the Great Australian Bight to the Tasman Sea.

Low pressure system sweeping along the NSW coastline on Thursday morning.

NSW low pressure system hurdles the Divide to be over the warm Tasman Sea.

Bands of rain and thunder (and a tornado near Young) wrapping around the low over NSW. The system will move over the Tasman Sea tonight, intensifying as it goes, before clearing to the east during Thursday.

Latest projection from BOM ACCESS-C for the dynamic low pressure system developing over eastern NSW. www.bom.gov.au/nsw/warnings/

Thunderstorms associated with the low pressure system developing over SA and NSW.

Low pressure system spinning up over SA → NSW, creating cold and warm fronts on its northern and eastern flanks respectively.

Wheat, canola and other crops coming good across northern VIC and the NSW Riverina.

Thunderstorms dampening the desert across outback SA and NSW.

A midweek warm front over southern NSW will be an interesting oddity. The warm front will produce no dramatic effects on its own, but will be associated with a punchy low pressure system that will bring rain, thunderstorms and wind.

Snow cover on Ben Lomond, TAS from Sentinel-2 on Friday. link.dataspace.copernicus.eu/wpx0

Spring cold front crossing canola-flecked south west WA.

Potential for rain and thunderstorms over central and eastern Australia during the second week of September. NCEP GFS 👈 and ECMWF HRES 👉.

934 hPa low pressure system between TAS and Antarctica.

Kosciuszko National Park on the final day of winter. link.dataspace.copernicus.eu/picy

The coming and going of air masses and jet streams over Australia and New Zealand during winter 2025.

Daytime temperatures were within 1°C of normal across most of Australia during winter 2025 as a whole, while nighttime temperatures were more varied.

Vast area of cold air spreading across south east Australia.

Cold front producing thundersnow over the VIC Alps and NSW Snowy Mountains.

Cold front barrelling across VIC, NSW and the ACT.

Antarctic origins of the air mass arriving over south east Australia.

Westerlies return to the Sydney Basin. ☀️

Subtropical jet stream topping 350 km/h over Australia, thanks to a collision between polar and subtropical air masses.

The air blowing off the Antarctic sea ice (blue) south of WA arrives over south east Australia on Friday.

Here comes a snowy evening for the VIC & NSW high country…

Morning Glory over QLD's Gulf Country on Wednesday.

The air mass arriving over south east Australia on Friday → Saturday looks likely to be the coldest of the year. In numbers: current consensus is for 1000-500 hPa thickness below 528 dam to reach central NSW.

The spring swing.

"Speckle" - or open cell convection - associated with the cold air over WA reaching tropical latitudes.

A meridional ↕️ upper pattern will direct two polar air masses towards Australia this week - the first being over WA on Monday. Close proximity between the cold air and the increasingly warm air to the north will necessarily bring wind.

Cold, unstable air mass over southern WA.

Taste of spring ahead for southern Australia, before winter hits back.

Transient low ensuring every last drop of rain is wrung out over central NSW before drier westerlies return (Sunday).

Cooper Creek floodplain downstream of Innamincka, SA during August between 2020 and 2025. link.dataspace.copernicus.eu/m4tn

Tasman Sea along the NSW coastline resembling a warm bath. Onshore winds are making that tangible for folks in eastern NSW this morning, with the air feeling unseasonably thick. www.weatherzone.com.au/news/the-key...

The upper-level low primarily responsible for the rain over eastern NSW.

Eastern NSW doing what eastern NSW does best.

This upper pattern - a low over northern NSW and a high over the southern Tasman Sea - has been common this decade, producing a significant run of wet years for eastern NSW (and drought further west). www.abc.net.au/news/2025-08...

A ribbon of stability between air masses over the South Pacific.

Hurricane Erin's journey past the Caribbean.

The temperature at Thredbo Top Station (1957 m AMSL) fell to -13.2°C on Monday morning. That's just 0.3° short of the station's coldest temperature on record (-13.5°C on 8 July 1987).

More cold upper air emerging from over the Bight. Showery days ahead for parts of eastern Australia.