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High humidity fuels heavy rain and storms in NSW

Oppressive humidity can be found across much of New South Wales today, and this excessive moisture will be harnessed to produce heavy rainfall and thunderstorms for the rest of the day.

The dew point is a measure of moisture in the atmosphere, and when dew points approach 20 degrees it feels muggy to most people. When dew points get above 20 degrees, it can really start to feel uncomfortable.

In New South Wales today, dew points climbed to near or above 20 degrees across most of the state, apart from the Northern Tablelands and Snowy Mountains. In fact, dew points in the mid-20s were widespread from the Central West Slopes and Plains to the Sydney Metro.

Image: Access-G forecast 2-metre dew points valid at 2pm AEDT Saturday, 7 December 2024

Surface-based convection and other processes will lift this moist air from near the surface, where it will cool aloft and lead to condensation, thereby fuelling heavy rain and thunderstorms.

As you can see in the RADAR loop below, scattered showers and thunderstorms have developed this afternoon across much of the state, particularly in areas where excessive moisture is available. Significant rainfall totals have already been observed, including more than 20mm at Bankstown and Badgerys Creek.

Loop: RADAR and lightning across New South Wales for the 2 hours ending at 2:00pm AEDT

High humidity will continue to fuel heavy rain and thunderstorms across much of the state this afternoon and evening, with the best chance of severe thunderstorms and flash flooding in south-central parts of the state. 

To keep up with the latest warnings, please visit our Warning Summary.