A freak storm has lashed Sydney with strong gusts of wind and heavy rain as temperatures plunged more than 10 degrees in an hour.
The Bureau of Meteorology said the strong storm is whipping wind gusts across Sydney from west to east.
A wind gust of 85 km/h was recorded at Richmond Airport while one of 82 km/h affected Sydney Airport.
Monday December 12th a thunderstorm across Sydney. (9News) Heavy rain sweeps Sydney during freak storm. (Supplied)
The latest figures show 22mm of rain has fallen in just one hour in Sydney at Observatory Hill.
“A trough is generating gusty and fast-moving thunderstorms across parts of NSW,” the bureau said.
Sydneysiders had wind and rain lashing their homes and some people said it looked like the rain was falling sideways.
At 9am Sydney reported temperatures above 32 degrees, but just two hours later they were 19 degrees.
A sudden downpour saturated the city during the storm. (9 News)
Storms are expected to reach from Newcastle to Moree and west to Dubbo today.
As soon as the storm swept over the city, it quickly dissipated and temperatures began to rise again just 20 minutes later.
Unpredictable conditions are forecast for the rest of the day as the trough continues to move east.
Although the storm was brief, it has wreaked havoc across the city with T1 North Shore and Western line trains heavily delayed due to urgent repairs to damaged equipment at Milsons Point.
The winds were so strong that a 50-metre-wide tin roof was ripped from a workshop in Mortdale, south of Sydney, and the debris was thrown onto power lines and strewn across the road.
Fire and Rescue NSW said in Drummoyne a tree fell onto the road blocking the Gladesville Bridge.
In Menai, south of the city, the rain was so heavy it caused floodwaters to submerge Alfords Point Road to Old Illawarra Road.
Motorists are warned not to drive on flooded roads.
Skies darkened across Sydney as the storm swept through. (@JosephTheJStar)
As Sydney enjoyed warm and sunny weather on Sunday, a cold front and trough had started to move east causing the sudden change in weather on Monday.
Weatherzone said Sunday that as the cold front moves through it is mixing with warmer air ahead of it, leading to the risk of thunderstorms.
“Warm, moist air moving into the region east of the trough will enhance convective activity along the trough,” the forecaster said yesterday.
“This environment is conducive to producing widespread, possibly severe, thunderstorms across QLD and northern NSW.”
The Sydney sky darkened, a warning of the sudden storm to come