National Weather Service United States Department of Commerce

Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

Automatically generated image showing areas of convective available potential energy.

 

Thumbnail of an automatically generated image showing areas of convective available potential energy. Thumbnail of an automatically generated image showing areas of convective available potential energy. Thumbnail of an automatically generated image showing areas of convective available potential energy.
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CAPE 

This is a surface based Convective Available Potential Energy (CAPE) measurement only.  In the cool season, elevated instability may be much higher than surface based cape.

On average, CAPE of 1000 J/Kg is usually sufficient for strong to severe storms. CAPE of 3,000 to 4,000 J/Kg or higher is usually a signal of a very volatile atmosphere that could produce severe storms if other environmental parameters are in place.

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