December 18th, 2005 was the last time San Francisco was under a Severe Thunderstorm Warning! Our ABC station @abc7newsbayarea catching some great images of the vivid #lightning hitting the bay area overnight. #CAwx #BayAreaweather #BayArea— Dan Peck (@danpeckwx) August 16, 2020
More here: https://t.co/YuLpRn3Xg0 pic.twitter.com/PCO6fhKTrK
The combination of excessive heat and moisture from a tropical storm 1,000 miles to our south set the stage for the dramatic light show.
VIDEO: Compilation of lightning during rare Bay Area thunderstorms
It is not uncommon to have intense heat this time of the year. High pressure is currently set up in the desert southwest, acting like a heat pump sending record breaking heat through much of California.
The wildcard in the forecast is Tropical Storm Fausto, 1,000 miles to our south off the coast of Mexico.
Moisture from the tropical storm is being funneled into Northern California thanks to the clockwise circulation around high pressure with the Bay Area in the direct path.
VIDEO: ABC7 tower cameras capture incredible lightning show across Bay Area
As the moisture interacts with our intense heat, instability occurs and thunderstorms develop.
Thanks to Fausto continually sending moisture into the Bay Area, storms were allowed to live for long periods of time causing lighting to strike for hours. This pattern does not look to change overnight into Monday morning so thunderstorms will remain in the forecast.
Watch the latest AccuWeather forecast and take a look at recent weather stories and videos.
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