San Francisco receives what appears be its first ever tornado warning

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A potent winter storm targeting Northern California this weekend brought what appears to be the first official tornado warning on record for San Francisco on Saturday morning.

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The National Weather Service in the Bay Area issued the warning at 5:51 a.m. based on rotation identified on radar, though a tornado is not confirmed. The warning expired at 6:15 a.m.

“We do have reports of damage, and as a result we are sending a survey crew up to the city today,” said Cynthia Palmer, a meteorologist for the Bay Area National Weather Service office in Monterey, California. “While it’s too early to say definitively that there was a tornado, what we can say is that there was a pretty classic signature on radar this morning.”

While it may be the first official tornado warning for the city, it was not the first tornado for the San Francisco Bay Area, according to UCLA climate scientist Daniel Swain. A weak tornado was reported in 2005 just south of the city, for example.

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“Other more significant tornado events have occurred elsewhere in the Bay Area and [Northern California]; although rare, they are not unprecedented,” he wrote on X.

An intense band of wind and rain with embedded thunderstorms moved through the Bay Area Saturday morning with the passage of a cold front.

An atmospheric river ranking a level 2 or 3 out of 5 in intensity is impacting Northern California, according to the Center for Western Weather and Water Extremes.

An impressive combination of weather watches and warnings blanket the broader region for potential flooding, damaging winds, high surf, heavy snow and even possible avalanches in the Sierra.

Flood watches are in effect until Sunday afternoon, mostly north of San Francisco. The North Bay, which saw record-breaking rain last month, could see up to 5 inches of rain with this storm. There could be flooding of creeks, streams and rivers as well as potential rockslides.

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As the storm combines with unusually high tides, large breaking waves as high as 22 feet could pound the shore, possibly flooding beach parking lots and creating dangerous surfing conditions. A high surf advisory is in effect until 7 p.m. Saturday.

At least one to three feet of snow is expected for the Sierra and Southern Cascades, where winter storm warnings are in effect for heavy snow, winds gusting over 70 mph and possible whiteout conditions.

“Travel could be very difficult to impossible,” the Weather Service wrote. “Very strong winds could cause extensive damage to trees and power lines.”

The storm will help to bolster California’s early season snowpack, which got off to a good start in November, but then lost some ground during a prolonged dry spell over the past few weeks. Statewide snowpack sits at 107 percent of average for the date, according to the California Department of Water Resources.

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