'It will be kind of a whiplash': Bay Area weather to turn cold and rainy

A warm, sunny winter day in Hayes Valley on March 11, 2020. A warm, sunny winter day in Hayes Valley on March 11, 2020. Photo: Amy Graff Photo: Amy Graff Image 1 of / 24 Caption Close 'It will be kind of a whiplash': Bay Area weather to turn cold and rainy 1 / 24 Back to Gallery

Once all the fog has cleared, Thursday will be the last day to enjoy the spring-like weather that has brought sunny skies and warm temperatures to the San Francisco Bay Area this week. Friday will mark the start of a cooling trend and on Saturday a wet pattern begins.

"Today is the last day of well-above normal temperatures," said Scott Rowe, a forecaster with the National Weather Service Bay Area. "We’re not going to see any middle- to upper-70s after today. We’ll knock off five to 10 degrees for most locations tomorrow."

With a ridge of high pressure over the region, the Bay Area is expected to see temperatures 6 to 12 degrees above normal on Thursday. The South Bay is expected to see afternoon highs in the mid- to upper- 70s and some locations in the North Bay could hit 80. The interior valleys of the East Bay will see mid-70s.

"In San Francisco, temperatures will dependent on your location," said Rowe. "Along the coast it could struggle to hit 60 but the Financial District will see a high of 66 to 67, maybe even 70."

On Friday, temperatures will take a nosedive and on Saturday a storm is expected to drop down from the Pacific Northwest, delivering the first significant rain the region has seen since January.

Rowe said the showers will start in the North Bay and gradually move southward. In San Francisco, there's a 30% chance of rain at sunrise, a 50% chance in the afternoon and once the evening hours hit, a 70% chance.

The rain is expected to continue into Sunday and maybe even Monday and Tuesday for some locations.

"It looks like it will unsettled for several days," said Rowe.

Urban areas including San Francisco will see .25 to .75 inch. Higher amounts of .75 to 1.5 will be possible in the hills and along ridges.

Amy Graff is a digital editor at SFGATE. Email her: agraff@sfgate.com.