Bay Area is about to get cold and windy — here's how low temperatures will get

Breezy conditions ahead

As low pressure moves southeast, high pressure will build near the Oregon-California border. This setup creates a pressure gradient, which will generate breezy winds in the Bay Area on Thursday afternoon through Friday.

Tonight’s low temperatures will be offset by some of these winds but once winds drop off overnight, temperatures across the Bay Area will plummet. This means temperatures after midnight will run below average and fall to the 30s and 40s during the rest of the week, but they will get even colder by Saturday.

The coldest temperatures are yet to come

The arrival of the winds Thursday will help usher in cold air throughout the Bay Area during the days ahead. In San Francisco, high temperatures for the rest of the week will be below average, reaching the mid-50s.

Clearer skies will help temperatures drop further so that the overnight lows by the end of the week drop another 3 to 5 degrees. Places like Santa Rosa will drop to 32 degrees. San Francisco's low could reach 40 degrees.

This cold, dry air will give the region time for floodwaters from recent storms to finally recede. But that may not be the case for residents by the beach.

King tides and coastal warning

Residents on the coast who are still recovering from recent flood damage will be contending with king tides. These tides are set to begin just before 8:30 am Thursday and will will last until Monday.

These high tides will raise another weather risk for coastal residents from the Sonoma coast down to Santa Cruz and could trigger flooding in low-lying areas.

Thursday breakdown

• San Francisco: Lingering rain showers will hang out over portions of the city this morning, with Twin Peaks, Bernal Heights and Mount Davidson likely to see brief bursts from moderate rain bands. All showers across the city will fizzle away before noon, letting daytime highs peak in the mid-50s in downtown and along Market Street between the Castro and Embarcadero. Cooler air will hang around the west side thanks to lingering cold air from yesterday night.

Drier air will then filter down from Sutro Tower and spread outward in the afternoon, clearing out any low-lying clouds on the west side and waterfront. After sunset, moderate dry winds — gusting to 25 mph — will spread into all corners of the city. Skies will continue clearing overnight, allowing temperatures to plummet to the 40s before midnight. Thankfully, the winds will keep temperatures from falling below 40 degrees. Look for some of the warmest air in the city tonight to hang around the Richmond and Sunset districts, where temperatures will hang in the upper 40s.

• Pacific Coast and Peninsula: A few sprinkles this morning across most of the Peninsula will fizzle out before noon, with skies gradually clearing on the coast by the early afternoon and San Francisco Bay by mid-afternoon. Daytime highs will settle in the mid-50s regionwide. A few pockets of cold air will linger along higher elevations of the Peninsula, including Highway 92, where temperatures will struggle to reach lower 50s.

More prominent north winds will then seep into Daly City, Millbrae and Colma after sunset. Some of the windiest spots, including San Francisco International Airport and Half Moon Bay, could see 30 mph gusts overnight. These moderate winds will dip south along 101 into Redwood City, Foster City and Atherton after 8 p.m. and stay in place through the overnight hours. Thankfully, these winds will slow the rapid cooling that weather models are forecasting for the region, meaning tonight’s temperatures along San Francisco Bay and the Pacific coast will get down to the upper 30s to lower 40s while wind-shielded pockets of the inland valleys will drop to freezing.

• North Bay: After this morning’s light showers clear out, sunnier skies will help raise daytime highs to the upper 50s across Marin, Sonoma, Napa and Solano counties. But this warmth will be short-lived as cold, dry air from the Mayacamas Mountains seeps into the rest of the highlands and eventually dips into the Sonoma, Petaluma and Napa valleys along Highways 101, 12 and 29. Winds will pick up after sunset, with gusts peaking around 25 mph by 6 p.m. before gradually dropping off after midnight.

Depending on how quickly winds drop off, pockets of fog might wind up forming along portions of northern Napa and Sonoma counties—including cities like Healdsburg and Guerneville. The same goes for the Marin Headlands, where winds are slated to calm by 1 a.m. This means overnight temperatures will likely fall to the mid-30s, while pockets of the inland valleys farther from San Francisco Bay will easily fall to freezing. Residents closer to San Pablo Bay will end up with warmer overnight temperatures closer to the lower 40s thanks to the bay influence. Some of that warmer air will then seep into Solano County cities like Fairfield and Vacaville, where lows will hover around the lower to mid-40s.

• East Bay: Following some of this morning’s light showers, residents in the East Bay can expect sunnier skies, drier air and daytime highs in the lower 50s today that will quickly fall to the upper 30s tonight. Cold air will sweep the Oakland and Berkeley foothills, Piedmont, Albany and Castro Valley, after 6 p.m. Winds will quickly pick up through 9 p.m., with gusts along the I-880 and I-80 corridors peaking around 30 mph this evening.

By late Thursday night, winds will calm and temperatures will fall to the upper 30s to low 40s for residents along San Francisco Bay. Heading east of I-680 and into the San Ramon and Livermore valleys, cities like Walnut Creek, Antioch and Brentwood will deal with even colder overnight temperatures. Depending on how quickly winds drop off tonight, temperatures will easily fall to the mid-30s, raising concerns for unhoused residents in the valleys.

• South Bay and Santa Cruz: A few sprinkles will linger across the Cupertino hills and East San Jose this morning before finally fizzling away before noon. Sunnier skies will then return to the Santa Cruz Mountains and South Bay this afternoon and allow daytime highs to peak in the mid-50s, though some of the summits in the mountains and foothills will stay closer to the lower 50s. After sunset, winds will pick up to 30 mph along 280, 101 and 17, including portions of Los Gatos, Cupertino hills, East San Jose and the 101 corridor between Morgan Hill and Gilroy. These winds will taper off after 9 p.m. and allow temperatures to drop to the mid-30s across most of the region. Colder pockets of air will settle in the Santa Clara Valley and Santa Cruz Mountains, where nighttime lows will likely fall to freezing.

Some of the warmest areas in Santa Cruz County will be along the coast, where Monterey Bay’s warmer waters will keep Santa Cruz, Capitola and Watsonville closer to the lower 40s tonight.

Gerry Díaz (he/they) and Michelle Apon are San Francisco Chronicle newsroom meteorologists. Email: gerry.diaz@sfchronicle.com Twitter @geravitywave Email: michelle.apon@sfchronicle.com