Cold weather and a chance of rain in these cities
A circulating low pressure area will aid the circulation of deep offshore clouds on Friday. Cold, moist winds from this system could extend the cloud layer inland, increasing the chances of cooler-than-average temperatures and even rain by the end of the week.
The abundance of moisture in the air will increase the chance of intermittent rain. Most accumulations are expected to occur overnight Friday through Sunday, reaching tenths of an inch in San Francisco, the Peninsula, the East Bay Hills and the Coast. This is enough for some residents to see puddles on the sidewalk and roads for the next few mornings.
Calm down the weekend
The cool, moist winds in the sky will keep afternoon temperatures on Gulf Beach about 3 to 5 degrees cooler than average for this time of year. For San Francisco and Oakland residents, that translates to highs in the upper 60s to lower 70s.
Residents across the Bay Area will feel a cold rush of 20 and 30 mph Friday, Saturday and Sunday from 2 p.m. to 6 p.m. This includes beachgoers from Point Reyes to Pacifica and hikers on popular trails like San Bruno Mountain and Tilden Regional Park.
These winds will eventually moisten and cool the air over the outer suburbs by the end of the weekend.
Residents in Livermore, Fairfield and Dublin can expect afternoon highs to drop from the upper 80s on Friday to around 80 on Sunday. Temperatures will also drop in the Wine Country and Santa Clara Valley as humidity levels rise this weekend, but not significantly. Residents can expect daytime temperatures to reach the lower 80s on Friday and the upper 70s by the end of the week.
The low pressure area is expected to eventually dissipate after Sunday. Look for more sunshine and temperatures to slowly return to average next week.
Weekend breakdown
San Francisco: Sunset and Richmond residents can expect partly cloudy skies and temperatures in the mid to upper 60s Friday, Saturday and Sunday. Daytime highs in the 70s can be reached for San Franciscans east of Sutro Tower, including Mission, Castro and Noe Valley.
Look for temperatures in the mid to upper 50s after 11 p.m. There is also a chance of fog and drizzle on Friday and Saturday nights.
East Bay: Weather models are predicting daytime temperatures for the Tri-Valley area in the upper 80s on Friday, mid 80s on Saturday and upper 70s to lower 80s on Sunday. Cold conditions will accompany the cold weather, with 20 mph wind gusts possible in the afternoon.
Look for partly cloudy skies, afternoon breezes, and daytime highs in the mid 70s at Gulf Beach on Friday and lower 70s on Saturday and Sunday. Residents on Alameda Island and in Jack London Square can look for cool daytime temperatures in the upper 60s and 20 mph gusts from 2 p.m. to 8 p.m.
Intermittent fog and drizzle are expected over the next few nights, which will reduce visibility at times. Look for temperatures in the lower 60s in the water and upper 50s inland.
North Bay: Weather models predict an accurate cooling trend for residents of the Napa, Sonoma and Petaluma Valleys. Occasional fog and breezy afternoon conditions will cause daytime temperatures to steadily drop from the lower 80s on Friday and Saturday to the upper 70s on Sunday. The Wine Country’s foothills have the highest chances of rare fog, drizzle, and drizzle.
Continuous clouds are available for coastal residents. An afternoon breeze will regulate temperatures and keep daytime highs in the 70s. Sunny skies along the Highway 101 corridor will bring warmer temperatures into the lower 80s on Friday and Saturday in San Rafael and Novato. By Sunday, daytime highs across Marin County are expected to only reach the mid 70s.
Overnight, look for spotty drizzle, inland fog and temperatures in the upper 50s.
Pacific coast: The marine layer will make way for fog to travel through this weekend. Residents in Daly City, Pacifica and Half Moon Bay can look for partly cloudy skies in the afternoon and daytime temperatures in the upper 60s.
San Bruno Gap residents can expect occasional fog and daytime highs in the lower 70s. There is a more pronounced cooling trend in the southern branch of the peninsula. Residents in Redwood City, Menlo Park and Palo Alto can expect daytime temperatures to drop from the upper 70s on Friday to the mid 70s on Saturday and lower 70s on Sunday.
Expect patchy fog and drizzle along most of the coast and Gulf Shore the next few nights with lows in the mid to upper 50s.
South Bay and Santa Cruz: Santa Cruz and Santa Clara County residents can expect a cold trend this weekend. Dense morning fog will be followed by partly cloudy skies and daytime temperatures in the upper 70s on Friday and mid-70s on Saturday and Sunday. San Jose could look for daytime highs in the lower 80s on Friday to drop into the upper 70s on Saturday and Sunday.
Visitors to Seaside and Capitola state beaches can expect partly cloudy skies and daytime highs in the mid to upper 60s. Fog is expected to reach shore infrequently.
Overnight, temperatures will generally drop into the lower 60s on the waterfront and upper 50s inland this weekend. Expect intermittent drizzle and dense fog in the mountains along Highway 17 and the immediate coast.
Contact Gerry Diaz: gerry.diaz@sfchronicle.com; Twitter: @geravitywave
