San Francisco’s rainless streak will hit two weeks Monday as a long stretch of dry weather plagues California this January. But there is some hope that by the weekend at least some parts of the state will pick up rain and snow.
For the next five days, the weather pattern will remain unsupportive of any precipitation. Another round of Santa Ana winds will result in an “ extreme episode of fire weather ” for coastal Southern California from Monday through Tuesday. Dry Diablo winds will also push into the Bay Area and clear out the fog, but fire weather concerns in Northern California remain low.
A high-pressure system will build across California from Wednesday through Friday, trapping the dry air mass underneath. Relative humidity will remain very low in coastal Southern California through Friday, with dangerous fire weather conditions.
Dry air and clear skies in wintertime are a recipe for chilly nights but warm, sunny days. Thursday’s high temperatures could push 70 degrees in San Jose and 80 degrees in Los Angeles, about 10 degrees above normal. Nights will be cool statewide, in the 30s and 40s in the valleys with well below-freezing temperatures in the mountains.
Precipitation may finally return to California this weekend when a cold low-pressure system approaches the region.
It’s unlikely to be a big storm, but there is at least a decent chance of precipitation. Lake Tahoe could pick up its first dusting of snow in weeks, and Los Angeles and San Diego may receive their first significant rainfall since last April. Bay Area rainfall amounts look meager, at best, with less than a tenth of an inch expected.
Just how much rain and snow falls will depend on the system’s trajectory. If the system parallels the California coast on its way southward, it will pick up moisture and deposit rain and snow along the coast. But if the system remains over Nevada, precipitation amounts will be light and dry Santa Ana winds will be a bigger concern.
“We’re expecting a closed cut-off low, and those are notoriously hard to forecast,” said Robert Munroe, a meteorologist at the National Weather Service office in Oxnard (Ventura County). Munroe said there is a 50% to 70% chance of precipitation from Saturday through Monday, with a slight chance of thunderstorms.
Regardless of exact precipitation totals, the snow line will probably be very low with this system. Snow could dust Bay Area peaks above 3,000 feet Saturday night, while elevations above 4,000 feet in Southern California may pick up a few inches of snow Sunday.
Despite the encouraging weekend forecast, the overall weather pattern remains unfavorable for soaking storms. Drier-than-normal conditions are predicted statewide through the end of January and into the first week of February. Drought will probably continue to expand across Central and Southern California in the meantime.
Monday breakdown
San Francisco: Lingering fog near the bay shoreline will quickly clear after sunrise as northeast winds push dry air toward the city. Northeast gusts of 25 to 35 mph are expected throughout the day, strongest atop hills. Highs will be close to 60 under clear skies. Overnight lows will fall to the low 40s, possibly dipping to the upper 30s near Cole Valley and Glen Park.
North Bay: A wind advisory is in effect for the North Bay interior mountains until 1 a.m. Tuesday for northerly gusts of 35 to 50 mph. Gusts could reach 30 mph in the valleys in the late morning to midafternoon. Highs will be in the low 60s, about 5 degrees above normal for January. Overnight lows will fall to the mid-30s, with areas of frost possible in the valleys.
East Bay: Blustery conditions are expected in the East Bay hills Monday morning, with gusts up to 40 mph possible. Winds won’t be as strong in the lower elevations, and conditions will be pleasant, with highs in the upper 50s to low 60s under clear skies. Overnight lows will be in the low to mid-30s in interior valleys, including Concord, Walnut Creek, San Ramon and Livermore. Temperatures will fall to the upper 30s in Berkeley, Oakland, Hayward and Fremont.
Pacific Coast and Peninsula: Dry winds will quickly scour out patchy morning fog, resulting in clear skies the remainder of the day. Northeast gusts of 25 to 35 mph are expected, strongest near Half Moon Bay. Highs will reach the upper 50s to low 60s, a few degrees above average for January. Overnight lows will drop to the upper 30s to mid-40s.
South Bay and Santa Cruz: The gloomy weekend fog may linger Monday morning, but drier winds will push in for a sunny afternoon. Gusts around 30 mph are expected in the hills. Highs will be in the upper 50s to low 60s in Santa Cruz County and low to mid-60s in the South Bay. Overnight temperatures will be very chilly, dropping to the mid-30s in the Santa Clara Valley and close to freezing in Gilroy and Morgan Hill.
Reach Anthony Edwards: anthony.edwards@sfchronicle.com ; Threads: @edwardsanthonyb; Bluesky: @edwardsanthonyb.bsky.social
