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Temperatures near seasonal averages through the next week

Short Term

What a difference a day makes. The continuing development of a cutoff low off the coast of British Columbia has led to a remarkable cooling through the evening and overnight hours, the return of a marine layer of around 500-1000 feet, and a stratus deck over the coastal regions and through the Petaluma Gap and the Golden Gate. As of midnight, temperatures across the Bay Area and Central Coast are running around 5 to 25 degrees below what they were 24 hours prior. Through the day, the aforementioned cutoff low will strengthen as it parallels the coast of the Pacific Northwest. Morning lows will range from the middle 50s to lower 60s in the lower elevations, and the middle 60s to the middle 70s in the higher elevations, while afternoon highs will top out in the middle 80s to the lower 90s in the inland valleys, the upper 90s to the triple digits in the warmest spots of southern Monterey County, the upper 60s to the lower 80s close to the Bays, and the lower to middle 60s along the Pacific coast.

Long Term

The cooling trend continues into the weekend as the cutoff low moves into the Pacific Northwest, allowing for further development of the onshore flow and marine layer to take place. By the weekend, highs will drop into the middle 70s to middle 80s inland and the upper 60s to upper 70s close to the Bays. Breezy onshore winds are expected through the weekend as the passing cutoff low tightens the pressure gradient over the northern half of California. Regarding the SFO-WMC gradient, model output has kept the peak gradient somewhere in the 10 to 15 mb range late on Saturday, with widespread gusts of 25 to 35 mph possible Saturday evening into Sunday morning. Favored gaps, passes, and coastal regions could see gusts to 45 mph.

The trough axis should move into the northern Rockies and the northern Plains for the early part of next week, but the general pattern should remain rather zonal for the remainder of the 7-day outlook, and temperatures should remain more or less stable with highs near or slightly below seasonal averages.