The onset of May generally signals the beginning of a weather pattern transition in the Bay Area from one that tends toward wet, cold weather to one that ushers in longer, warmer dry spells.
As National Weather Service meteorologist Matt Mehle put it Thursday morning, “We’re not there yet.”
A cold front approaching the Bay Area is expected to arrive late Friday night and bring more rain through the weekend — likely at least a half-inch in most of the region and as much as an inch in the coastal ranges including the mountains in Santa Cruz and the North Bay — and temperatures that will be especially chilly.
“It’s coming from the Pacific Northwest,” Mehle said. “It’s a pretty typical one. We’ll get pretty decent rain in the Bay Area, and then there will be a bit less as it migrates down toward the Central Coast.”
Mehle said that isolated showers likely will begin falling by 9 p.m. Friday, before more steady rain starts sometime early Saturday. Unlike recent storms and many of the storms that plowed through the region this winter, this one is more likely to bring steady ongoing rain rather than deliver pockets with heavy storm cells.
“This is more of a front that a convective system,” Mehle said. “Those convective systems are the ones that sent out those (heavy) cells. What we’ll see with this one is that the rain may not fall as heavily, but it will be more steady and ongoing.”
It also will be “unseasonably cold,” according to Mehle. Low overnight temperatures may fall into the lower to mid-30s in some of coldest areas, and at least into the low 40s throughout the Bay Area.
“It will be a threat to the unhoused population,” Mehle said. Numerous Bay Area communities offer resources to add unhoused people in cold weather, including San Jose, Palo Alto, Fremont, Alameda County and Santa Clara County.
Winds also will go up, with breezy conditions expected Thursday and Friday giving way to heavier, gustier conditions on Saturday and Sunday. By the weekend, gusts are expected to blow between 25-35 mph.
