At least two more weeks of bone-chilling temperatures are headed for the Bay Area.
The National Weather Service is preparing to issue a freeze watch that is slated to go into effect from 1 a.m. Monday through 9 a.m. Thursday as temperatures plummet to as low as the mid-20s in the North Bay interior mountains and valleys, the East Bay hills, the South Bay and down to California's Central Coast. Little respite is in sight: The frigid weather is also expected to "persist through much of next week," the weather service said Sunday.
"Cold conditions will be hazardous to sensitive populations such as unhoused people," the weather service continued in an urgent message on its website, noting prolonged exposure could lead to hypothermia in people, kill crops and possibly damage outdoor plumbing. "Take steps now to protect people, pets, pipes and plants from the freezing temperatures."
What's driving the cold is a high-pressure system arriving from the north in the wake of the storm system that delivered scattered showers and small hail to the Bay Area over the weekend and is now moving south, explained Roger Gass, a meteorologist for the National Weather Service's Bay Area office. Gass said winds are expected to die down as clear skies and radiational cooling during the overnight hours work to preserve the low temperatures, which are expected to remain in the low 40s across San Francisco and in the low to mid-30s throughout most of the region.
The likelihood of record-breaking temperatures is unlikely, Gass said, noting existing record lows hover around the low 20s, but he "can't rule out" some parts of the region. Notably, snow fell over Chews Ridge in Los Padres National Forest on Sunday morning.
As the cold weather continues late into the week, a chance of rain may return to the forecast by Friday. In an emailed alert, the Center for Western Weather and Water Extremes at the Scripps Institution of Oceanography in San Diego forecast the possibility of an atmospheric river making landfall over the West Coast in the next seven days. However, Gass said the weather service's models are in disagreement with one another, and it's too soon to determine timing and amounts of precipitation.