In the last days before Christmas, the weather seemed primed to deliver hurricane-style winds, thunder and lightning and sheets of rain as the most powerful wave of an atmospheric river storm appeared poised to slam the region.
That wave won’t hit with full force until Tuesday, according to the National Weather Service. But even on Monday, light showers will dot much of the region. Come Christmas on Thursday, rain is expected still to be falling.
“Overall, (Monday) is kind of a break,” NWS meteorologist Dylan Behringer said. “It’s still gonna rain most of the day, but the intensity won’t be as high. The winds will not be as high. But what we’re going to see is that as we get to Tuesday night and really Tuesday night into Wednesday, that rain is going to pick up and so is the wind.”
All of which speaks to how intense the upcoming wave is expected to be, because rain dropped in the Bay Area throughout the weekend — including quite heavily in some areas. According to the weather service, 10.85 inches of rain had fallen on Mount Tamalpais in Marin County in the 72 hours leading up to 6 a.m. Monday. The weather service also measured about 8.3 inches in northwest Sonoma County, 4 inches in areas of the North Bay Valley and 1½ to 2 inches in the East Bay and Peninsula areas.
Next up comes another 2 to 3 inches of rain Tuesday and Wednesday in the North Bay and Peninsula. Some areas of the East Bay and South Bay that often are affected by the rain shadow that comes with the atmospheric rivers are still expected to get at least an inch and probably more, according to the weather service.
“There’s going to be quite a bit of rain this week,” Behringer said. “Ongoing.”
Along with it will be winds that are set to be destructive, according to the weather service. Gusts may reach as high as 70 mph in the higher areas of the coastal areas, Behringer said.
The weather service late Sunday issued a high-wind watch for all areas of the Bay Area and the Central Coast that will go into effect at 7 p.m. Tuesday and run through 4 a.m. Wednesday. The weather service is anticipating that the winds will drop trees, cause widespread power outages create more difficult travel.
Accompanying that warning is a flood watch that will run through Friday, according to the weather service.
The winds “are going to be as strong as they get,” Berhringer said. “It’s a 12-hour window through the night on Tuesday. It’ll die off on Wednesday on Wednesday. There will be a second push on Wednesday night. But the second push is not gonna be quite as strong.”
In all the rain is expected to fall with some regularity until Friday. Behringer said the intensity of it will start to taper off by then, and that Saturday is expected to be dry the beginning of a drying-out period.