After 17+ Inches Of Rain, 3rd Atmospheric River Ahead For The Bay Area

SAN FRANCISCO — A third atmospheric river is waiting in the wings after an onslaught of rain dumped more than a foot of precipitation over parts of the Bay Area, according to the latest forecasts.

The North Bay bore the brunt of the latest super-soaker, where several areas recorded 15 inches of rainfall since Friday, and an eye-popping 17.3 inches of rain fell on Mount Tamalpais, according to data from the National Weather Service.

Forecasters issued warnings Tuesday for severe thunderstorms and flooding in areas of the North Bay, Peninsula and San Francisco, where videos shared on social media showed wind-whipped rain pouring across city streets. In Sonoma County, floodwaters blocked a portion of State Route 116 near Forestville.

According to the weather service, the storm dumped more than 2.5 inches of rain over downtown San Francisco on Tuesday alone, breaking a daily record set in 1887.

While calmer weather is on tap Wednesday, forecasters are tracking another round of rain Thursday before temperatures take a tumble for a cold and dry weekend.

"By Thursday morning another plume of moisture will reach the coast as a surface low-pressure system develops offshore," the weather service said. "Compared to the atmospheric river on Tuesday, this system will be much weaker in terms of both wind and rain. Rainfall amounts are generally expected to be 0.25 - 1.25 [inches]."

After Thursday's system exits, forecasters expect Friday will serve as a transition day before a colder trend takes hold across the region.

"Saturday morning will start roughly 10 degrees colder than Friday morning," the weather service said. "Many inland areas will drop into the low 30s, and widespread frost advisories are expected. Afternoon highs will only climb into the mid to upper 50s, so it will feel chilly all day, although there will be ample sunshine."

Forecasters predict a pattern of clear and chilly days will stick around through early next week, with early signs for the next round of rain arriving Wednesday.