SAN FRANCISCO (KRON) — The National Weather Service calls it an Atmospheric River.

We say it is going to pour starting Saturday and it won’t let up until Monday, and flooding is very likely in places around the Bay Area.

The weather service is predicting San Francisco will get between 3 and 4 inches of rain over the weekend.

Santa Rosa will be hit with between 4 and 5 inches of rain.

WEATHER:San Francisco Bay Area Forecast

The Santa Cruz Mountains could get more than 10 inches of rain in the 72 hour period.

The weather service says this is a once in a 5-25 year storm. They expect to see flooding of roadways, small streams and main branches of rivers.