Weather Service issues 'areal flood advisory' for multiple Bay Area locations

The National Weather Service has issued a weather advisory for flooding for part of the Bay Area this morning The National Weather Service has issued a weather advisory for flooding for part of the Bay Area this morning Photo: NWS Bay Area Photo: NWS Bay Area Image 1 of / 29 Caption Close Weather Service issues 'areal flood advisory' for multiple Bay Area locations 1 / 29 Back to Gallery

With a cold front dumping heavy rain over the Bay Area, the National Weather Service issued an "areal flood advisory" for several locations, warning of flooding in urban areas and along small streams. An "areal flood" refers to the build-up and ponding of water in low-lying areas.

The warning is in effect through 10:45 a.m. Thursday for southeast Marin County, northwest Alameda County, northwest San Mateo County, west-central Contra Costa County and all of San Francisco County. (See map for locations in gallery above.)

Flooding is more likely in poorly drained areas with pooling likely on some roadways. "Do not attempt to cross flooded roadways," warns the NWS.

In San Francisco, flooding is expected to be less severe than what occurred in December during a major storm.

ALSO: 'It’s going to be brutal': Snow elevation levels down to 2,000 feet in the Sierra

The cold front from Alaska reached landfall early Thursday and is forecast to move quickly across the region through the late morning. Showers will linger into the afternoon and evening and conditions are expected to be mostly dry after sunrise Friday morning.

Amy Graff is a digital editor with SFGATE. Email her: agraff@sfgate.com.