SAN FRANCISCO (CBS SF) – Flooding could be possible in the North Bay and other parts of the Bay Area over the next several days, as a series of El Niño-related storms passes through.

A Flash Flood Warning has been issued by the National Weather Service for parts of Southeastern Sonoma County on Thursday until 8 p.m.

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A Flood Warning was issued for the Russian River near Guerneville by the National Weather Service at around 3:45 p.m. The warning period is open ended and will extend from Friday evening until further notice.

The Russian River is forecast to rise above flood stage by late Friday evening and is expected to rise to as much as four feet over the 32-foot flood stage.

Severe weather in Sonoma County is prompting school closures. Harmony Elementary School, Salmon Creek Charter School and Guerneville School will all be closed Friday due to the heavy rain.

Several parts of the Bay Area are under a Flash Flood Watch issued by the National Weather Service, including San Francisco, the San Francisco Bay shoreline and Peninsula coast.

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Much of the North Bay is also under the Flash Flood Watch, including the coast, Point Reyes National Seashore, interior valleys and mountains.

A flash flood watch in effect from March 10, 2016 through March 13, 2016. (CBS)

A flash flood watch in effect from March 10, 2016 through March 13, 2016. (CBS)

The Flash Flood Watch is in effect from Thursday through Sunday afternoon.

As of noon on Thursday, 3.4 inches of rain fell on Venado since midnight. Santa Rosa saw 1.65 inches of rain and 1.60 inches fell at Mill Valley.

KPIX 5’s Roberta Gonzales said widespread rainfall will slowly spread southward as the day progresses. The entire Bay Area should expect periods of heavy rain on Friday.

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A brief lull in the rain is expected late Friday night into Saturday morning. Two additional systems are expected to pass through the Bay Area during the weekend.

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Additional rainfall will likely result in rising rivers and streams, particularly in the North Bay. Gonzales said the Russian River in Guerneville could reach 31 feet by Friday afternoon, one foot under flood stage. The threat for mudslides, rock falls and debris flows will also increase.