LOS ANGELES (CBSLA.com) — A series of rain storms will hit Southern California beginning Thursday night.

According to the National Weather Service, unusually heavy rainfall will occur Friday as a result of what forecasters say will be the region’s most powerful storm so far this season.

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Early estimates show the coastal and valley areas will get 2-4 inches of rain and the mountains and foothills will receive between 4 and 8 inches.

“Heavy rain is predicted for Thursday night into Saturday,” the Los Angeles County Sheriff’s Department said in a news release Thursday. “This storm is predicted to have more rain than we experienced a few weeks ago. Nearly 4 inches of rain is predicted for our area.”

The first wave of rain will begin along the Central Coast Wednesday, moving south into Los Angeles and Ventura counties by the evening.

A flash flood watch will be in effect from Friday morning through Saturday morning.

Widespread urban roadway flooding is possible, along with flooding in creeks and small streams, and rock and mudslides, especially near canyon roadways.

Officials plan to declare a yellow alert at noon in the neighborhoods below the Fish Fire burn area in Duarte. The warning will require residents to keep streets clear of vehicles, trash bins and other objects that could obstruct emergency vehicles or be washed away in a flood.

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Similar issues could arise in Glendora and Azusa beneath the Colby Fire burn area. Glendora declared a yellow alert Thursday morning. City officials are bracing for 5.75 inches of rain to the Glendora area.  The city has increased both police and public works staffing levels in anticipation of this.

High surf is expected along the coast through Sunday as a result of a large storm-generated westerly swell, with the biggest surf on Saturday.

A high surf advisory will remain in effect from 7 p.m. Wednesday until 7 a.m. Sunday.

Temperatures will be in the mid 60s and low 70s.

Free sandbags are available at Fire Station No. 106 (23004 Roscoe Blvd. in Canoga Park), Ernie Howlett Park, Lomita City Hall, the City Yard (751 S. Alhambra Ave.) and Fire Station No. 61 (350 West Newmark Ave. in Monterey Park).

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