DOWNEY — Rain is starting to fall in Southern California Monday morning, bringing high winds and flood watches to parts of Los Angeles and Orange counties and prompting President Joe Biden to declare an emergency in the state.

The flood watch will be in effect from late Monday through Tuesday evening for the Los Angeles County coast, mountains, downtown Los Angeles, the San Fernando, Santa Clarita, San Gabriel and Antelope valleys and inland areas including Hollywood, Compton, Long Beach, Pomona, Downey, Norwalk, East Los Angeles, Culver City, Lakewood and Beverly Hills

It is also in effect in Orange County's coastal areas, inland areas including Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton and Mission Viejo, and the Santa Ana Mountains and foothills.

Some areas of Los Angeles and Orange County could see mild showers after midnight Sunday, but the main precipitation is expected late Monday and into Tuesday, according to the National Weather Service.

The weather service said guidance indicates "good confidence in a strong and powerful storm." Rainfall amounts were on track for 2-4 inches for the coast and valleys, and up to 4-8 inches in the mountains.

As of 4 a.m., there was 0.52 inches of rain reported at Whitaker Peak and 0.43 inches of rain reported at Lechuza Fire Station in the Santa Monica Mountains. There was 0.18 inches reported in Agoura Hills and 0.17 inches reported in Calabasas.

"Heaviest rain likely Mon afternoon-Tue. Impacts include urban and small stream flooding. possible mainstem river flooding & mud and debris flows in and around recent burn areas," the NWS tweeted Sunday. The weather service also warned of gales and high surf expected over the region through Tuesday.

A series of powerful storms are expected to pass through Northern California this week. An atmospheric river event pounded Northern California last week causing flooding, power outages and heavy snowfall in the mountain areas.

Biden approved an emergency declaration for California on Sunday and authorized the Federal Emergency Management Agency to coordinate disaster relief efforts and provide emergency resources, the White House said in a statement.

"We expect to see the worst of it still in front of us," Gov. Gavin Newsom told the Los Angeles Times Sunday. "We're anticipating very intense weather coming in [Monday] and Tuesday morning."

A high wind warning is in effect for parts of Orange County from 4 p.m. Monday until 4 p.m. Tuesday. South to southeast winds from 15 to 25 mph with gusts from 35 to 40 mph are expected in Huntington Beach, Costa Mesa, Newport Beach, Laguna Beach, San Clemente, Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton and Mission Viejo.

Gusts of up to 65 mph were predicted for the Los Angeles County mountains Sunday night, and up to 70 mph Monday. The snow level could drop to 6,000 feet Tuesday.

The Antelope Valley was expected to see gusts up to 60 mph Monday.

The Los Angeles Department of Transportation implemented a road closure of Mulholland Drive between Laurel Canyon Boulevard and Coldwater Canyon Drive in anticipation of the storm activity.

Temperatures will stay cool throughout the week, with highs in the lower 60s. Overnight lows will mostly be in the 40s and lower 50s, but will drop into the 30s in the mountains and high desert.

Health officials did issue a cold weather alert for Lancaster and Mt. Wilson, where near-freezing or sub-freezing temperatures are expected. The alert will be in effect Tuesday through Friday in Lancaster, and Wednesday in Mt. Wilson, according to the Los Angeles County Department of Public Health.

Partly sunny skies will return Wednesday and Thursday, but more rain is possible next weekend, possibly as early as Friday night, according to the NWS.