Gov. Newsom declares state of emergency for Southern California ahead of Hilary

A tropical storm is forecast to barrel into the coast of San Diego Sunday afternoon.

Light rains are anticipated Saturday night and will progress into the morning. The eye of the storm is projected to hit between 3 p.m. and 6 p.m. Sunday.

RELATED: Latest Hurricane Hilary coverage, safety tips and more

As the storm moves through, heavy rains will come in followed by strong winds of 50 mph sustained in San Diego and up to 70 mph in the mountains. Excessive flooding is expected. San Diego County was expected to begin feeling the headwinds of Hurricane Hilary late Saturday, ahead of widespread rain and wind Sunday and Monday, according to city officials.

Hilary was at Category 2 strength Saturday afternoon off the coast of Baja California and was expected to further weaken to a tropical storm by the time it reaches Southern California, but forecasters say the storm will still pack quite a punch.

"Heavy rainfall leading to areas of flash flooding is expected through the afternoon in our mountain and desert areas," the National Weather Service's San Diego office said Saturday. "Chances of widespread, heavy rain will continue into Sunday, when heavier and more widespread rain is expected."

Forecasters expected tropical moisture Saturday evening, leading to areas of showers and thunderstorms pushing westward overnight. The impact of the storm will peak from Sunday morning through Sunday evening. Rain chances begin to taper off through Monday evening for most areas, according to the NWS.

Some areas in the mountain and deserts could see over 2 inches of rain per hour during the peak storm period and 10-12 inches in total, while the coastal region was expected to get up to 2 inches total.

Authorities are advising people to avoid driving during the storm if at all possible.

Rainfall is expected to cause flash, urban and arroyo flooding including landslides, mudslides and debris flows, with dangerous to locally catastrophic flooding expected late Sunday and early Monday.

Gov. Gavin Newsom met with San Diego Mayor Todd Gloria on Saturday at the San Diego Emergency Operations Center to discuss emergency preparations.

"The state stands ready to support communities impacted by Hurricane Hilary. ... We're mobilizing to prepare and respond to this storm," the governor's office said.

Large swells generated by Hilary will affect portions of Baja California Peninsula and Southern California over the next few days. These swells are likely to cause life-threatening surf and rip current conditions.

The watch is the first ever issued in Southern California, according to the National Weather Service. A tropical storm has not made landfall in California since 1939, forecasters said.

The watch covers essentially the entirety of San Diego County, including coastal areas, deserts, mountains and valleys.

The NWS issued a flood watch that will be in effect from Saturday morning through Monday in the San Diego County mountains, deserts, valleys and coastal areas, along with the Riverside County mountains and valleys, the Coachella Valley and San Gorgonio Pass near Banning.

Forecasters said the heavy rains could result in excessive runoff that might flood rivers, creeks and streams and cause debris flows in recent burn areas.

"In addition to the rainfall and flooding threat, another concern is the potential for strong east winds Sunday and Monday," according to the NWS. "The wind threat will be more dependent on the track of Hilary. Should Hilary have a more westerly track, the wind threat would likely be greater, and if the track is more easterly, the threat would be less.

"The combination of heavy rainfall, the potential for flash flooding, and strong winds could very well make this a high-impact event for Southern California."

The U.S. Navy ordered San Diego-based ships out to sea Saturday morning to protect them against the storm. Those vessels included the carrier USS Nimitz and the destroyer Halsey.

The city of San Diego was preparing for Hilary by placing "no parking" signs in low-lying or flood-risk areas, especially crossings around the San Diego River. Stormwater Department crews will also be cleaning storm drains and inlets with a history of debris buildup, street sweeping to reduce trash and pollutants from entering waterways, and monitoring 15 pump stations and more than 46,000 storm drains citywide for any issues.

Sandbags were also available in limited supply and can be picked up at recreation centers centrally located in each City Council District. Residents with identification showing proof of residency can receive up to 10 empty sandbags.

The National City Fire Department and Public Works had provided over 1,500 sandbags before running out. The city's Public Works department was working to prepare the storm drain systems to handle the expected rainfall. The National City Police Department has deployed a homeless outreach team to notify those living on the streets about the hurricane conditions.

Starting Sunday morning, the North County Transit District is reducing service on all modes of transportation. In addition to limiting service, NCTD is providing mutual aid to Amtrak and Metrolink passengers by allowing them to ride any Coaster Train. Amtrak and Metrolink have both reduced their service for Sunday in San Diego County. Schedules and service levels are subject to change based on weather conditions and impacts.

Further bus and train information can be found at GoNCTD.com/Now.