Vehicles driving through pouring rain on Interstate 5 north in University City. Photo by Chris Jennewein
Vehicles driving through pouring rain on Interstate 5 north in University City. Photo by Chris Jennewein

Updated at 5 p.m. Dec. 22, 2016:

The first of two back-to-back winter storms in the San Diego area has moved on this afternoon, after heavy rain caused numerous traffic accidents and roadway flooding throughout the County.

An even more powerful storm was expected to follow close behind and bring snow to lower levels of the local mountains this weekend.

The East County area has received the most precipitation so far, according to rainfall totals as of midday Thursday, according to the National Weather Service.

Automated gauges in the mountains had collected 2.13 inches of rain on Palomar Mountain; 2.07 in Pine Valley; 2.42 on Otay Mountain; 1.45 at Lake Cuyamaca; 1.53 on Mount Laguna; 1.33 in Julian; and 1.30 in Descanso.

Among the top rainfall amounts recorded elsewhere in the county were 1.61 inches on Mount Woodson; 1.58 at Camp Pendleton; 1.28 in Oceanside; 1.78 at the Tijuana Estuary; 1.81 in San Ysidro; 1.31 in Alpine; 1.24 in Valley Center; 1.04 in Ramona; 1.16 in Encinitas; 1.31 in Chula Vista; 1.10 at Lake Wohlford; and 1.07 in Solana Beach. The storm also delivered .81 of an inch near SeaWorld San Diego, .95 in Kearny Mesa and .99 at Lindbergh Field, according to the weather service.

Flooding was reported in Lakeside and Spring Valley Wednesday night, and early Thursday in San Diego neighborhoods of Mission Valley, Grantville, Palm City and Otay Mesa.

As usual, the wet, windy conditions also were leading to traffic snarls across the county.

A brief intermission was expected between the two storms, with the second poised to hit the region Friday evening.

Forecasters said they anticipated heavy rain, mountain snow and gusty winds across the region that may cause problems for holiday travelers, such as slick roads and lowered visibility, and may affect travel on Interstates 8 and 15.

A winter storm watch for the mountains will remain in effect from Friday afternoon through late Saturday night. Scattered snow showers down to as low as 3,000 feet, strong winds with gusts of 45 to 70 mph and cold weather were expected.

By late Saturday night, 1 to 3 inches of snow could fall in areas between 3,000 and 4,000 feet; 3 to 6 inches from 4,000 to 5,000 feet, 5 to 10 inches from 5,000 to 6,000 feet, 6 to 12 inches from 6,000 to 7,000 feet; and 12 to 18 inches in higher areas.

“Snow levels will start out high, but behind a strong cold front, snow levels will quickly tumble from late Friday through Saturday,” according to the weather service. “This may bring accumulating snowfall down to the busy highway travel corridors by Saturday afternoon and evening.”

A beach advisory was issued Thursday by the County Department of Environmental Health for beachgoers to avoid contact with coastal water due to contaminated urban rain runoff.

The sheriff’s Department announced plans to beef up law enforcement activity in local mountains in anticipation of county residents crowding the area for recreational snow activities throughout the weekend.

The storm was expected to move out of the region Saturday night and milder and drier weather will follow on Christmas Day, forecasters said.

–City News Service

Chris Jennewein is Editor & Publisher of Times of San Diego.