A powerful storm system is expected to bring winter weather to Southern California weeks early, dropping inches of heavy rain and mountain snow on the region over the Thanksgiving holiday.
The storm will reach San Diego County on Wednesday and is expected to bring up to three inches of rain and up to six inches of snow during its at least three-day stint over the region, NBC 7 Meteorologist Sheena Parveen said. Thunderstorms and flash flooding are also possible.
The impact could be dangerous as millions of motorists hit the road for Thanksgiving, which AAA predicts will be the busiest holiday for travel in 14 years.
"For those three days we will be in ‘Weather Alert’ around here, travel will be hazardous," Parveen said in NBC 7's First Alert Weather forecast. "Thanksgiving Day itself looks very messy travel-wise."
Before the storm even hit Southern California, some flights were already canceled at the San Diego International Airport (SAN) Tuesday morning due to a second storm system hovering over Colorado, where about a quarter of Denver International Airport's 1,500 flights were canceled.
At home, several watches and warnings were issued in anticipation of the forecasted winter weather. The National Weather Service issued a Flash Flood Watch from Wednesday morning to Thursday evening for the coast, inland valleys and foothills. The mountains will be under a Winter Storm Watch from late Tuesday to Friday evening.
During these times, rain could fall at a rate of a half-inch per hour, which has the potential to create isolated flash flooding in steep terrain and areas with poor drainage.
The NWS said the areas of Oceanside, Vista, Carlsbad, Encinitas, Chula Vista, National City, San Diego Escondido, El Cajon, San Marcos, La Mesa, Santee, and Poway should be on alert.
Coastal flooding is also possible as higher-than-usual tides, commonly known as king tides, hit the shore through Thursday. Imperial Beach had signs posted warning residents to potential flooding.
Mountains as low as 3,000 feet could see a dusting of snow, while mountains above 4,000 feet could receive up to six inches, Parveen said. Ranges above 5,500 feet could get up to three feet of snow.
Winds will also increase in the mountains and deserts with some gusts reaching 55 miles per hour, Parveen said.
Drivers were urged to check mountain road conditions before heading out and to travel with an emergency supply kit. While no snow tire requirements were issued as of Monday, it was a possibility once the storm hits.
The California Highway Patrol reminded snow seekers that trespassing on private property to enjoy fresh snow is illegal.
While Thanksgiving is one of the busiest times for travel all year, it's also one of the deadliest, CHP warned.
For that reason the CHP said it will have all available officers on patrol for a Maximum Enforcement Period from 6 p.m. Wednesday to midnight Monday. Officers will be looking out for unsafe, distracted and impaired drivers, with a focus on I-5 from the border to Orange County and I-8 from the coast to Arizona.
The winter-weather storm prompted the Del Mar Thoroughbred Club to cancel races at the track on Thanksgiving Day.
The county isn't expected to dry up until late Friday and some lingering showers and cold weather could stretch into the weekend. Drier conditions are expected next week, Parveen said.