Rainbow over Rancho Bernardo
A rainbow before the storm: the National Weather Service shared this photo taken Wednesday morning from their office in Rancho Bernardo.

Heavy rain, deep snow above 4,000 feet and low temperatures are coming to San Diego starting late Christmas evening, according to the latest National Weather Service forecast.

“A major change is coming late Christmas night,” weather service meteorologist Adam Roser said. “A colder system is making its way down the California coast from the Gulf of Alaska, bringing lots of rain in a storm likely to go through Friday night. Then, we might possibly have another storm system coming in early next week.”

Roser said the expected rainfall “is looking heavy with gusty winds along the coast and inland up to 30 mph.”

The winter storm is expected to impact the region starting Christmas afternoon and increasing later that night, possibly causing flooding in county areas when travelers might hit the roads following Christmas Day celebrations.

A winter storm watch, indicating the potential for heavy snows and reduced visibility in the mountains, will be in effect from 6 p.m. Wednesday evening to 6 a.m. Friday, according to the weather service.

Accumulating snow will cause travel delays on Interstate 15 in the Cajon Pass, Interstate 8 in the San Diego County mountains, and on many  secondary roads across the mountains and the High Desert through Friday morning.

Highs Thursday will be 56 to 61 along the coast, 54 to 59 in the western valleys, 47 to 52 near the foothills, 38 to 44 in the mountains and 51 to 56 in the mountains.

A colder weather system that made its way down the California coast from the Gulf of Alaska brought lots of rain in a storm on Monday, which largely passed through the county early Tuesday.

Updated at 6:15 p.m., Wednesday, Dec. 25, 2019

Chris Jennewein

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