The National Weather Service office in San Diego said a Pacific storm arriving Wednesday night will drop up to 2 inches of rain along the coast and make travel difficult through the mountain passes.
“A major winter storm is going to affect the region Wednesday evening through Friday morning,” the weather service said. “Near impossible travel conditions are expected Thursday morning in the mountains.”
Snow will be heavy on Interstate 15 through the Cajon Pass and on Interstate 8 in the San Diego mountains. Many secondary roads across the mountains and the High Desert will be treacherous.
Forecasters said heavy coastal rain in San Diego could potentially cause the San Diego River to flood.
Highs in San Diego County on Christmas day before the storm are forecast to be 57 to 62 along the coast, 55 to 60 in the western valleys, 48 to 53 near the foothills, 40 to 47 in the mountains and 59 to 64 in the deserts.
The storm is expected to taper off Thursday night into Friday morning, though another storm is possible on New Year’s Day.
“The storm will move east on Friday with a dry and slightly warmer weekend shaping up,” the weather service said.