Freeze watch issued for East County valleys

The National Weather Service has issued a freeze watch for Friday and Saturday nights for East County, where cold air will sink into the valleys, dropping temperatures into the upper 20s and low 30s.

The air also will be cooler than normal Friday and Saturday nights in San Diego, falling to 45 degrees, or about six degrees below average.

“People in East County should take measures to protect sensitive plants, but we’re not expecting the sort of hard freeze you get when temperatures are 22-25 degrees,” said Mark Moede, a weather service forecaster.

Daytime highs will be in the mid-to-upper 60s through until Sunday, when temperatures will rise above seasonal levels for three or four days.

The county is experiencing the tail of a slow-moving Alaskan storm that dropped just over one-third of an inch of rain along the coast on Thursday and Friday, and roughly three times as much across some valleys and mountains. The system also produced about 3 inches of snow at Palomar Mountain, and at trace of snow in places like Julian.

Since Nov. 1, San Diego’s Lindbergh Field has recorded 1.52’’ of rain, which is 0.51’’ above normal. Forecasters say the precipitation appears to be part of a fairly routine fall pattern. The strong El Nino that has developed in the equatorial Pacific is most likely to produce heavy rains in January, February and March.

Sample of rainfall for 48-hour period ending at 2 p.m. on Friday: Palomar Mountain, 0.90’’; Descanso, 0.81’’; Pine Hills, 0.76’’; San Marcos, 0.45’’; Oceanside, 0.39’’; Encinitas, 0.37’’; Carlsbad, 0.36’’; Montgomery Field, 0.32’’; Lindbergh Field, 0.26’’.