Mild Santa Ana Going but Fair Skies to Linger

The Santa Ana winds that arrived with the New Year to banish an unseasonably wet December are expected to depart today, but sunshine and warm temperatures should linger through the weekend.

Frosty nights, low humidity and excellent visibility accompanied the spring-like daytime weather that marked the beginning of 1985 in San Diego. The first Santa Ana condition of the winter was tempered with cold air from the north and an absence of high winds, making it what meteorologists call a cool Santa Ana. It generated warm, rather than hot, temperatures through the week.

It also ended the 10th-wettest December on record--a month when rain overflowed the average seasonal total by 4.18 inches, the National Weather Service said.

Forecasters said 4.55 inches of rain fell last month, bringing the totals for the season that started July 1 to 7.46 inches. January, February and March are normally the wettest months of the year.

The mild Santa Ana condition, which originated in a high-pressure system over the Rocky Mountains and swept over the coastal mountain ranges, dropped humidity in San Diego County to 19% by Thursday.

The low moisture and clear skies created perfect conditions for chilly nights. While daytime temperatures warmed to the 70s, overnight lows plunged to near-freezing. Even deserts received frost this week, and temperatures early Thursday fell to 34 in El Cajon, 38 in Poway and 44 at Lindbergh Field.

The Santa Ana condition should dissipate in the San Diego area as the high-pressure system over the Rockies drifts eastward, allowing the normal, moisture-ladden onshore flow to resume.

Humidity will gradually increase to from 45% to 65% by Sunday, said forecaster Wilbur Shigehara. Nighttime temperatures should warm gradually, he added.

Shigehara said there is a slight chance that subtropical clouds, which on Thursday were hovering about 500 miles off the Southern California coast, will bring high clouds inland over the weekend. He anticipates, however, that sunny skies will prevail.

Daytime highs in the coastal and inland areas are expected in the upper 60s to low 70s. Lows along the coast of 38 to 46 tonight and 42 to 50 are expected Saturday.

Lows inland are expected in the 32 to 42 range tonight, and in the 37 to 47 range by Sunday morning.

Mountain temperatures will be cool--46 to 54 degrees during the day--and down to the 26- to 36-degree range at night.

Desert highs in the 60s today and Saturday should warm to the low 70s by Sunday, but nights will remain cold. Lows are expected in the 33- to 43-degree range through the weekend.