Temperatures to Cool as Santa Ana Winds Die

The Santa Ana condition that brought unseasonably warm weather and clear skies to the San Diego area is expected to dissipate today, auguring a return to cooler temperatures and traditional coastal clouds.

The weather is expected to remain mostly clear through Thursday, except for some patchy low clouds and coastal fog early Thursday, according to the National Weather Service.

The weakening Santa Ana could also mean worsened air pollution, particularly in coastal areas in North San Diego County.

“When the Santa Ana starts to break down, we can expect unhealthful conditions,” said Tom Ryan, assistant meteorologist with the county Air Pollution Control District.

That is so, Ryan explained, in part because pollutants blown out to sea during the Santa Ana period may return above the land mass, particularly along the coastal strip. The possible result: a photochemical soup in the coastal sky.

Consequently, Ryan said, there is a possibility of a Stage 1 smog alert today in some North County areas, meaning that persons with respiratory ailments and others sensitive to pollution would be urged to remain indoors. It would be the first such alert this year, Ryan said.

For the past two days, however, the Santa Ana conditions have brought good air quality to the entire San Diego area.

On Tuesday, when the desert-like conditions reached their peak, a high of 90 degrees was recorded at Lindbergh Field, just short of the record high of 92 set in 1976. The normal high temperature for the date is 75 degrees.

Some area highs Tuesday included 98 in La Mesa, 97 in Santee, 96 in Fallbrook and 95 in Chula Vista.

Tuesday’s low at Lindbergh Field was 58 degrees, slightly below the date’s normal of 62. The coolest lows were the 42 degree readings recorded at Santee and on Palomar Mountain.

Coastal highs are expected to be 78 to 84 degrees today, cooling to 73 to 78 on Thursday. Inland areas, as usual, are expected to be somewhat warmer.