Delta breeze, cooler temperatures might help firefighting efforts in Northern California

A cooling Delta breeze and an increase in humidity are expected to help firefighters get control of wildfires burning across Northern California, Cal Fire said Monday.

A National Weather Service Red Flag Warning was issued over the weekend because of high temperatures and gusty winds, conditions that contributed to the spread of at least a half-dozen fires in Lake, Tehama and Shasta counties.

But a cool Delta breeze swept into the valley overnight, bringing humid air and causing temperatures to drop about 10 to 15 degrees, according to the National Weather Service.

A "great increase" in relative humidity is expected through the night, said Capt. Jordan Motta, Cal Fire spokesman. "An increase in relative humidity means a decrease in fire activity, which should help the containment number grow."

Smoke from Northern California fires and a 162-acre fire in Tuolumne County are not affecting air quality in Sacramento, according to the Sacramento Air Quality Management District.

In the foothills, there is visible smoke in the upper atmosphere, but the smoke pollutants are not at breathing level, the Placer County Air Pollution Control District said.

There was a spike in pollutants at 8 p.m. Sunday, but it dispersed throughout the night, a spokesperson said.

Molly Sullivan: 916-321-1176, @SullivanMollyM

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