LOS ANGELES (AP) — Fire agencies across Southern California took precautions Thursday as meteorological conditions were developing for the first significant blast of seasonal Santa Ana winds, the withering gusts of dry air that suck the moisture out of vegetation and whip flames into conflagrations.

The California Department of Forestry and Fire Protection said it was positioning additional fire engines, bulldozers, fire crews and aircraft in strategic locations.

Recent significant rain in California benefited much of the northern and central areas of the state, but the south remains dry and has the potential for large fires, CalFire Director Ken Pimlott said in a statement.

The Santa Anas were expected to arrive Thursday night after a north wind blowing across the regions shifted to the northeast.

Officials were taking no chances.

Los Angeles County quickly dispatched 150 firefighters and unleashed water-dropping helicopters and airplanes on a midafternoon brush fire that erupted in the canyon-laced Santa Clarita area. It appeared to be under control in less than an hour after burning about 5 acres.

Santa Ana winds are spawned by high pressure over the Great Basin. Descending cold, dry air flows in a clockwise direction across the high desert, then speeds up and warms as it descends through Southern California's mountain passes and canyons and sweeps out to sea. That has often spelled fire trouble for foothill- and wildland-adjacent communities.

Gusty winds were expected from San Luis Obispo County on the central coast south to San Diego County, but the strongest winds — up to 60 mph — were expected in neighboring Los Angeles and Ventura counties, where red flag warnings were posted.

"If fire ignition occurs, the combination of critical fire weather conditions and very dry fuels will create the potential of rapidly spreading fire," the National Weather Service said.

The Los Angeles Fire Department increased its staffing and activated the city's red flag alert system, restricting parking on certain narrow streets in brush areas to keep them accessible to fire engines.

Forecasters said peak wind speeds were expected early Friday but conditions would remain breezy through Saturday.