Santa Ana winds bring fire risk, frost advisories to Los Angeles and Ventura counties

Powerful Santa Ana winds and warm, dry air will create a dangerous mix of weather conditions that could trigger a fast-moving brush fire with just a spark, the National Weather Service said Thursday.

A red flag warning was issued across the mountains and valleys of Los Angeles and Ventura counties through Friday as wind gusts as fast as 55 mph are expected to blast across the Southland.

“With this expected combination of gusty winds and very low relative humidity, widespread critical fire weather conditions are expected,” the Weather Service’s warning read.

The strongest wind gust overnight was measured at 95 mph at Whitaker Peak at an elevation of 4,120 feet, the Weather Service said. In Malibu Hills, winds topped out at 56 mph and in Santa Monica, winds were measured at 38 mph.

As a low-pressure system continues to flow east toward Nevada, warmer daytime temperatures and dry wind gusts are taking its place, said Todd Hall, a meteorologist with the National Weather Service.

Temperatures will remain in the low 70s Thursday but could climb to the lower 80s downtown on Friday, he said. In areas shielded from the Santa Ana winds by mountains, like the Antelope Valley, temperatures are expected to drop below freezing at night.

Even in areas that bear the brunt of the Santa Anas, the low humidity and clear nighttime skies will quickly cool off the Southland.

“Once the winds drop off you’ll see temperatures drop like a rock,” Hall said.

Joseph.serna@latimes.com

For breaking California news, follow @JosephSerna on Twitter.

ALSO

DWP owes L.A. customers $67.5 million because of rampant overbilling

Cal State will not help deport undocumented students under Trump, chancellor says

Ancient beasts roamed this secret spot in Death Valley, but you probably can’t go