Los Angeles is about to experience its first widespread Santa Ana wind condition of the fall beginning Wednesday night, bringing with it a "critical" danger of fire from very dry air and high winds, the National Weather Service warns.
The most serious period could be Thursday night through Friday evening when a "fire weather watch" will be in effect with gusty northeast winds and low humidity expected.
"If fire ignition occurs, this Santa Ana wind event will have the potential to bring rapid spread of wildfire due to critical fire weather conditions and critically dry fuels," the weather service said in issuing the following statement:
Gusty northerly winds and single-digit humidities will likely bring a brief period of critical fire weather conditions for portions of Los Angeles and Ventura counties on Wednesday night into early Thursday morning, helping to prime the already dry fuels across the region.
From Thursday night into Friday surface high pressure will build across the Great Basin, bringing the first widespread Santa Ana event of the season.
Winds are expected to increase sharply Thursday night across the mountains and valleys, descending into the coastal areas during the overnight hours. Offshore winds are expected to peak late Thursday night into Friday, tapering off by late Friday night.
Lowest humidities are expected to occur Friday afternoon into evening when widespread single digit humidities are forecasted.
During the peak period from late Thursday night through Friday, the Weather Service is forecasting northeast winds of 20-35 mph, with gusts ranging from 45-60 mph in passes and canyons throughout the region.
Relative humidity is expected to be at 10-20 percent Thursday night into Friday morning, dropping to 5-10 percent Friday afternoon and evening.