The threat of wildfire will hang over large swaths of the Southland today because of the possibility of dry thunderstorms, which would send lightning bolts crashing down on bone-dry vegetation amid gusty winds, forecasters said.
A red flag warning denoting a high risk of wildfire will be in force from noon to 9 p.m. in the Antelope Valley and the Los Angeles and Ventura county portions of the San Gabriel Mountains, which includes the Angeles and Los Padres national forests.
"Scattered thunderstorm activity is expected from this afternoon through this evening," according to a National Weather Service advisory. "The storms are expected to produce little rainfall, resulting in dry lightning strikes."
In Altadena, forecasters predict a 20 percent chance of thunderstorms Thursday, with a high of 90 degrees. The chance for thunderstorms continues into Friday, when temperatures are predicted to go as high as 95 degrees.
Potential lightning and winds could gust at 50 miles per hour, to combine with high temperatures "and very dry fuels" to create "the risk of fire ignitions and rapid fire growth," the advisory said.
But any thunderstorm Thursday night will be wetter than Thursday afternoon's, reducing the risk of fire spread, according to NWS forecasters.
Monsoonal moisture will bring partly to mostly cloudy skies to the region Thursday, when a slight break is expected in the heat wave gripping the region.
Afternoon temperatures were expected to be a few degrees cooler than Wednesday, and the weather service this morning cancelled excessive heat warnings that had been scheduled to be in force until tonight.