Red flag fire danger warning
A red flag fire danger warning outside a fire station in Valley Center. Courtesy OnScene.TV

The National Weather Service issued a red flag fire warning beginning on noon Thursday and continuing until 6 p.m. Friday for San Diego’s western valleys and mountains.

Santa Ana winds are forecast to grow in strength to 20 to 30 mph on Thursday and gust as high as as 50 mph overnight and into Friday morning.

“Across San Diego County, the stronger east winds are not expected until later Thursday and Thursday night into Friday, with critical fire weather conditions in the mountains and coastal foothills,” the weather service said.

Daytime humidity will fall to the 5-to-10% range on Thursday and drop further to around 5% on Friday.

“Use extreme caution with anything that could produce a spark,” the weather service warned.

Low humidity will continue into Saturday, but winds will be much weaker by then, according to the weather service.

Chris Jennewein is founder and senior editor of Times of San Diego.