With the strongest of the winds in the inland valleys and mountains of San Diego County on Monday night through Tuesday morning, the highest wind gusts of 102 mph were recorded in Sill Hill, near Julian. This is a typical wind-prone area in the mountains known for exceptionally high wind gusts, offshore and onshore.

Red flag warnings are in effect until Thursday for parts of Los Angeles, Ventura and San Diego because of low humidity and relentless Santa Ana winds.

Santa Ana winds will continue whipping through Southern California through Thursday, sparking fears that progress made fighting wildfires that have scorched over 40,000 acres and left 28 dead could be reversed and more blazes could break out.

Millions of California residents were placed under a red flag warning through Thursday amid threats of further fires with looming winds in the forecast, according to multiple reports.

San Diego County remains under the grip of another round of moderate to strong Santa Ana winds, paired with extremely dry air, elevating critical fire weather concerns.

Several counties in Southern California faced "critical" fire risks this week, according to an AccuWeather forecast.

According to AccuWeather, a storm sliding south along the California coast from Friday to Sunday could bring some much-needed rainfall.

"A Red Flag Warning means that critical fire weather conditions are either occurring now, or will shortly," the NWS said.

An uptick in Santa Ana winds Wednesday afternoon through Thursday, combined with critically dry vegetation and low humidity, will result in elevated to locally critical fire weather conditions in County through late Thursday.

Wildfires in San Diego have led to mandatory evacuations in the area on Tuesday. Officials tell FOX News that two wildfires are burning in San Diego County, with strong Santa Ana winds creating "dangerous fire conditions." RELATED: Why are winter wildfires happening in Southern California?

Wildfires in Southern California prompt evacuations and school closures as Santa Ana winds exacerbate conditions. Communities remain on high alert.- Watch Video on English Oneindia