RIVERSIDE, Calif. -

A red flag warning signaling a heightened risk of wildfire will be in effect throughout Riverside County this weekend.

The red flag warning -- the most serious fire-related warning issued by the National Weather Service -- is scheduled from 2 a.m. Friday to 8 p.m. Sunday, according to the agency.

A red flag warning means that critical fire weather conditions are either occurring or will be occurring shortly. Those conditions include strong winds, low relative humidity and warm temperatures.

A moderate strength Santa Ana wind event this weekend will bring sustained winds of 15 to 25 miles per hour and gusts up to 60 mph, an NWS advisory said.

The lowest daytime humidity is expected to be around 5 percent, with poor overnight recovery. Temperatures are expected to be in the high 80s to low 90s in the Inland Empire, high 70s to high 80s in the mountains and mid- to high 90s in the Coachella Valley.