Strong and dry Santa Ana winds are expected to pick up across Southern California today in a critical period for a region battling multiple wildfires.

A red flag warning denoting the high risk of wildfires was initially supposed to expire Friday evening but was pushed to Saturday evening for much of the region due to the dangerous conditions.

RELATED: Live coverage of multiple wildfires burning in Southern California right now

The winds were expected to gain strength today with 18 to 24 hours of strong winds including gusts of up to 75 mph in some areas, before the winds gradually weaken Friday through Saturday, according to the National Weather Service.

“This is a significant period,” the NWS said in a statement. “Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high-profile vehicles towing trailers.”

There is a chance that critical conditions will continue through the middle of next week, with a possible slight increase in winds Sunday through Tuesday and humidity between 6 to 12 percent in many areas, the NWS warned.

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People are urged to use extreme caution with fire ignition sources, with strong potential for fires to spark and spread rapidly.

Temperatures in Los Angeles County today are expected to hover in the 70s, with highs of 77 in Woodland Hills; 78 in Pasadena; 79 in Downtown L.A., San Gabriel, Burbank and at LAX; and 80 in Long Beach.

Orange County is expected to see sunny skies and strong winds with highs of 73 in Laguna Beach; 75 in San Clemente; 77 in Newport Beach and Yorba Linda; 79 in Fullerton and 80 in Irvine.

Temperatures will hover between 69 to 77 degrees in Riverside County and much of the Inland Empire.