Overview

• National Weather Service extreme heat warnings and advisories begin Wednesday and run through the weekend for large parts of Southern California, with similar alerts across the broader Southwest.
• Forecasters expect peak temperatures Thursday and Friday, with widespread triple digits inland, warm overnight lows, and Death Valley near 120 degrees.
• Red flag warnings cover the Los Angeles and Ventura County mountains and foothills from Wednesday morning through Saturday night, with additional fire weather alerts in Santa Barbara and San Luis Obispo counties.
• Monsoonal moisture is forecast to raise humidity and bring chances of afternoon and evening thunderstorms from Friday into the weekend, increasing lightning ignition and localized flood risks, especially in the Sierra.
• California’s Office of Emergency Services has deployed extra firefighting assets to Los Angeles County, and Los Angeles is adding cooling centers as officials urge residents to hydrate, seek air conditioning, and check on vulnerable people.