Southern California sweltered through its hottest day of the year Wednesday as temperatures climbed into the triple digits across the region and forecasters warned that dangerous heat will continue through Thursday.
“Temperatures will reach their peak this afternoon, where moderate heat risk will be present for many inland, locally major for far inland valleys and the lower deserts,” according to the National Weather Service.
“Even the mountains will be warm with highs in the 80s and 90s,” the weather service added.
An extreme heat warning took effect at 10 a.m. Tuesday for much of Los Angeles County and will remain in place through 8 p.m. Thursday.
The warning covers the valleys, mountains and inland portions of the coastal plain, where temperatures are expected to range from the 90s to as high as 110 degrees during the peak of the heat event Wednesday and Thursday.
A heat advisory will remain in effect through Thursday evening for coastal areas, including Los Angeles County beaches and the Palos Verdes Hills, where temperatures could still climb well into the 80s and 90s, forecasters said.
An extreme heat warning will also be in place for inland Orange County areas from 10 a.m. Wednesday to 8 p.m. Thursday, with a heat advisory in place during the same time frame for Orange County coastal areas.
Forecasters warned that lingering monsoonal moisture will boost humidity levels and make conditions feel even more uncomfortable. That moisture could also lead to rain, with forecasters saying there will be a 20% to 40% chance of showers or thunderstorms in the mountains and Antelope Valley.
A red flag warning of critical fire danger conditions will be in place from noon Wednesday through 9 a.m. Thursday for the Golden State (5) Freeway corridor in Los Angeles County, thanks to the combination of strong northwest to north winds, high heat and low relative humidity.
Overnight temperatures will offer little relief, with lows Wednesday night expected to remain in the lower 70s in many communities, increasing the risk of heat-related illness.
Temperatures are expected to gradually ease heading into the weekend as onshore flow strengthens and cloud cover increases, although conditions are expected to remain above normal through at least Friday, forecasters said.
Authorities urged residents to drink plenty of water, limit outdoor activities during the hottest parts of the day, seek air-conditioned shelter when possible and check on elderly relatives, neighbors and others vulnerable to heat illness.