It’s time to break out the fans and frozen treats as a midweek hot spell is heading to Southern California with temperatures up to 10 degrees above normal expected across the region on Wednesday and Thursday.
The worst of the L.A. County heat is forecast for the San Fernando, Antelope and Santa Clarita valleys, where temperatures are expected to sit in the 90s and potentially push into the triple digits, according to the National Weather Service.
People living in downtown and East Los Angeles can expect to see highs in the 80s to around 90, while temperatures will remain in the 70s along the coast.
“Big changes coming tomorrow [Tuesday] and the remainder of the week as high pressure over Arizona expands west into Southern California,” stated the weather service in its Monday night Los Angeles forecast. Weaker onshore winds and sinking air from a strengthening high-pressure system “will squash the marine layer to under 1000 feet by Wednesday and bring significant warming to inland areas and minor warming to coastal areas.”
The weather will be even more blistering in the Inland Empire, where a heat advisory will be in effect for wide swaths of San Bernardino and Riverside counties from 10 a.m. Wednesday to 8 p.m. Thursday, according to the weather service. The advisory applies to the cities of Corona, Moreno Valley, Ontario, Rancho Cucamonga, Riverside, San Bernardino and Fontana, where temperatures are expected to reach 97 to 104 degrees.
A heat advisory is in effect during the same timeframe in inland areas of San Diego County, including the communities of San Marcos, El Cajon, La Mesa, Escondido, Poway and Santee.
Residents living in these areas are advised to drink plenty of fluids, stay in air-conditioned rooms, stay out of the sun and check up on relatives and neighbors, according to the weather service.
The weather in Los Angeles is largely expected to sit below the heat advisory criteria, in part due to relatively cool overnight temperatures in the low to mid 60s, which will provide several hours of relief. Nevertheless, Angelenos are advised to avoid strenuous outdoor exercise and be aware of the dangers of heat-related illnesses this week.
The heat wave will begin to break on Friday as the high-pressure system weakens, bringing the return of onshore ocean breezes and cooler temperatures. More widespread relief is forecast for the weekend, when temperatures are expected to return to seasonal norms.
This week’s hot spell is expected to bring moderate fire weather. Forecasters predict a 20% chance of a red flag warning in interior valleys, mountains, and deserts.
More dangerous fire weather could be in the works next week as current models show the possibility of an even hotter heat wave coinciding with gusty onshore winds, according to the weather service.
