The first major heat wave of the summer arrived in the Southland Saturday, with temperatures reaching triple digits in some areas and forecasters warning of “dangerously hot” conditions over the Fourth of July weekend.
An excessive heat warning was in effect through 8 p.m. Sunday in the Santa Clarita Valley, the Antelope Valley and the foothills. Those areas could see temperatures of 100 to 112 degrees, according to the National Weather Service, which warned of the potential for heat-related illnesses.
A less-severe heat advisory was in effect during the same hours in the Los Angeles County mountains.
The South Coast Air Quality Management District also issued an Ozone Advisory through Monday, warning that the excessive heat could increase the likelihood of poor air quality in many areas. Ozone exposure can be hazardous for children, older adults, and people with asthma or COPD. A map highlighting the air quality in various areas is available at aqmd.gov/aqimap.
The hot and dry conditions were also creating elevated wildfire risk.
“Drink plenty of fluids, stay out of the midday sun, and check up on relatives and neighbors,” the NWS advised. “Young children and pets should never be left unattended in vehicles under any circumstances.”
The heat is the result of a building high-pressure system, which will bake inland areas. Beaches are expected to be popular destinations for the weekend, with forecasters noting that “a persistent marine layer and onshore flow” will keep temperatures down in coastal areas.
Forecasters noted that in the hottest areas, overnight temperatures won’t offer much relief, falling only into the 70s to near-80 in some locations.
“While more sunshine will be prevalent and much warmer temperatures will develop away from the coast, the beaches will be mired in low clouds into the afternoon,” according to the NWS. “As a result, the warming trend will be moderated for the coastal areas.”
The high-pressure system is expected to dissipate beginning Monday, although temperatures should remain above normal for the Fourth of July holiday on Tuesday. More significant cooling is anticipated Wednesday and Thursday.
Meanwhile, the Los Angeles County Department of Public Health is reminding people to take precautions to avoid heat-related illness, especially among older adults, young children, outdoor workers, athletes, and people with chronic medical conditions who are especially sensitive to the negative health impacts of extreme heat.