The upper ridge of high pressure that generated a heat wave starting Thursday will weaken early this week, which, together with the return of an onshore flow, will usher in a cooling trend across the Southland, forecasters said Monday.
But the humidity will continue to make the weather feel uncomfortable, said National Weather Service meteorologist Curt Kaplan. At the same time, monsoonal flow may bring showers and thunderstorms to mountain and desert areas Monday, according to an NWS statement, which added that, after a brief cooling trend midweek, conditions will warm up once again by next weekend.
No heat advisories were in effect Monday morning for the first time in days, and Kaplan said the same would be the case Tuesday.
However, the Los Angeles County Department of Public Health warned that air quality would be unhealthy Monday for all individuals in the San Gabriel Mountains and Santa Clarita Valley, and for people with heart disease or respiratory conditions in the eastern and western San Gabriel Valley and west San Fernando Valley, who are advised to minimize outdoor activities.
Schools with children who have sensitive conditions, including heart disease, asthma and other chronic respiratory diseases, should not participate in outdoor physical activity and should stay indoors as much as possible, according to Dr. Jeffrey Gunzenhauser, the county’s interim health officer.
In the San Gabriel Mountains and the Antelope Valley, there’s “a pretty good chance” of thunderstorms Monday afternoon, Kaplan said.
Also expected Monday is higher surf, strong rip currents and the threat of sneaker waves that can sweep beachgoers off rocks and jetties as a result of a moderately long southerly swell that’s been developing with Hurricane Eugene off the Baja California coast, according to an NWS statement. The surf will be even higher Tuesday morning through Wednesday evening along south-facing beaches of Ventura and Los Angeles counties, including Santa Catalina Island, according to the weather service.
Surf of between 5 and 8 feet is expected in Los Angeles County Tuesday morning through Wednesday evening, NWS forecasters said. A high surf advisory will be in effect from 6 a.m. Tuesday to 10 p.m. Wednesday, denoting dangerous rip currents and large waves. Forecasters advised beachgoers to swim near lifeguards and, if caught in a rip current, to remain parallel to shore until able to break free.
“There is an increased risk for ocean drowning, especially with more people seeking relief from the hot inland temperatures. Rip currents can pull swimmers and surfers out to sea. Large breaking waves can wash people off beaches and rocks and capsize small boats near shore,” the NWS statement said.
The NWS forecast partly cloudy skies in L.A. County Monday and highs running a little above normal at 80 at LAX and in Avalon; 86 in Long Beach; 88 on Mount Wilson; 89 in downtown L.A.; 90 in San Gabriel and Burbank; 91 in Pasadena; 94 in Saugus; 96 in Woodland Hills; and 100 in Palmdale and Lancaster. Temperatures will be similar throughout the week.
Sunny skies were forecast in Orange County, along with highs of 72 in Laguna Beach; 73 in San Clemente; 76 in Newport Beach; 89 in Irvine and Mission Viejo; 90 in Fullerton and Anaheim; and 92 in Yorba Linda.