The Southland’s fiercest heat wave this year entered its second week Monday, threatening “excessive heat” and elevated fire danger through at least the middle of next week, a National Weather Service meteorologist said.
The high heat can be attributed to a strong ridge of high pressure anchored over Nevada, said NWS meteorologist Dave Bruno.
An excessive heat warning, which has been extended since it was first issued last week, will be in force until 9 p.m. Thursday in the San Fernando, Santa Clarita, San Gabriel and Antelope valleys, as well as the San Gabriel and Santa Monica mountains. The weather service said conditions in those areas would be “dangerously hot.” In inland Orange County and the Santa ana Mountains, the warning will expire at 10 p.m. Thursday.
A less serious heat advisory will be in effect until 9 p.m. Thursday in the L.A. coastal zone — beach cities, metropolitan Los Angeles, Downtown L.A. and the Hollywood Hills.
“Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities,” warned the NWS. “Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening.”An excessive heat warning will remain in effect in inland Orange County and the Santa Ana mountains until 10 p.m. Thursday.
Along with torrid weather, the NWS forecast “elevated fire danger.” The NWS has not issued any red flag warnings because winds have not been strong enough to meet NWS criteria, Bruno said.
But “it’s not going to take much” to set a wildfire in addition to those already burning, he said, and red flag warnings may yet be issued, particularly in the event of more dry lightning.
Also confronting Southland residents is foul air as a result of “the current heat wave, along with stagnant weather and ongoing wildfires,” said the South Coast Air Quality Management District.
Smoke advisories were issued as a result of the Ranch2 Fire north of Azusa and Duarte, and the Lake Fire northeast of Castaic.
The AQMD said in a statement that it urges people “who smell smoke or see ash to limit exposure by remaining indoors with windows and doors closed or to seek alternate shelter and avoid vigorous physical activity.”
The heat wave, which Bruno said is the fourth this summer, is the longest so far, he said, adding that Tuesday’s temperatures should be as high as Saturday’s. Some cooling will begin Thursday, but temperatures will not revert to normal before the middle of next week, he said.
The heat will continue to strain the state’s electricity grid. Managers of California’s power grid issued a statewide Flex Alert on Sunday, calling for voluntary electricity conservation through Wednesday and warning of rolling blackouts. The Flex Alerts will be in effect from 3-10 p.m. each day.
The California Independent System Operator urged consumers to help by shifting energy use to morning and nighttime hours and conserving as much energy as possible during the late afternoon and evening hours.
Off the coast, a small craft advisory issued because of an expectation of hazardous conditions will be in force from 3 p.m. Monday through 3 p.m. Tuesday and a gale watch will be in effect from Tuesday afternoon through late Wednesday night amid winds of 20-30 knots, gusting to 35 knots.
The NWS reported partly cloudy skies near the coast Monday but bright sunshine at interior locations, along with highs of 85 at LAX and Avalon; 91 in Long Beach and on Mount Wilson; 96 in Downtown L.A.; 97 in San Gabriel; 99 in Pasadena and Burbank; 106 in Woodland Hills and Saugus; and 112 in Palmdale and Lancaster. Some communities will remain in triple-digit territory through at lease Sunday.
Sunny skies were forecast in Orange County, along with highs of 79 in Newport Beach, Laguna Beach and San Clemente; 89 on Santiago Peak; 92 in Irvine and on Santiago Peak; 93 in Fullerton and at Fremont Canyon; and 95 in Anaheim, Mission Viejo and at Trabuco Canyon. Some areas will remain in the 90s through at least Sunday.