The Big Bake: Heat Wave Keeps Grip on Southland

(CNS) – A prolonged and prodigious heat wave will continue to bake the Southland Thursday — one day after record-setting temperatures were recorded in some areas and a state-wide Flex Alert was issued to minimize strain on the power grid.

More of the same searing conditions are in store through the Labor Day weekend, with excessive heat warnings in place through then.

"We are anticipating this extreme heat to be a length and duration the likes of which we haven’t experienced in some time," Gov. Gavin Newsom said Wednesday. "Yes, we’re used to record-breaking temperatures, maybe a day or two, more episodic, but this is an extended period."

The California Independent System Operator, which manages the power grid, has called for another Flex Alert on Thursday from 4 to 9 p.m. A Flex Alert had been in place on Wednesday as well, for the same hours.

In addition, the extreme heat and low humidity could create elevated fire weather conditions, NWS forecasters said. Wednesday, a major brush fire broke out in Castaic — consuming more than 4,600 acres, injuring several firefighters and forcing multiple evacuations and road closures.

The forecast has also prompted continued calls for residents to take precautions against heat stroke.

An excessive heat warning is in effect in parts of Riverside County until 8 p.m. Monday, with dangerously hot conditions expected with temperatures between 103 and 112 degrees in Riverside County valleys and the Inland Empire.

The Big Bake began on Monday but spiked even more Tuesday and Wednesday, with no signs of letting up any time soon.

"High pressure will persist over the area creating a prolonged period of very hot conditions with minimal coastal clouds," the NWS said.

"Triple digit heat is expected for many valley and mountain locations through early next week including coastal areas during the Sunday and Labor Day peak. This heat may be record breaking and will produce a very high risk of heat illness. Cooling trend by still warm to begin Tuesday or Wednesday."

Extreme heat is in the forecast for Riverside, Moreno Valley, Rancho Cucamonga and Corona.

Idyllwild reported a record high for Aug. 31 of 96, breaking the high of 94 recorded in 2017.

"Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors," the NWS urged. "Young children and pets should never be left unattended in vehicles under any circumstances."

Forecasters also urged residents to be aware of the signs of heat stroke and to take precautions.

"Take extra precautions if you work or spend time outside," according to the NWS. "When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location."

Overnight lows will not offer much relief either, staying in the 70s and even in the low 80s in some of the hotter areas.

Meanwhile, more Flex Alerts are anticipated over the weekend, particularly on Sunday and Monday, which are forecast to have the highest electricity demand.

"With excessive heat in the forecast across much of the state and Western U.S., the grid operator is expecting high electricity demand, primarily from air conditioning use, and is calling for voluntary conservation steps to help balance supply and demand," according to Cal-ISO.

During the alerts, residents are urged to take power-saving steps such as:

— setting thermostats to 78 degrees or higher;

— avoiding use of major appliances;

— turning off unnecessary lights; and

— avoid charging electric vehicles.

Residents are also advised to pre-cool their homes as much as possible, and close blinds and drapes to keep interiors cool.

Cooling centers for Riverside County can be found at http://www.capriverside.org/cool-centers.

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