Punishing triple-digit heat continued to bear down on Southern California Saturday, with flash flood and thunderstorm warnings sprinkled into the mix in some areas.
A strong thunderstorm was expected to impact portions of central LA County through 3:30 p.m. Saturday, according to the National Weather Service. Doppler radar was tracking a strong thunderstorm eight miles northwest of Mount Wilson, moving west at 10 mph. The NWS reported wind gusts up to 50 mph and pea-size hail.
Gusty winds could knock down tree limbs and blow around unsecured objects. Minor damage to outdoor objects was possible.
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A flood advisory was issued through 5 p.m. for part of Orange County, with minor flooding possible in low-lying and poor drainage areas.
Skies were expected to clear up by midnight.
Meanwhile, excessive heat warnings were in effect until at least 8 p.m. Tuesday for the mountains and the Santa Clarita, San Fernando and San Gabriel valleys, along with the inland coastal area, including downtown LA.
The warning in the Antelope Valley will last until 9 p.m. Wednesday, with temperatures anticipated up to 113 degrees.
Saturday's highs topped out at 98 degrees in downtown LA, 104 in Pasadena, 106 in Van Nuys and 107 in Santa Clarita.
Oppressively high temperatures were forecast to continue through the holiday weekend, again raising fears of electrical shortages as residents crank up the air conditioning.
The California Independent System Operator -- which manages the state's power grid -- issued a first Flex Alert for the fourth consecutive day Saturday, urging residents to reduce electricity use from 4 to 9 p.m.
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.
The alerts have worked thus far, with the state avoiding involuntary power cutoffs.
According to Cal-ISO, electrical demand on Thursday topped out at 47,357 megawatts, the highest figure since September 2017. The agency projected that demand could exceed that number on Sunday, Monday and Tuesday, with Tuesday's forecast at 49,000 megawatts.
In Orange County, excessive heat warnings will also be in place through 8 p.m. Tuesday for coastal and inland areas and the Santa Ana Mountains and foothills. Forecasters said Orange County beaches will be in the 80s, with inland areas hitting the 90s, and possibly up to 105 farther from the coast in cities such as Anaheim, Garden Grove, Irvine and Fullerton.
The warnings were all originally expected to expire Monday night.
"A prolonged period of very hot conditions with minimal coastal clouds is expected as high pressure aloft remains anchored over the West,'' according to the National Weather Service. "Triple-digit heat will be common for many valley and mountain locations through early next week. Record-breaking heat will produce a very high risk of heat illness.''
"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.
Cooling centers for Los Angeles County can be found at ready.lacounty.gov/heat/. Cooling centers for the city of Los Angeles can be found at https://emergency.lacity.org/la-responds/beat-heat, or by calling 311.