The National Weather Service said an excessive heat warning goes into effect at 12 p.m. Friday, lasting through at least 9 p.m. Monday
A “long-duration” heat wave will sweep San Diego County this Friday -- through the weekend and beyond -- with the potential for near-record high temperatures in some parts of the region.
The National Weather Service calls this a “dangerous long-duration heat wave.” It’ll impact all of Southern California, spanning San Diego, Orange, Riverside and Imperial counties.
The NWS said the heat wave is concerning for two reasons: it’ll last five to six days and it’ll also be warm at night, offering little reprieve.
To that end, an excessive heat warning will go into effect at 12 p.m. Friday for San Diego County. That warning will last through at least 9 p.m. Monday (Aug. 17).
“This stretches through the entire weekend,” NBC 7 meteorologist Sheena Parveen explained. “Remember, you have to stay hydrated; drink plenty of water.”
Meanwhile, the agency that monitors California's electricity usage is bracing for the heat wave's potential impact on their system. The California Independent System Operator Corporation (ISO) issued a Flex Alert for Friday urging residents to conserve energy from 3 p.m. to 10 p.m. -- when overtaxing the system could lead to outages.
Parveen said the temps have been slowly rising all week but on Friday, the heat wave will be hard to ignore. NBC 7's First Alert Forecast showed the inland valleys hitting nearly 100 degrees Friday.
“We could be close to some record highs in the county,” she added.
And it’ll last a while.
"Our weather pattern will stay unseasonably hot through the weekend," Parveen said. "Next week we will still be unseasonably warm, so no big cool-down any time soon."
The NWS said it’ll be hottest in the deserts and Inland Empire, with temps from 98 to possibly 118 degrees (in the low SoCal deserts).
San Diego County valleys are expected to hit between 92 and 104 degrees.
The NWS said the temps will be 10 to 15 degrees above normal for this time of the year in areas away from the coast.
As always, heat like this can cause heat-related illness, so the NWS and Parveen say its best to stay out of the sun, drink plenty of fluids and never leave kids or pets unattended in parked cars.
Outdoor activities should be limited to early morning or evening, too.
Remember, San Diego County runs several Cool Zones, and these may be a good place to go for relief from the heat.