A long and grueling heat wave, the second of the summer, is in store for San Diego County this week as temperatures climb to triple digits in some areas, prompting an excessive heat warning through the weekend.
Day by day, temperatures will rise until they reach their peak this weekend, according to forecasters. The deserts will see the most dangerous triple-digit temperatures. The heat warning will go into effect for the mountains and deserts at 10 a.m. Tuesday and was extended until 8 p.m. Monday.
Temperatures will continue to soar well into the triple digits in the deserts this week and into next weekend, with more moderate temperatures in the coastal and valley areas.
Get top local stories in San Diego delivered to you every morning. >Sign up for NBC San Diego's News Headlines newsletter.
Monday's high in Borrego Springs was forecast at 109 degrees, and was expected to climb steadily throughout the week, reaching 117 by next Sunday, according to the National Weather Service.
Not only will daytime temperatures be very hot, but overnight lows will be elevated, especially in the low deserts, according to the NWS.
Local
Officials from Cleveland National Forest announced that San Diego River Gorge, Cedar Creek Falls, Three Sisters Falls and Eagle Peak trails will be closed starting Monday due to excessive heat.
The NWS advises people to drink plenty of fluids, stay out of the midday sun, and check up on relatives and neighbors during extreme heart events.
"Young children and pets should never be left unattended in vehicles under any circumstances," the agency cautioned.
The extreme heat may also prompt fire danger, although no Santa Ana winds are in the forecast to increase those chances, according to NBC 7 Meteorologist Sheena Parveen.
Highs will climb into the 90s in the mountain and valley areas this week, but will remain comfortable nearer the coast.