Temperatures could soar into the triple digits in most of San Diego County on Friday as a brutal stretch of heat begins, bringing an elevated risk of wildfires this weekend in the mountains and the western valleys, according to the National Weather Service.
The predicted hot spell and accompanying low humidity and gusty winds out of the east prompted the National Weather Service to issue a "red flag" wildfire warning for the local inland valleys and mountains, effective from 10 a.m. Saturday to 6 p.m. Sunday. The alert signifies a likelihood of critical combustion hazards that can lead to "extreme fire behavior."
High pressure will strengthen over the West Coast throughout Labor Day weekend, ushering in the sweltering conditions, forecasters said. The heat, low relative humidity and gust winds out of the east will also elevate fire weather conditions in the mountains and the western valleys on Saturday and Sunday.
Humidity will drop to the 15-20% range on Saturday and Sunday with poor overnight recovery, forecasters said. Winds out of the east are expected to reach speeds between 15-25 mph, with gusts potentially reaching 30- 40 mph in the southern parts of the county.
An excessive heat warning will be in effect in the western valleys, the mountains and the deserts from 10 a.m. Friday through 8 p.m. Monday. Another excessive heat warning for coastal areas will run from 10 a.m. Saturday through 8 p.m. Monday.
The California Independent System Operator (ISO) has also issued a statewide Flex Alert, a call for voluntary electricity conservation from 3 p.m. to 9 p.m. beginning Saturday and extending through Monday. The ISO predicts higher than usual electricity demand, mostly from air conditioning use, over the sweltering Labor Day weekend.
A fire weather watch was also issued from late Saturday morning through Sunday afternoon in the mountains and the western valleys.
The fire weather watch comes with a warning that any fires that develop will likely spread rapidly and outdoor burning is not recommended.
High temperatures Friday are forecast to reach 81 degrees near the coast, 91 inland, 95 in the western valleys, 104 near the foothills, 102 in the mountains and 117 in the deserts.
The NWS urged residents to drink plenty of fluids, stay out of the sun and check on relatives and neighbors. Also, children, seniors and pets should be never be left unattended in a vehicle, with car interiors able to "reach lethal temperatures in a matter of minutes," according to the NWS.
The mercury in the deserts is expected to reach 119 on Sunday and 122 on Monday, forecasters said. Highs in the western valleys could soar to 116 on Saturday and 114 on Sunday, while high temperatures near the foothills will remain in the triple digits through Monday.
To help the public beat the heat, the county is offering nine cooling centers in Alpine, Borrego Springs, Fallbrook, Lakeside, Potrero, Ramona, Santa Ysabel, Spring Valley and Valley Center. Due to the coronavirus, mandatory mask-wearing and social-distancing protocols are enforced in the facilities.
A full list of the cooling center locations can be found here. All locations will be open from noon to 5 p.m. throughout Labor Day weekend.
