The mercury could climb into the triple digits Thursday in the San Diego County mountains and foothills as a stretch of scorching heat begins in southern California.
A ridge of high pressure will continue building over the southwestern United States through Monday, ushering in the scorching heat, according to the National Weather Service.
The NWS issued an excessive heat warning that will be in effect from noon Friday to 9 p.m. Monday in the county valleys, mountains and deserts.
The NWS urged residents to drink plenty of fluids, stay out of the sun and check up on relatives and neighbors. Also, young children 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.
Highs in the county deserts could climb to 118 on Friday, then 119 from Sunday through Wednesday, according to the NWS. The mercury in the western valleys is forecast to top out at 95 on Friday, while highs near the foothills could hit 102 on Friday and 101 on Saturday.
High temperatures today are forecast to reach 82 degrees near the coast, 90 inland, 93 in the western valleys, 99 near the foothills, 100 in the mountains and 117 in the deserts.
