Temperatures in San Diego County will rise again Tuesday before peaking on Wednesday.
A high-pressure system building over the southwest will bring warmer temperatures each day until Thursday, according to the National Weather Service.
Highs in desert areas could reach 119 on Wednesday, then temperatures will drop significantly heading into the weekend, forecasters said. Temperatures in the inland valleys will reach the high 80s on Wednesday and the mercury could rise to 98 that day near the foothills.
The NWS issued an excessive heat warning that will be in effect from 11 a.m. to 8 p.m. Wednesday in the county deserts.
Nighttime temperatures could remain in the low 80s until Thursday in desert areas, meaning the minimal cooling at night could pose a health risk to those who don't have access to air conditioning because the body needs time to cool down from the day's heat, according to the NWS.
The combination of hot days and warm nights is expected to increase the threat of heat illness, and the NWS urged residents to drink plenty of fluids, stay out of the sun and check up on relatives and neighbors.
High temperatures Tuesday could reach 83 degrees near the coast and inland, 87 in the western valleys, 95 near the foothills, 98 in the mountains and 117 in the deserts.
