SAN DIEGO -- Temperatures are expected to soar well into the triple digits Monday in the San Diego County deserts before cooling off slightly through next weekend.
An excessive heat warning for desert areas is set to expire at 8 p.m. Monday, according to the National Weather Service.
Nighttime lows in those areas are not expected to drop below 77 degrees.
NWS officials urged residents in the deserts to drink plenty of fluids and check up on elderly relatives and neighbors, especially those without air conditioning.
The mercury is expected to reach 116 degrees Monday in the deserts, while highs will top out at 90 in the western valleys, 98 near the foothills, 87 in coastal areas and 99 in the county mountains, forecasters said.
The high pressure system is expected to weaken on Tuesday, dropping high temperatures by about two degrees throughout the county, according to the NWS.