Anza-Borrego State Park
A sign at the Anaz Borrego State Park near Borrego Springs. Courtesy University of California

Temperatures will begin warming Monday throughout San Diego County as another high-pressure system brings extreme heat to the deserts by midweek.

A high pressure system passing through Mexico will cause temperatures to warm through Wednesday, according to the National Weather Service office in San Diego.

Highs in desert areas could reach 114 on Tuesday and 117 on Wednesday, then temperatures will drop heading into the weekend, forecasters said. Temperatures in the inland valleys will reach the high 80s both days and the mercury could rise to 99 on Wednesday near the foothills.

The weather service issued an excessive heat warning that will be in effect from 11 a.m. to 8 p.m. Wednesday in the county deserts.

High temperatures Monday could reach 81 degrees near the coast and inland, 84 in the western valleys, 92 near the foothills, 94 in the mountains and 111 in the deserts.

— City News Service