Sunrise in Rancho Bernardo
Sunrise in Rancho Bernardo on Wednesday. Courtesy National Weather Service

Temperatures will be unseasonably warm throughout San Diego County on Thursday and reach well into the triple digits in the deserts.

The National Weather Service said that west of the deserts, it will be slightly cooler than Wednesday, but still warm.

A cooling trend is beginning and will continue throughout the region until early next week, forecasters said.

A heat advisory is in effect until 9 p.m. Friday in the western valleys and an excessive heat watch will also last until 9 p.m. Friday in the deserts.

Temperature records for May 6 were set in Borrego Springs and tied in Campo on Wednesday, during what was expected to be the hottest day of the week.

The 109-degree high in Borrego Springs broke the previous record for that date of 105, set in 1989, and the mercury reached 95 in Campo, tying the record set in 1989.

High temperatures Thursday are forecast to reach 80 degrees near the coast, 87 inland, 93 in the western valleys, 93 in the mountains and 110 in the deserts.

Nighttime lows are expected to remain in the low- to mid-70s through Saturday in the deserts. 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 weather service.

The combination of hot days and warm nights is expected to increase the threat of heat-related illness, and meteorologists 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 weather service.

— City News Service

Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.