Triple digits temperatures are expected again Friday in the San Diego County deserts, but temperatures elsewhere will be much cooler.
High pressure that has kept temperatures scorching all week will weaken substantially over the weekend, dropping highs in the deserts to the mid- 90s on Monday and highs in the western valleys to the high-70s, according to the National Weather Service.
A heat advisory in the western valleys has expired, but an excessive heat watch will also last until 9 p.m. today in the deserts.
High temperatures today are forecast to reach 78 degrees near the coast, 84 inland, 86 in the western valleys, 90 near the foothills, 91 in the mountains and 107 in the deserts.
Record thermometer readings for Thursday's date included 97 degrees in Escondido, exceeding the prior May 7 milestone of 94, set in 2004; 92 in Ramona, (90, 2007); 83 on Palomar Mountain (82, 1989); and 95 in Campo (92, 2001).
Good morning, #SoCal! ☀️ Highs today will be a few degrees cooler than yesterday for most locations, but hot weather will continue in the Inland Empire and the deserts. A cooling trend is in store for this weekend and next week! #cawx pic.twitter.com/HT5E6WvuYf
— NWS San Diego (@NWSSanDiego) May 8, 2020
In the arid, sun-baked Borrego area, the high of 106 tied the prior record, set in 1990.
Nighttime lows are expected to remain in the low- to mid-70s through Saturday in the county deserts, 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-related illness, and NWS officials 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.