The National Weather Service in San Diego has issued a Heat Advisory in effect from 10 AM Saturday to 8 PM Sunday across Orange County Inland Areas and the San Bernardino and Riverside County Valleys due to a significant rise in temperature as a high-pressure system builds over the region. The same advisory applies from 10 AM to 8 PM PDT Saturday for the mountains and valleys of Riverside, San Bernardino, and San Diego counties according to the Area Forecast Discussion of NWS San Diego.
In the high deserts, residents can expect an Excessive Heat Watch starting Saturday morning and extending through Sunday evening, while the lower deserts, including the Coachella Valley and San Diego County Deserts, brace for an Excessive Heat Watch that is in effect from Saturday morning through Thursday evening, signaling prolonged days of extreme heat where temperatures will soar between 110-116 degrees. San Gorgonio Pass near Banning also falls under this Excessive Heat Watch, as per the National Weather Service.
The incoming high pressure is expected to bring more than just heat. By Sunday, a surge of monsoon moisture is anticipated to raise humidity levels and introduce a chance for showers and thunderstorms, as noted by the NWS San Diego's Area Forecast Discussion.
