As the summer sun asserts its presence in San Diego, an Excessive Heat Watch has been declared for the upcoming Sunday and Monday, heralding temperatures that soar into the unforgiving mid-100s, according to the latest National Weather Service report. Residents of the Coachella Valley and San Diego County Deserts, as well as those traversing the San Gorgonio Pass near Banning, are advised to prepare for intense heat that could well persist into the following week.