RIVERSIDE (CNS) - The mercury is expected to jump into the triple digits today in parts of the Riverside metropolitan area as temperatures begin to spike throughout Riverside County heading into the weekend.High pressure will build throughout the week over the southwestern United States, with temperatures expected to peak on Friday, according to the National Weather Service.The agency issued a heat advisory that will be in effect from 11 a.m. Thursday to 9 p.m. Saturday in the Riverside metropolitan area and the Riverside County mountains.An excessive heat warning will also be in effect from 11 a.m. Thursday through 9 p.m. Saturday in the Coachella Valley and the San Gorgonio Pass near Banning.Highs in the Coachella Valley are expected to reach 120 on Friday and might even
