A heat wave that began on Tuesday will intensify today and last through Thanksgiving with temperatures rising into the 80s at the coast and into the 90s across inland valleys and foothills. The National Weather Service says the hot weather will peak today with temperatures reaching 88 in San Diego — about 20 degrees above average — and the low 90s in Poway and 92 in Escondido. A dome of high pressure is preventing cool, moist air from flowing into Southern California — a pattern that’s not unusual in late autumn.