A heat advisory for San Diego County mountains and valleys and an extreme heat warning for the deserts will expire at 8 p.m. Monday, with cooler temperatures on the way later this week.
High pressure over the southwest will continue to dominate the weather through Tuesday, then weaken after that, according to the National Weather Service.
Highs along the coast will be in the mid-80s through mid-week, then dip to the upper 70s to low 80s. In the inland valleys, the forecast calls for highs in the 80s. The mountains will begin the week in the upper 80s, before tapering off to the upper 70s…