Temperatures throughout San Diego County will warm slightly each day leading up to the arrival of a heat wave for Labor Day weekend, according to the National Weather Service.
The agency issued an excessive heat watch that will be in effect from Friday morning through Monday evening in the western valleys, the mountains and the deserts. An excessive heat watch will also be in effect from Saturday morning through Monday evening in coastal areas.
High pressure will strengthen over California throughout the week and begin ushering in the sweltering conditions on Friday, forecasters said. Monsoonal moisture is not expected to accompany the weekend heat, meaning it will not feel as muggy as recent heat waves.
Temperatures in the deserts could reach 119 on Sunday and 118 on Monday, while highs in the western valleys are expected to top out at 109 on Saturday, forecasters said.
High temperatures Wednesday are forecast to reach 76 degrees near the coast, 80 inland, 83 in the western valleys, 90 near the foothills, 94 in the mountains and 109 in the deserts.
