A building upper-level ridge in the Southwest will lead to a warming trend later this week and into the weekend, according to the National Weather Service office in San Diego.
High temperatures Thursday are expected to reach 74 near the coast, 77 inland, 80 in the western valleys, 89 near the foothills, 94 in the mountains and 108 in the deserts.
Highs this weekend will be as much as 8 to 12 degrees above average for the inland valleys onto the lower coastal mountain slopes as well as the deserts.
Nights will be warmer over the weekend into early next week for the lower deserts and foothills with a shallow increase in lower level moisture Saturday.
Mid-level monsoonal flow will increase from Sunday into early next week, NWS said. The marine layer will keep coastal areas cooler with areas of night and morning low clouds spreading into portions of the valleys late at night, but less extensive.