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.
San Diego County deserts can expect temperatures in the low 100s at the beginning of the week, cooling to the upper 90s through the weekend.
Thunderstorm chances continue each afternoon and evening in the mountains and deserts through Wednesday, with the best chances Monday and Tuesday, forecasters said.
Wednesday through next weekend will see more pronounced cooling, with daytime highs as much as 10 degrees below normal in some inland areas by Thursday. Night and morning low clouds and fog could spread inland.
Astronomical high tides are expected to exceed 7 feet Monday through Wednesday between 8-9:30 p.m. Surf is not expected to play a large role in elevating the tides further, with a surf forecast of only 2-3 feet.
"Tides exceeding 7 feet can result in minor tidal overflow into low- lying areas along the beach, including beach parking lots," the NWS said.
A coastal flood advisory will be in effect at county beaches from 6 p.m. Monday until 11 p.m. Wednesday.
