San Diego County to see heat wave, chance of thunderstorms by week’s end

San Diego County will start the week under cooler skies and widespread coastal clouds, but a shift in weather patterns will bring hotter, drier conditions by midweek, according to the National Weather Service.

High pressure building over the Southwest will compress the marine layer, leading to less cloud cover and a steady warming trend, the NWS said.

High temperatures Monday are expected to reach 69 to 74 near the coast, 75 to 79 inland, 78 to 82 in the western valleys, 85 to 90 near the foothills, 84 to 92 in the mountains and 103 to 107 in the deserts.

Temperatures will return to seasonal averages by Wednesday before climbing well above normal Thursday through Saturday, with inland valleys expected to reach the 90s and coastal highs in the 70s to low 80s.

The hottest days are forecast for Thursday through Saturday, when temperatures in the deserts could soar past 110 degrees.

At the same time, monsoonal moisture will begin streaming into the region, raising the chance of showers and thunderstorms, mainly over the mountains and deserts.

Storm chances will be highest Friday and Saturday, possibly extending into the evenings, meteorologists said.