SAN DIEGO -- Thunderstorms will be possible again Wednesday throughout San Diego County in the midst of a heat wave.
Coastal areas, the inland valleys, the deserts and the mountains will all have a chance of thunderstorms Wednesday afternoon, according to the National Weather Service.
Mountain areas could also see thunderstorm activity Wednesday morning, NWS meteorologist Greg Martin said.
A high pressure system hanging over the Four Corners region is causing our heat wave while monsoonal moisture from Mexico is generating precipitation. Some light rain could accompany thunderstorms Wednesday before heavier showers are expected on Thursday, Martin said.
A chance of thunderstorms will continue through Friday evening in the mountains and through Thursday evening in the deserts, while the thunderstorm activity is expected to clear out of coastal and inland valley areas by Wednesday evening.
The chance of measurable precipitation has been set at 20 percent Wednesday for the inland valleys, coastal areas and the deserts, according to the NWS. There is a 50 percent chance Wednesday in the mountains.
High temperatures Wednesday are expected to reach 89 near the coast and inland, 93 in the western valleys, 98 near the foothills, 96 in the mountains and 111 in the deserts.
The heat wave is expected to peak on Saturday, when temperatures in the deserts could reach 116, forecasters said.