Mostly cloudy conditions with a chance of showers and thunderstorms were forecast for the mountains, according to the National Weather Service. Meteorologists said there would be a 50 percent chance of measurable precipitation.
Forecasters predicted a 40 percent chance of measurable precipitation in the deserts and valleys, and a 30 percent chance along the coast.
A slight chance of rain throughout the county will carry over into tonight.
"Abundant moisture flowing around an area of high pressure will bring increased clouds today with a good chance of showers and thunderstorms, especially for the mountains and deserts,'' according to the weather service. "A few thunderstorms are possible over the mountains and deserts Wednesday afternoon as well.''
Forecasters said building high pressure would usher in warmer weather Thursday through Saturday that could potentially get close to breaking heat records.