Radar map of showers
Weather Service radar shows thunderstorms over San Diego County on Tuesday morning.

San Diego County residents woke up Tuesday to lightning, thunder and scattered showers that prompted the National Weather Service to issue a flash-flood warning for parts of East County.

“Scattered showers and isolated thunderstorms are moving slowly westward across portions of southern California,” the weather service said in a statement at 5:10 a.m. “The thunderstorms have mostly been in San Diego County and coastal waters.”

Accidents were reported on Interstate 15, and the Weather Service cautioned that roads would be slick during the morning commute.

The flash flood warning is in effect from 11 a.m. through the evening for the mountains and deserts.

“Isolated strong thunderstorms could generate rainfall rates of 1 to 2 inches per hour with flash flooding possible,” the weather service said.

Highs Tuesday are forecast to be 74 to 79 along the coast, 77 to 82 in the western valleys, 81 to 86 near the foothills, 81 to 89 in the mountains and around 102 in the deserts.

Chris Jennewein is founder and senior editor of Times of San Diego.