A monsoonal system from northern Mexico and Arizona will sweep hot, humid weather and a chance of thunderstorms into Southern California early Monday morning that will last through most the week.
The National Weather Service said coastal areas in L.A. and Orange counties could begin seeing showers as early as Monday morning.
"Late tonight and tomorrow there's a little disturbance in the atmosphere that's forecast by our computer models to move north across Southern California," said NWS spokesman Rich Thompson. "And that's actually going to bring the possibility of showers and thunderstorms to the coastal and coastal valley areas."
Beach-goers who see a storm developing should get out of the water and off the beach, he said.
Thompson said any thunderstorms that develop Monday would likely be on the dry side, but gusty winds and little rain could spark wildfires during an already explosive fire season.
"That would mean the possibility of dry lightning strikes which could start fires," Thompson said. "And the possibility of getting some really gusty and erratic winds from thunderstorms, which — if a fire does start — could spread the fire pretty quickly."
Storms from Tuesday on would likely be concentrated in mountainous and desert areas of Southern California, he said.
"If you're in the mountains — say you're hiking this week or you're at the beach tomorrow — and you see any indication of a thunderstorm developing, just take the proper precautions," like getting indoors and away from tall objects, Thompson said.