Minor to moderate thunderstorms were expected to affect most areas of Southern California over the weekend, including Long Beach, forecasters said today.

“Activity should peak this afternoon through Sunday morning,” the National Weather Service’s Los Angeles office tweeted Saturday. “Stay aware of your surroundings if outside, and seek shelter if you hear thunder.”

The NWS said a low pressure system moving over the region will create a “cool, showery, and unsettled weather pattern” into Monday.

Forecasters predicted 0.25 to 1 inch of rainfall over the mountains and interior valleys, with frequent lightning and isolated wind gusts up to 45 mph.

A 20% chance of thunderstorms is forecasted in Long Beach on Saturday afternoon, growing to a 30% chance Saturday night and a 40% chance Sunday, mostly before 11 a.m, according to the NWS.

The city will see a 20% chance of rain Sunday night and into Monday morning, mostly before 11 a.m., before the weather is expected to clear.