'Instability' over Southern California driving chance for afternoon thunderstorms, showers

SIGNAL HILL, CALIF. - OCT. 4, 2021. Lightning flares from the clouds above the South Bay as a storm moves across the Los Angeles Basin on Monday, Oct. 4, 2021. (Luis Sinco / Los Angeles Times)
Lightning flares from the clouds above the South Bay in 2021. Lightning and rain are possible Monday in Southern California, meteorologists say. (Luis Sinco)

An unsettled atmosphere over Southern California could drive isolated storms across the region Monday afternoon, with an increased chance for strong thunderstorms.

If conditions allow, the thunderstorms could bring gusty winds, brief heavy showers, dry lightning and small hail Monday afternoon and evening over a large swath of southwest California as a low pressure system moves in from the east. Such storms are most likely to form over the mountains and foothills, according to the National Weather Service.

“We have a low pressure system that’s kind of sitting out over Arizona right now," said Kristan Lund, a National Weather Service meteorologist in Oxnard. "This will drift a little bit westward and it will bring some colder temperatures aloft ... and instability.”

That system is expected to clash with warmer temperatures on the ground — as much of Los Angeles County is forecast to reach into the 70s and 80s Monday — and with offshore winds, said Casey Oswant, a National Weather Service meteorologist in San Diego.

"There’s a lot of energy wrapping around that low pressure [system], and as that gets into our area this afternoon, we are expecting additional rounds of showers and thunderstorms," Oswant said.

Read more: This popular SoCal hiking spot is bursting with wildflowers — and bighorn sheep

While dry lightning always brings a fire threat and heavy rain can cause localized flooding, weather officials said those will remain relatively minor concerns Monday.

The low pressure system is expected to linger in the area Tuesday, with a chance for thunderstorms persisting, though that possibility will be even more isolated than Monday, Oswant said.

After Tuesday, meteorologists expect the region will remain dry through the weekend, when there's a chance for further precipitation — though that system is still developing and could change course in the coming days.

Sign up for Essential California for news, features and recommendations from the L.A. Times and beyond in your inbox six days a week.

This story originally appeared in Los Angeles Times.