Rain, thunderstorms arrive as remnants of Tropical Storm Mario reach Southern California

Lightning strikes and brief, heavy downpours spread across Southern California overnight, with the risk of showers and potential flooding continuing through the day Thursday.

“A lot of this is just energy being pushed in from a tropical storm. Tropical Storm Mario is bringing remnants up toward Southern California,” KTLA Meteorologist Henry DiCarlo said Thursday morning. “Just about all of Southern California is at risk of some rain this morning, and we’ll see that chance of rain increasing with more thunderstorms this afternoon.”

Afternoon temperatures will be cooler through Friday, but it will still be warm and muggy as the increased moisture raises humidity levels, according to the National Weather Service (NWS).

Rain and thunderstorm chances are expected to continue into at least Friday morning.

Around 4 a.m. Thursday, KTLA’s Live Max Doppler showed a powerful cell over the Coachella Valley. “So, I-10 travel through Palm Springs and down into Blythe; there’s a lot of heavy thunderstorms,” Henry said.

The NWS has issued flood watches through late Thursday night for portions of Los Angeles, Ventura, Riverside and San Bernardino counties.

Officials shared the following recommendations during this thunderstorm period:

• This is a rapidly evolving situation with a range of outcomes: Stay tuned to the latest forecasts and advice from emergency officials.
• If you see lightning, hear thunder, or experience rapidly increasing winds: Seek shelter immediately.
• If you come to a flooded road: Seek shelter immediately.
• Plan for extra travel time: The Thursday and Friday commutes are expected to be the most affected.

A slight chance of showers remains in the forecast through the weekend as additional moisture from the south arrives.

“Warm and muggy. That’s the forecast through the weekend,” Henry said.