Two storms are lined up to arrive from opposite directions in Southern California this week, and people who live in recently burned hills and mountains were warned of possible debris flows and flash floods, the National Weather Service said Sunday.
Thunderstorms left over from now-Tropical Storm Rosa, were expected to produce clouds over Los Angeles but there was only a chance they would bring measurable rain to the area Monday night, NWS Meteorologist Keily Delerme said.
She noted there was rain in eastern San Diego County Sunday night.
A low pressure system moving in from the Pacific Ocean was expected to deliver 1/4 to one inch of rain Tuesday through Wednesday in the Los Angeles area, and possibly more rain in the mountains if thunderstorms develop, Delerme said.
The greatest impact from the Pacific system could be felt in areas where wildfires burned over the summer, she said. Mudslides or debris flows were possible.
And the unsettled weather has brought a High Surf Advisory to Los Angeles area beaches through Tuesday morning with sets of six to 10 feet possible.
Orange County Fire Authority Capt. Steve Concialdi said their agency was preparing for heavy rain in Upper Trabuco and Holy Jim canyons, which burned two months ago. Contingency plans for debris flow or mudslides in the steep canyons east of Irvine are drawn up, and heavy equipment operators and hand crews are available if needed.
Concialdi said all fire stations in Orange County have sandbags, which are available to residents. But not all have sand to put in them.
The possible storms would be the first rain event of the season, Delerme said. But they won’t bring a blast of cold air. Temperatures were expected to drop into the 70s Tuesday and Wednesday inland and 60s along the coast with a warmup back into the 80s by Friday inland and 70s along the coast and temperatures should continue to be warm next weekend.
It is too early to tell whether it will be a wet winter, she said. Forecasters are on the watch for a weak El Nino which could increase or decrease the chance of rain.