Strong thunderstorms swept across the Southland Thursday, prompting flash flood warnings, severe thunderstorm warnings and numerous flood advisories, while weather officials investigated a possible tornado in Orange County.
The National Weather Service said the morning storms brought heavy downpours and dangerous conditions, including a flash flood warning that remained in effect for eastern Los Angeles County into the early afternoon.
Forecasters said the most intense weather appeared to have passed by early Thursday afternoon, although scattered showers and isolated thunderstorms remained possible through the evening.
The National Weather Service’s San Diego office was also investigating a possible tornado at the San Clemente Golf Course. The report was received around noon Thursday, but officials were uncertain when the suspected damage occurred. Fox11 aired cell phone video showing extensive damage to numerous trees on the golf course. A weather service survey team was being sent to the golf course to determine whether a tornado had touched down.
Scattered showers and isolated thunderstorms remained possible through the afternoon and evening, although forecasters said they did not expect storms as widespread or intense as those that developed Thursday morning.
The storm moved into Los Angeles County on Wednesday, bringing periods of heavy rain and raising concerns about flooding along the Malibu coast and in the Santa Monica Mountains.
A flood watch remained in effect Thursday for Malibu, Malibu Bowl, Pacific Palisades, Topanga and portions of the eastern and western Santa Monica Mountains.
Forecasters warned that heavy rainfall could cause flooding in urban and poorly drained areas, including streets, creeks and rivers. Areas near steep hillsides and recent wildfire burn scars also faced potential runoff, mud and debris hazards.
Overall rainfall totals from the multiday storm were expected to average about 1.5 inches across much of Los Angeles County, with 2 to 3 inches possible in areas where terrain enhanced rainfall or thunderstorms produced concentrated downpours.
Along the coast, scattered showers and isolated thunderstorms were expected to continue affecting ocean waters into Thursday evening, potentially producing lightning, erratic wind gusts, rough seas and waterspouts.
A beach hazards statement remained in effect through late Thursday night for portions of the Los Angeles County coastline, where elevated surf and dangerous rip currents were expected. Minor beach erosion and tidal overflow were also possible in low-lying areas.
Los Angeles County health officials issued an ocean water quality rain advisory through at least 3 p.m. Saturday, warning residents to avoid contact with ocean water, particularly near storm drains, creeks and rivers that can carry bacteria and debris into the ocean.
Dry and warmer conditions are expected to return Friday and continue through the weekend, with a weak Santa Ana wind pattern developing as the storm moves out. Forecasters said offshore winds should remain mostly below advisory levels and be concentrated in mountain and some valley areas.
Temperatures are expected to rise to near or slightly above normal levels through the weekend and into next week.