A thunderstorm developed near Santa Monica Thursday morning without producing immediate signs of damage, but forecasters warned of high surf, some coastal flooding and the possibility of mud flows as the latest Pacific storm continued to drench the region.
But the downpours associated with Wednesday's storm are less likely.
"Another day, another round of rain and snow," said NBC4 forecaster Crystal Egger. "Once we get to the afternoon, that's when we get into more hit and miss activity. Some of us will be dry. Rainfall amounts are much lighter today."
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Doppler radar was tracking the thunderstorm off Santa Monica, which was moving east at around 30 miles per hour. Such thunderstorms can produce dime-size hail, winds exceeding 40 mph, and roadway flooding. Its impact on the Southland this morning was being tallied.
Thunderstorms struck Long Beach and other areas, bringing hail and heavy rains. Thursday's storm was expected to create drier conditions.
Scattered showers and isolated thunderstorms are possible aross the burn areas of Ventura and Los Angeles counties. Rain could fall at a rate of a half-inch to three quarters of an inch per hour. A flash flood watch was in effect until noon Thursday for the burn areas in the San Gabriel and Santa Clarita valleys, the San Gabriel Mountains and several areas of Ventura County.
The coastline, meanwhile, was being battered by what an NWS statement called "very large damaging surf."
A high surf warning will be in force in Los Angeles County until 4 a.m. Friday, and a coastal flood advisory is due to expire at noon today. NWS forecasters warned that the surf will build to between 10 and 14 feet, with sets of 16 feet expected this morning.
In Orange County, a high surf warning was in effect until 10 p.m. Friday, and a flash flood watch will be in effect until noon today.
The combination of high astronomical tides, onshore winds and very large surf will cause minor overflow of sea water into low-lying areas today, especially during the times of highest today," an NWS statement said.
The NWS blamed the high surf on a series of long-period westerly swells.
Three El Nino-caused weather systems hit Southern California this week, including one that slammed into the region late yesterday morning. Today's temperatures were expected to be like Wednesday's -- in the 50s and low 60s.
City News Service, Adrian Arambulo and Crystal Egger contributed to this report.