A "cold and vigorous" storm system headed for the Southland today, threatening snowfall at unseasonably low levels, but the bulk of the rain was expected to remain off the coast.
As of this morning, today's and Thursday's rainfall was expected to be less intense than had been initially anticipated, when the storm appeared likely to sweep squarely over California's land mass, National Weather Service forecasters said. It was now expected to come largely in the form of showers, although there is a chance of a thunderstorm tonight, they said.
Along the coast, a "high rip current risk" persisted and was expected to last through Friday, according to the forecasters, who also warned of unusually high surf.
Gusty winds were also in the forecast, with the strongest expected Thursday afternoon, and freezing temperatures "are possible" in the Antelope Valley Thursday night and early Friday morning, according to an NWS advisory.
The storm, off the coast in Northern California's Eureka area early this morning as it moved southward, appeared to pose no great threat to communities below fire-denuded slopes – especially since catch basins largely have been cleaned out since the last storm in late February, NWS forecasters said.
But any thunderstorm that develops over burn areas and generates as much as a half-inch of rain in a period of about 20 minutes could alter the picture, they said.
With the bulk of the rainfall appearing to remain off the coast, between a quarter-inch and a half-inch of rain was expected in Southland coastal and valley areas – less in the mountains and foothills, said NWS meteorologist Dave Bruno.
In mountain areas above the 3,000-foot level, between two and four inches of snow are expected, he said.
"There's definitely a blob of rain working its way down the coast, but now it looks as if most of it will remain offshore," Bruno said. "It's mostly going to wet the fish."
There are two "wild cards," however, that could alter that forecast – if the storm begins moving closer to shore, and if thunderstorms develop, he said, adding that the greatest chance of thunderstorms will come between 7 tonight and 7 a.m. Thursday.
No alerts were issued for residents in communities below the site of the 250-square-mile Station Fire.
Along with the fact that the rainfall was not likely to be as intense as had been expected a few days ago, the system of 30 debris basins that forms a line of defense between mountains slopes ravaged by the Station Fire and thousands of homes below is said to be ready.
According to a Los Angeles County Department of Public Works schedule, 25 of the basins are to have been 100 percent cleaned out as of today.
The other five basins, the system's largest, have been excavated with a view to restoring 60 to 85 percent of their capacity by today, according to the department.
Smaller basins, which between November and February were considered most at risk of being overwhelmed, were totally cleared out earlier this month, the department reported. That includes Mullally Basin, near the high end of Ocean View Boulevard in the Paradise Valley neighborhood of La Canada Flintridge.
Temperature highs were expected to be in the mid 50s in the Antelope Valley and the low 60s in most other other Southland communities today and Thursday, rising several degrees Friday, when sunny weather is expected.