Rain Expected to Make a Brief Reappearance

A complex storm system was expected to roll into Southern California before dawn today, bringing sustained light rain in the morning and occasionally potent thunderstorms in the afternoon that could trigger renewed mudslides.

Forecasters say the low-pressure front at the heart of the storm is relatively weak, but it is trailed by cold, unstable air that may generate some nasty isolated downpours, complete with lightning, hail and gusty winds.

Generally, about a quarter- to a half-inch of rain is expected today in the coastal areas of Orange County and up to an inch in the local mountains.

A few showers could linger into Saturday morning, but skies should clear by Saturday afternoon, according to meteorologist John Sherwin, who works for WeatherData, a firm that provides forecasts for The Times.

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The weather for the rest of the weekend should be gorgeous, he said, with a return of sparkling skies, gentle offshore winds and temperatures peaking near 80 degrees.

The sunny weather is expected to continue into next week, but forecasters caution that El Nino is still alive and well off the coast of South America.

Thanks largely to the continuing oceanographic and meteorological phenomenon, rainfall totals for March and April are expected to be above normal. However, Sherwin said any upcoming storms should be individual affairs, like today’s, rather than elements of a protracted series, like the ones last month that caused so much damage throughout the state.

The northern Pacific storm due in early today was still hovering off the Southern California coast Thursday afternoon, spinning off diaphanous cobwebs of high clouds that filtered the sunshine and limited high temperatures in most areas to the upper 70s--about 10 degrees cooler than Wednesday’s top readings.

Sherwin said the rain was expected to fall on the western outskirts of Los Angeles shortly after midnight, spreading inland and south as sunrise approached.

“The rain should be generally light,” he said, “but after the main front moves through, about noon, there could be some scattered sunshine, and some scattered thunderstorms.

“There’s an upper-level disturbance, with a lot of cold air, right behind that front,” he said. “By the afternoon, you could have locally heavy rain, some hail and a bolt of lightning here and there. The ground’s still pretty well saturated from the earlier storms, so there’s a possibility of some more mudslides.”

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Sherwin said that as the cold air moves inland this afternoon, snow levels in the mountains should drop from 8,000 feet to about 5,000 feet, with 3 to 6 inches of new snow expected at resort levels.

There was a second, much larger storm churning up the Pacific between Hawaii and the Aleutian Islands on Thursday afternoon. But Sherwin said that one is expected to stay more or less in place, spinning slowly into extinction while reinforcing a massive ridge of high pressure that will settle in along the West Coast by late in the weekend.

He said clockwise circulation around the ridge will generate moderate offshore winds by Sunday that will sweep skies clean and usher in more warm, dry weather similar to--but not quite as hot as--the days Southern Californians enjoyed earlier this week.