First in series of storms forecast for Southland expected to hit Sunday night

Jan. 03--The new year's first serious bout of wet weather driven by El Ni񯠩s forecast to hit the Southland this week, as several winter storms dump up to 6 inches of rain -- double the normal total for the month of January -- in and around Los Angeles.

The storms, which according to the National Weather Service will begin Sunday night and potentially last through Friday, will bring an increased risk of flooding, mudslides and dangerous surf in a region that so far has had an exceptionally dry winter.

The NWS predicts that the first spell of heavy rain will last from Sunday night through Monday morning. A second, more durable storm system should move over Southern California on Monday and Tuesday nights, bringing up to 4 inches of rain in some areas and possibly more than a foot of snow in the mountains. A final storm is expected to bring moderate rain on Thursday and Friday.

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NWS meteorologist John Dumas said that by late in the week waves could reach 20 feet or higher, with coastal areas in danger of flooding. Dumas said the steady rain could also cause debris flows -- avalanches of mud, trees and boulders that have been known to destroy roads and sweep away houses in the foothills around the L.A. Basin, especially in places recently burned by wildfires.

No single storm is anticipated to unleash the sort of intense, short-term precipitation that creates a particularly high risk of mudslides and flash floods.

Nevertheless, after lower-than-average rainfall in November and December, this week's steady torrent should be "a pretty dramatic whiplash," said Bill Patzert, a climatologist with NASA'S Jet Propulsion Laboratory in La Ca񡤡 Flintridge.

Patzert said the wet weather will also be a sobering taste of what is likely in store for the rest of the winter, as abnormal weather patterns generated by the El Ni񯠰henomenon aim a stream of heavy storms directly at Southern California through March. "I think this is the beginning of the beginning," he said.

El Ni񯠯ccurs during periodic warming of the equatorial waters of the Pacific. The change wreaks havoc on normal climatic conditions, weakening South Asia's monsoons and bringing heavy rain to the typically dry coastline of Central and South America. El Ni񯠡lso alters the course of the jet stream, targeting California with the wet weather ordinarily directed at the Pacific Northwest.

El Ni񯠳torms generally peak in California in January, February and March.

Climate scientists are predicting that this year's El Ni񯬠one of the most powerful on record, could create especially severe conditions in the Southland. Many local officials and homeowners have been busy preparing for a wetter-than-average winter, clearing culverts and catchment basins and stocking up on sandbags.

Last month, the Los Angeles City Council allocated $12.4 million for emergency relief to get homeless people off the streets before the the potentially disastrous storms approach. The city has been under fire for delaying action to safeguard the estimated 18,000 people who live on the streets.

Previous El Ni񯠰atterns brought dangerous storms to California in 1983 and 1998. During the latter winter, the state sustained more than half a billion dollars' worth of damage.

peter.jamison@latimes.com