After hesitating, storm finally reaches Southland

After hesitating for a couple of days off the coast, the out-of-season winter storm that Southland residents have been patiently awaiting finally moved over land Friday evening, joining commuters for the end of the rush hour in some areas.

The storm, a product of a so-called cutoff or “orphan” low-pressure system, had teased coastal areas including Malibu, Long Beach and western Ventura County with light rainfall for much of the day.

By 8 p.m., radar showed rainfall of various degrees of intensity -- most of it light -- in a ragged, slender pattern from Orange County to Santa Barbara County. It began falling lightly in downtown Los Angeles shortly after 8 p.m.

Bill Hoffer, a spokesman for the National Weather Service in Oxnard, said a flash-flood watch for burned areas would remain in effect “just in case” until this morning, although the storm increasingly appeared to be less intense than expected.

“It looked like it could be a real barn-burner,” he said. “But this thing should spin itself out [by] late Saturday afternoon, when it will become partly cloudy.”

Thunderstorms remain a possibility, although a slight one, throughout the daylight hours today, he said.

Temperatures were expected to be somewhat cooler than normal today and Sunday, with lows in the mid- to upper 50s, and highs in the mid-60s to mid-70s.

The outlook for next week was for normal high temperatures from the lower 70s to lower 80s, Hoffer said.

The low-pressure system formed in the Aleutian Islands and was driven to the L.A. region by an uncharacteristically southern-tending jet stream, said Bill Patzert, lead meteorologist at the Jet Propulsion Laboratory in La Cañada Flintridge.

The jet stream then moved northward again, essentially orphaning the low-pressure system just off Southern California’s coast, where it remained, rotating clockwise and then counterclockwise, as though trying to decide what to do next.

“That’s why the cutoff low is the meteorologist’s woe,” Patzert said. “It was designed by the weather gods to humiliate the TV weathermen, who’ve been telling us for two days its arrival was imminent.”

Patzert predicted that after the storm has run its course, some areas of the region might have recorded an inch of rainfall “and others nary a drop.”

The storm was to bring the Southland its first measurable rain since April 22, when 0.04 of an inch fell.

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james.ricci@latimes.com