Heavy Rain Expected in Southland

An arctic storm system intensified unexpectedly off the coast of Southern California on Friday night, bringing the promise of heavy rain today in Southern California and substantial snow in the surrounding mountains.

“It’s something to be reckoned with,” meteorologist John Sherwin said Friday night. “It’s a pretty powerful storm by now.”

The rain should start falling shortly after dawn and continue, off and on, into tonight, he said. A few lingering showers may dampen some Easter egg hunts Sunday morning.

The snow level will start at about 7,000 feet this morning, dropping to about 4,500 by sunset, Sherwin said. He said as much as 10 inches of snow could fall at mountain resorts, where ski conditions continue to be unusually good for this time of year.

The intensification of the storm caught forecasters by surprise.

On Friday afternoon, faced with computers that couldn’t agree, the forecasters had been having trouble deciding whether any rain would fall from what then seemed to be a relatively benign weather system that was hovering a few hundred miles west of Point Conception.

The same thing had happened last weekend with another storm that was pretty much in the same place.

That time, most of the forecasters crawled out on a limb, saying that the storm probably would move inland over Orange and Los Angeles counties on Sunday and drop some steady rain, possibly messing up the Long Beach Grand Prix. Instead, the storm came onshore well to the south--in Baja California--the basin got a lot less rain than expected and the Grand Prix went off without a hitch.

Because of that, the forecasters started out on the cautious side this time.

“I think there will be some showers lasting 15 minutes or so, but I don’t see any steady rain,” Sherwin ventured Friday afternoon.

National Weather Service meteorologists in Oxnard put out a forecast on the news wires Friday afternoon that it probably would rain in Orange County today.

More privately, however, they conceded in their interoffice discussions--which can be unearthed on the Internet--that the two computer models on which their forecasts are largely based were in sharp disagreement.

The discussions revealed that one model wanted to “toss a meteorological spitball” at Southern California, complete with heavy rain and “screaming” winds, while the other would “leave us much drier” and perhaps “leave us alone entirely.”

Concluding that “it is likely that both models will be off the mark,” the agency at about 6 p.m. Friday chose the compromise of rain “likely” today.

They probably should have gone with the spitball.

Sherwin, who stayed at his post a little longer, said he noticed in satellite pictures taken an hour later that high altitude jet-stream winds swirling around the storm were “energizing” the system.

Although the storm system should move out pretty rapidly Sunday afternoon, forecasters say there will be increasing cloudiness and a chance of sprinkles Monday.