Clearing Due but a New Storm Is Hovering

Bands of showers moved through Southern California over the weekend and were expected to drop about an inch of rain in the Los Angeles Basin by the time skies clear later today.

The quirky storm surprised forecasters, who had predicted only a slight chance of light rain.

Instead of moving through Southern California, a low-pressure system simply sat about 500 or 600 miles off the coast, generating more rain than had been forecast.

“Our computer models just do not do a good job on these kinds of storms,” National Weather Service meteorologist George McKillop said. “A typical storm moves on, giving us rain one day in California and snow in the Rockies the next. It’s like if you toss a Frisbee into a creek, it flows downstream. That’s predictable. It’s called a ‘trough.’

“But this turned into what we call a ‘cutoff flow.’ It’s like the Frisbee got caught in an eddy and didn’t move. . . . You can’t always predict when that will happen.”

The rain gauge in downtown Los Angeles measured .38 of an inch by 4 p.m., bringing the season total to 8.18, compared to the 11.07 that would be normal for the date.

Other rainfall amounts included 2.60 atop Mt. Wilson, 1.40 in Northridge, .87 in Woodland Hills, .79 in Culver City, .58 in Monrovia, and .37 in Santa Barbara.

No serious power outages or traffic accidents were attributed to the storm.

The roots of a 100-foot tall oak tree perched on a hillside above Laurel Canyon Boulevard were apparently loosened by the rain and the huge tree toppled across the street near Lookout Mountain Avenue, tying up motorists for three miles in both directions until police redirected traffic.

A resulting power failure cut off service for about two hours to 1,600 homes in the surrounding area. Also affected was nearby Los Angeles City Fire Station 97, where one harried firefighter said, “We’re working in the dark up here, we’re getting all of our calls on the radio.”

McKillop said another half an inch was expected to fall in some areas of the Los Angeles Basin on Sunday night.

Dry and mild temperatures are expected for Tuesday and Wednesday. But a new storm building off the coast of Alaska is expected to bring more wet weather by Thursday or Friday, forecasters said.

“It’s a strong storm and the Southland will get a piece of it,” said Dan Bowman of WeatherData Inc., which provides forecasts for The Times. “The system doesn’t have a heck of a lot of cold air, so temperatures should stay in the mid-60s to 70.”

Sunday’s high reached 67 at the Los Angeles Civic Center after an overnight low of 59. Relative humidity ranged from 65% to 100%. A similar reading is expected today.