Heavy rainfall hits L.A. County, before moving to Orange County and Inland Empire

The first of a series of heavy storm systems began dropping rain on Los Angeles County early Thursday morning, Feb. 1, leading to some roads flooding, and widespread rain was expected to continue into the late-morning hours before easing up to scattered showers later in the day, authorities said.

Already, western portions of Los Angeles County, including Manhattan Beach and Hermosa Beach, had seen more than an inch of rainfall as of 7:30 a.m., said Rose Schoenfeld, a National Weather Service meteorologist. Other areas in the county had seen between a half-inch and three-quarters of an inch.

Areas in Orange County and the Inland Empire had mostly seen a half-inch or less, but heavier rain was anticipated as the widespread portion of the storm shifts from Los Angeles County down toward those areas, said another Weather Service meteorologist,  Philip Gonsalves.

Fullerton had the highest amount in Orange County as of 7:30 a.m. at about a half inch. The Pomona gap, which splits the Santa Ana and San Gabriel mountains, had seen just under half an inch, Gonsalves said.

Areas in the Inland Empire had seen less than one-tenth of an inch so far.

“We fully expect to see that sort of intensity of rainfall slowly migrate into Orange County,” Gonsalves said. “It’s a gradual process.”

With that, Gonsalves said the office was expecting the rainfall to lead to road flooding in parts of Orange County. As of 7:30 a.m., Schoenfeld said her office was seeing some reports of road flooding in L.A. County.

Weather experts expected the heaviest rainfall to move on from Orange County and the Inland Empire sometime around 2 p.m., but chances for showers would remain across the region into Friday morning. In all, the first wave of storms was anticipated to bring between an inch and a half to two inches of rain in most common areas, with upwards of three inches anticipated on southern facing slopes.

“The two things about this are the rainfall amounts and the threats for flooding and the winds,” Gonsalves said, adding that areas in Orange County were seeing gusts up to 30 miles per hour.

Snow accumulations could come down to about 5,500 feet later in the day, Gonsalves said. Weather experts said the chance of snowfall affecting the Grapevine was unlikely overnight, but Schoenfeld didn’t rule it out depending on when showers hit.

A second storm system was expected to start dumping rain on Los Angeles County Saturday night into Sunday morning, Schoenfeld said. That storm would bring more widespread and continuous rain, possibly for up to between 24 and 36 hours.

“The storm total is looking to be pretty impressive,” she said. “We’re going to see some pretty heavy rainfall and that’s going to lead to the possibility of rock and mud slides in vulnerable areas as well as roadway and urban flooding.”

That storm, anticipated to last into Tuesday, could bring as much as four inches to some areas of Southern California and could double for southern facing slopes, with peaks of one-inch per hour, Schoenfeld said.

“Avoid driving if you can and drive cautiously if you are,” she said. “Take a lot of caution with that.”

Source: Orange County Register