The worst of the SoCal Rainstorm that was supposed to hit Sunday and Monday

The worst of the first significant rain storm of the season for Southern California is expected to hit Sunday and Monday. Here’s what you need to know:

Timing

Forecasters with the weather service issued a flash flood watch for the burned areas of the recent La County fires for the time period of highest risk – from 10 Sunday to 16 Monday.

At As of 3 p.m. Sunday, a handful of locations in western Los Angeles County had received a half-inch of rain, according to the Weather Service. Downtown Los Angeles received 0.32 inches of rain. There were also reports of streets flooding in the LA area due to blocked drains.

“We still have some showers coming up from the south,” said Carol Smith, a meteorologist with the National Weather Service. “More is coming.”

Sunday night will be the period of particular concern, officials said.

This is “a slow moving storm so it will be stubborn. It will hang around,” said Alex Tardy, a meteorologist with the National Weather Service Office in San Diego. “It will send waves of moisture through Monday. So I think it will really add significant rain and snow. “

Forecast

Mountains in Los Angeles and Ventura counties could get 2 to 3 inches of rain, while a half inch to 1 inch is possible elsewhere.

Through Monday, Covina could receive 1.32 inches of rain; Downtown LA, 1.14 inches; Long Beach, 1.12 inches; Canoga Park, 1.05 inches; Santa Clarita, 1.04 inches; Fillmore, 1.02 inches; Redondo Beach, 0.95 inches; and a thousand oaks, 0.87 inches.

If the storm produces rain on the higher end of the estimates, from 1 to 1.5 inches of rain could fall in Orange County, Ontario, Riverside, Lake Elsinore, Temecula and coastal northern San Diego County. From 0.7 to 1 inch of rain could fall in San Diego and from 1.5 to 2 inches in San Bernardino.

Flooding problems in the combustion area

A flood watch is issued when weather conditions are favorable for flooding. “This does not mean that floods will occur, but they are possible“Says weather service.

A portion of the Pacific Coast Highway was closed Sunday afternoon due to flooding in Topanga Canyon, according to meteorologist Joe Sirard of the National Weather Service’s Office in Oxnard. A rain gauge picked up 0.74 inches on Topanga Canyon Boulevard at the edge of the fire line, he said.

Forecasters have increased their projections of how much rain could fall. The adjusted forecast is a result of the low pressure system moving in from Canada, which appears to weigh a little more to the west — a little more off the coast of Southern California — than originally expected, which would make this storm wetter .

That results in the “increased concerns about debris flows over some of the burn scars,” Kittell said.

Still, significant uncertainty remained Saturday afternoon, with results dependent on the storm’s exact path and speed, said Kristan Lund, a meteorologist with the National Weather Service in Oxnard.

If the low pressure system swings a little west toward the water, it will pick up more moisture and result in higher precipitation totals, while a more inland route to the east will mean less rain, she said. And if the storm ends up being a little slower than expected, it could sit over an area and prolong rainfall there or result in heavier rainfall everywhere, she said.

“These patterns tend to be a little more unpredictable with regard to you, you really don’t know until it arrives what it’s going to end up doing,” she said.

Forecasters said there is now a 10% to 20% chance of significant flash flooding and debris flows capable of damaging roads and homes in the most vulnerable recently burned areas, the Palisades and Franklin areas around the Pacific Palisades and Malibu, the Eaton fire around Altadena and Pasadena, the Hughes fire around Lake Castaic and the bridge fire in the Angeles National Forest north of Glendora.

Preparation

Among the Weather Service’s recommendations: Avoid recently burned areas during this period. Use sandbags to protect property. And residents who decide to stay can “stock up on supplies in case access to the road is blocked.”

Context

The rain is expected to snap a record or near record, streak of dry weather for Southern California. Most areas in the region have received less than 5% of the average accumulated rainfall for this point in the water year that began October 1.

As of late Saturday, downtown Los Angeles had received just 0.16 of an inch of rain since Oct. 1, which is just 2% of the average for this time of the water year — 6.48 inches. Downtown LA’s annual average rainfall is 14.25 inches.

On Saturday night, 0.11 of an inch of rain fell on downtown LA

Southern California is now either in “extreme drought” or “severe drought” according to US Drought Monitor.