An area of low pressure will approach the California coast on Sunday and will bring with it a slug of moisture straight from the tropics.

LOS ANGELES – A rare extreme flash flood risk has been issued in due to the imminent arrival of a potent atmospheric river this weekend that promises to dump several inches of rain across the region.

The is the highest rung on NOAA’s flash flood threat scale, and is only issued under the most dire of flooding forecasts.

“The probabilities of 8-plus inches of rain in 24 hours are high enough to introduce a High Risk for portions of the Southern California Transverse ranges,” NOAA’s Weather Prediction Center (WPC) said. 

Some areas in the mountains could see more than 10 inches of rain throughout the event.

Flash flood threat
(FOX Weather)


But the flooding risk isn’t confined to the mountains. Even the urban areas of the Los Angeles metro area face an onslaught of multiple inches of rain and a significant flooding risk. 

The NWS in is using strong language in its forecasts, indicating a significant threat for widespread and dangerous flash Sunday into Monday.

The National Weather Service office in Los Angeles warned that issues will not be confined to the usually-prone areas in the foothills, mountains and burn areas.

“ALL AREAS, INCLUDING HIGHLY POPULATED URBAN AREAS, WILL BE AT RISK FOR LIFE-THREATENING FLOODING,” NWS Los Angeles forecasters wrote in all caps for emphasis during their weather discussion Friday night. “Streams and small rivers, as well as the Los Angeles River through the San Fernando Valley and metro LA will rise quickly and turn into very dangerous raging rivers. Many roads will be impassable due to flooding.”

The NWS also warned numerous mud and rock slides are expected in the foothills and mountains.

Moist, unstable air will likely trigger scattered strong to even a few severe along and just off the coast. Some storms could spawn waterspouts Sunday afternoon across the central and southern coastal waters from the Santa Barbara channel north past Monterey. A brief tornado or two is also possible where any waterspouts blow ashore, the NWS said.

Sunday severe weather threat
(FOX Weather)


NOAA’s Storm Prediction Center has issued a Level 1 out of 5 risk for possible severe thunderstorms along the coast, stretching just inland to cover cities like San Jose and Salinas.

‘Extreme’ rainfall totals possible across Southern California

An area of low pressure will aim another atmospheric river toward the California coast late Saturday into Sunday and bring a slug of moisture straight from the tropics, according to the FOX Forecast Center. 

Unlike the last system, this storm won’t be in a hurry to leave. That will keep the atmospheric river of moisture pointed at California for two to three days. 

Expected rainfall amounts
(FOX Weather)


“The last atmospheric river event that we went through, there was movement,” FOX Weather Meteorologist said. “This time, there’s going to be less movement, which means extreme rain totals.”

While all of California will get in on the rain, it is becoming clear that areas of most concern will be along the southern coastal ranges down through the Los Angeles Basin. The heaviest rain arrives Sunday through Monday, with peak rain Sunday night.

The Los Angeles metro may see 5 inches of rainfall or more Sunday into the middle of the week. Los Angeles only averages just over 14 inches of rain per year. As mentioned earlier, the surrounding mountains and their foothills could see 10-12 inches of rain.

Rain forecasts for Los Angeles area through Wednesday, Feb. 7.

(FOX Weather)

“This is the type of rain that they cannot handle,” Merwin said. “This is a guaranteed flood setup. There’s no way around it. We know it’s going to be bad, and there’s going to be huge impacts.”

Evacuation orders issued for some Southern California neighborhoods

This storm , and the soil in Southern California is already super-saturated. Thursday’s record rainfall of 2.45 inches in Long Beach flooded highways, including the busy Interstate 710. Los Angeles also set a daily record with 2.49 inches of rain.

“Everyone, especially those near or in south-facing mountains, needs to start preparing now for possible evacuations during or even before the storm hits,” NWS Los Angeles forecasters said.

Rain forecasts for San Diego area through Wednesday, Feb. 7.

(FOX Weather)

Evacuation warnings were issued for parts of low-lying Santa Barbara County on Friday, and heightened evacuation orders were issued for some campgrounds and coastal communities on Saturday.

Aside from the High-Risk area in the mountains north of Los Angeles, a Level 3 out of 4 risk for flash flooding covers urban areas just north of Los Angeles all the way up the coast toward the Bay Area. The Level 3 risk shifts a bit south to the Los Angeles-to-San Diego corridor on Monday.

Here’s a look at the flash flood threat in California through Tuesday.

(FOX Weather)

“It shows you the confidence that we know this is going to be a bigger storm,” Merwin said. “It has a lot more moisture to it. There’s a much larger flood threat for Southern California.”

Due to the threat, the NASCAR Cup Series and NASCAR Mexico Series race events that were scheduled for Sunday were moved up a day to Saturday, in order to take advantage of the drier weather.

Why high-risk days are so serious

High Risk forecasts are only issued on about 4% of days (including tropical and non-tropical events), but this risk category accounts for 39% of flood-related fatalities and 83% of flood-related damages in the continental , according to .

What’s more, 46% of high-risk flood days have at least one fatality or injury, and 62% of such days have at least $1 million in damages, , forecast operations branch chief at the WPC, noted .

The last High-Risk flash flood threat day in the U.S. was Aug. 20, 2023, and corresponded with moving inland across Southern California.

Several feet of snow likely in Sierra Nevada

The plume of moisture will generate a significant storm for the Sierra Nevada, with 4-6 feet of snow likely above 5,000-6,000 feet, the FOX Forecast Center said. Disruptions to daily life, including difficult to impossible conditions, are expected. 

In the mountains of Southern California, snow levels are expected to be around 7,000 feet, but above that level, 2-4 feet of snow is possible.

A significant winter storm is anticipated for the Sierra Nevada, with several feet of snow likely above of 5,000-6,000 feet.

(FOX Weather)

Damaging winds possible around San Francisco, central Coast

In addition to the heavy rain threat, damaging winds are in the forecast for the central California and southern California coasts toward , and even into parts of the Bay Area. 

High Wind Warnings are already posted for gusts along the coast and coastal mountains reaching 50-60 mph. Wind Advisories warn of possible gusts to 50 mph in the San Francisco Bay Area.

Wind gust forecat
(FOX Weather)


Even stronger winds are likely in the mountains around Southern California, with gusts reaching as high as 70-80 mph. 

Gusts topping 40-plus mph will likely extend well inland into the Central Valley. These winds will have the potential to bring down many trees and cause numerous power outages. 

At the coast, these winds will also whip up the Pacific into a frenzy with 10-20 foot waves likely to slam into beaches up and down the state.

Moisture streaming in behind the storm will keep periods of rain in the forecast through much of next week, though there will be longer dry periods between the showers to wring out.