SEATTLE — Northern California and the Pacific Northwest are bracing for a powerful storm that will hit the region with heavy rain and winds, potentially leading to power outages and flash floods.

The Weather Prediction Center reported the strongest risk of extreme precipitation starting on Tuesday and continuing through Friday. atmospheric river Long clouds of moisture extending far beyond the Pacific Ocean have seen California and the Pacific Northwest wreak havoc on the region this season. The storm system intensified so quickly that “ bomb cyclonesaid Richard Bann, a meteorologist with the National Weather Service Weather Prediction Center.

Areas likely to see particularly heavy precipitation will likely extend from south of Portland, Oregon, to north of the San Francisco area as the large moisture cloud heads landward, the official explained.

“Be aware of the risk of flash floods at lower elevations and winter storms at higher elevations. “This will be a very effective event,” he said.

Flood and high wind watches go into effect Tuesday in Northern California, with up to 20 centimeters of rain expected in parts of the San Francisco Bay Area, the North Shore and the Sacramento Valley.

A winter storm watch has been issued for the northern Sierra Nevada above 3,500 feet (1,066 meters), where 15 inches (28 centimeters) of snow is possible for two days. Winds could gust up to 75 miles (120 kilometers) per hour in mountainous areas, forecasters said.

“Expect multiple flash floods, hazardous travel, power outages and tree damage as the storm reaches maximum intensity,” the Weather Prediction Center warned Wednesday.

Meanwhile, Southern California will experience dry conditions this week strong Santa Ana winds This could increase the risk of wildfires in areas where crews are still trying to clear the massive blaze that destroyed 240 structures. Mountain FeverThe storm, which broke out in Ventura County northwest of Los Angeles on Nov. 6, was about 98% contained by Monday.

Winds will calm down by the end of the week, when rain is possible in the greater Los Angeles area.

In southwestern Oregon near the coast, 4 to 7 inches (10 to 18 centimeters) of rain (as much as 10 inches (25 centimeters) possible in some areas) was forecast from late Thursday night through early Friday morning, Bann said.

A high wind warning has been issued for the northern and central Oregon coast effective Tuesday at 4 p.m.; South winds are expected to range from 25 mph (40 km/h) to 40 mph (64 km/h), with gusts up to 60 mph (97 km/h). Weather service in Portland. Winds up to 70 mph (113 km/h) are possible along the beaches and headlands. Widespread power outages are expected, with winds that could knock down trees and power lines, the weather service said. Travel is also expected to be difficult.

Washington may also experience heavy rainfall, but probably not as bad as Oregon and California. From Monday evening through Tuesday, some coastal areas could receive as much as 1.5 inches (3.8 centimeters) of rain, Bann said.

The weather service warned of high winds Tuesday afternoon into early Wednesday for coastal parts of southwestern Washington’s Pacific County. The Pacific County Emergency Management Agency warned that trees and power lines were at risk of downed trees and power lines, with winds exceeding 30 mph, potentially faster near beaches and headlands.

Washington State Patrol Officer John Dattilo, a Tacoma-based patrol spokesman, posted on social media Monday afternoon that people should be prepared for “some bad weather” Tuesday night. “Stay off the roads if possible!”

A blizzard warning was issued Tuesday afternoon for much of Washington’s Cascades, including Mount Rainier National Park, with up to 1 foot of snow and winds up to 60 mph, according to the weather service in Seattle. . Traveling between passes can be difficult, if not impossible.

Outside of that area, the central and eastern Gulf Coast, including the Florida Panhandle, are at risk of flooding Tuesday, with 2 to 3 inches (5 to 7.6 centimeters) of precipitation in the forecast, according to the weather service. Flash floods may occur in low-lying and urban areas.

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Associated Press reporter Lisa Baumann contributed to this report.