Bomb cyclone to drop inches of rain, snow on the Pacific Northwest

PORTLAND, Ore. (KOIN) — A bomb cyclone fueled by an atmospheric river will swing by the Pacific Northwest this week, bringing heavy rain and snow to the region between Tuesday night and Friday morning.

The coast will see the strongest impacts, with 3.5 to 6 inches of rain expected between Tuesday and Friday night. The inland valleys, including Portland, Salem and Eugene, will likely receive 1.5 to 3 inches of rain. The heavy rain could potentially cause flooding in city streets.

KOIN 6 Meteorologist Kelley Bayern forecasts that the bomb cyclone will remain offshore, protecting the Portland area from more serious storm damage.

“Models are classifying it as a ‘bomb cyclone’ due to its rapid intensification,” Bayern said. “Thankfully, this storm is modeled to stay well offshore, otherwise, we would be talking about a potential strong windstorm in the valley. It will still bring in heavy rainfall along the West Coast as it veers by.”

The storm will also bring periods of moderate to heavy mountain snow. Causing potentially hazardous driving conditions through mountain passes. The National Weather Service has issued a winter weather advisory for the Coast Range and a winter storm warning for the Cascades Monday as heavy snow is already falling in the mountains. More weather advisories are anticipated for the rest of the week.

On Monday, 2 to 5 inches of snow is possible along the Coast Range in areas above 2,000 feet of elevation, Up to 9 inches of snow is possible in areas above 2,500 feet. The Cascades are forecast to receive 6 to 10 inches of snow by 10 p.m. Monday. Snow levels are expected to hover between 5,000 and 6,000 feet for the rest of the week.

“Travel impacts over the Cascades passes are expected,” the NWS warns. “Anyone planning to travel over the passes today should be prepared for winter driving conditions.”