Bomb cyclone, Here it Comes!

What is a bomb cyclone?

Bomb cyclones are low pressure systems that undergo what meteorologists call "bombogenesis." Bombogenesis occurs when a midlatitude cyclone ("midlatitude" meaning the area between the tropics and the polar regions) rapidly intensifies over a 24-hour period.  

The Forecast

A major component of the storm will be a long plume of moisture directed at portions of the Pacific coast, That plume, known as an atmospheric river, will act like a massive firehose of rain at low elevations and a giant snow gun over the high country.

Snow levels will vary during the storm--starting off at pass levels then rising above and falling back to pass levels in the Cascades, Siskyous and northern Sierra Nevada. Several inches to a foot of snow can fall over the passes in the Cascades on the front and backside of the storm. Where all snow falls over the high ground, a few feet can pile up. During much of the time when snow falls, strong wind gusts and snow can create blizzard conditions over the passes and high country.

From Tuesday night to Wednesday, the atmospheric river will be mainly directed at the Oregon and Northern California coasts. In this area, from 8-12 inches of rain will fall from Tuesday to Friday with an AccuWeather Local StormMax™ rainfall of 20 inches.