Persistent Northwest US Storms to Unleash Feet of Rain, Snow Into Next Week

By Alex Sosnowski, AccuWeather.com Senior Meteorologist

December 5,2015; 9:04PM,EST

 

 

 

As the train of storms associated with El Niño continues to track into the Northwest, colder air will again press across the interior West with more opportunities for snow later next week.
There is no end in sight to the freight train of storms on track for the northwestern United States and southwestern Canada.

Series of Storms Across the Northwest

Storms are lined up for thousands of miles over the northern Pacific.
According to AccuWeather Senior Meteorologist Brett Anderson, "The pattern over the Pacific Ocean is beginning to take on the look of El Niño."

El Niño occurs when tropical Pacific waters are warmer than normal, and the pattern can last several months to a couple of years. During the winter, a strong El Niño can produce frequent storms along part or much of the west coast of the United States.
The El Niño storm train will deliver a heavy cargo of rain, high country snow and gusty winds to coastal areas from northern California to British Columbia.
Through the middle of the month, a few yards (meters) of snow will fall on the higher western slopes Cascades with 1-2 feet (300-600 mm) of rain in coastal areas.

The same pattern will deliver significant moisture to areas east of the Cascades in Washington and Oregon.
The storms will vary in strength and exact path and will generally arrive on the coast every one to three days.
Nearly every storm through next week will bring the risk of flash and urban flooding, coastal flooding, mudslides and sporadic power outages.
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Through early next week, snow levels will be high enough that most storms will bring only rain to low-lying coastal areas and across central and eastern Washington and Oregon.
However, snow levels will be low enough during all or part of the storms to bring periods of accumulating snow and slippery travel to the passes in the Cascades of Washington into early next week.
During the second half of next week, colder air will begin to press southward and inland over the West as moisture continues to stream in from the Pacific Ocean.

The pattern will allow snow to spread southward over the Sierra Nevada and eastward into the various ranges of the Intermountain West and eventually the Rockies. Some rain showers may reach parts of Southern California with the setup starting later next week.
According to AccuWeather Long Range Meteorologist Ben Noll, "The evolution of the El Niño pattern should direct storms farther south [on the Pacific coast] later in December, but more so during January and February."
How wet the pattern gets in Southern California is still uncertain.
According to AccuWeather Senior Meteorologist Kristina Pydynowski, "While some snow may fall over lower elevations of the Intermountain West, the air will still not be cold enough for snow along the Washington and Oregon coasts later next week."
There is a chance the weather may get cold enough to allow a rain and wet snow mix later next weekend to places like Seattle.
Meanwhile, as colder air again dips into the West, temperatures could spring toward record high levels in the Eastern states later next week and next weekend.