Rounds of Snow Will Continue in the West, Spreading into the Northern Plains and Upper Midwest This Weekend Into Early Next Week
Published: February 15, 2018
More heavy snow will continue to make skiers happy in parts of the mountain West, and some of that heavier snow will spread into parts of the Plains and Upper Midwest this weekend into early next week.
(MORE: Winter Storm Central)
This is largely due to a fundamental shift in the jet stream pattern that is a classic look of February in a La Niña winter, featuring a sharp southward plunge into the West and a northward migration over the East.
The forecast jet stream pattern in place Monday, Feb. 19, featuring the sharp southward plunge in the West, which will help generate mountain snow.
There will be two main rounds of snow through early next week. Let's break down each round and lay out not only the West snowfall you can expect, but how much will spread into the Plains and Upper Midwest.
Round 1: Through Friday
A jet-stream disturbance and associated Arctic cold front are currently moving through the Rockies, spreading snow across the northern Rockies. Another disturbance immediately behind it will sweep quickly through the Northwest and northern Rockies tonight into Friday.
Current Radar and Conditions
The National Weather Service office in Spokane, Washington, measured 8.7 inches of snow Tuesday night into Wednesday while 7.3 inches was reported by a weather observer at Spokane International Airport.
Interstate 15 in Montana was closed early Wednesday evening from Shelby to the Canadian border due to severe driving conditions from a combination of falling and blowing snow. Multiple slide-offs were also reported along Highway 93 in the area of Somers, Montana.
Overnight Wednesday night, sheriff's offices in 14 Montana counties urged travel for emergencies only due to blowing and drifting snow.
Winter storm warnings and winter weather advisories continue in effect in Montana, Wyoming, Colorado, far southeast Utah and the high country of northern New Mexico.
At least 6 inches of additional snow is likely in the northern Rockies and high country of Colorado through Thursday. Unfortunately, no additional snow will fall in the Sierra from this round.
Most low-elevation cities such as Salt Lake City won't see snow from this round. However, some modest accumulations are expected in Flagstaff, Arizona, and Billings, Montana.
Some snow will spread out into the northern Plains and northern Great Lakes Thursday.
(MAP: 48-hour Snowfall Forecast)
Round 2: Weekend/Early Next Week
Another vigorous jet stream disturbance will plunge into the Pacific Northwest Saturday, then carve out a sharp jet-stream plunge through much of the West this weekend, sending waves of disturbances into the Northern Plains and Upper Midwest into early next week.
This will manufacture yet more snow for the Cascades and Rockies.
This snow is also desperately needed for water supply concerns, replenishing what has been a paltry snowpack in parts of the southern Rockies, Wasatch and Oregon Cascades.
Unfortunately, snowfall amounts in the snow-starved Sierra will once again be rather unspectacular, by mid-February standards.
(MORE: Snow Ratios: An Important Role in Snowfall Forecasting)
As colder air spills into the Northwest, snow levels will drop by Sunday, possibly allowing snow to fall as low as the lowlands near Puget Sound in the Seattle metro area.
Areas of moderate to locally heavy snow will also spread out into parts of the Northern Plains and Upper Midwest this weekend into early next week.
(MAPS: 7-Day U.S. Forecast Snow/Rain)
The exact placement of the areas of heavier snow in these areas still remains somewhat uncertain, but at least some snow looks possible in both Denver and Minneapolis/St. Paul, from this event.
Check back with us at weather.com for updates in the days ahead.
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