Next Winter Storm Blasts First Arctic Air of the Season Into West, Plains This Week

Linda Lam
Published: November 22,2015

An impressive arctic blast will engulf the West and Plains this week, setting the stage for a significant winter storm.
A cold front will move into the Pacific Northwest Monday and Tuesday bringing rain and mountain snow to the region. This low-pressure system will then spread snow across the northern and central Rockies midweek. Snow may even accumulate in the valley floors.

Western Storm Setup

This system will then move through the Rockies and into the Plains mid-to-late week potentially bringing moderate to heavy snowfall along with ice.
(MORE: Thanksgiving Travel Forecast)
A strong arctic high-pressure system will then move in behind this system allowing the first real blast of arctic air to surge into the U.S. The coldest air mass of the season to date is expected for the West and the Plains beginning Wednesday and lasting into the start of the weekend.

Another Winter Storm

Rain and mountain snow will first develop in the Pacific Northwest on Monday as this approaching low-pressure system pushes into the region. This area of low pressure will continue sliding south and east through much of the West early-to-midweek.
Seattle and Portland will see rain Monday and into Tuesday while accumulating snow will fall in the Cascades with snow levels dropping to around 1,000 feet.
(FORECAST: Seattle | Portland)
Showers are then expected to expand along the West coast, including much of central and southern California Tuesday and possibly lingering into Wednesday. Snow will fall through the Sierra Nevada as well as the Inter-Mountain West. Snow levels in the Sierra are expected to drop to 2,000 feet, with up to a foot of snow possible in the higher elevations.
Snow levels will remain low through the West, with accumulating snow expected in more populated areas than compared to the last few winter storms.

Snowfall Forecast

A winter storm watch has been issued for western Montana, northern Idaho, and northeastern Washington. Winds will be gusty at times, which could create near-blizzard conditions on Tuesday.
If you are traveling midweek for Thanksgiving, delays are anticipated across much of the West, including Interstates 15 and 80 in Utah and Wyoming, as well as Interstate 90 in Montana and possibly sections of Interstate 70 in Colorado.
(FORECAST: Boise | Missoula | Salt Lake City)
Upslope flow may also develop on the eastern side of the northern and central Rockies which would enhance the snowfall along the Front Range.

Arctic Blast

The upper-level trough, or southward dip in the jet stream, will dive across the West midweek and combined with a strong area of high pressure from Canada, the result will be the first blast of arctic air arriving in the West and Plains.
Low temperatures will be up to 25 degrees below average in portions of the Pacific Northwest and Rockies Thursday and Friday mornings.

Morning Forecast Lows

Overnight lows will range from single digits to well below zero in the northern and central Rockies beginning Thursday morning and lasting until Saturday morning.
This will lead to the coldest temperatures so far this season. A couple of examples include Helena, Montana where the lowest temperature recorded so far this season is 14 degrees and lows are expected to drop to around zero this week. Reno, Nevada has seen the mercury drop to 21 degrees and lows in the teens are in the forecast this week.
Temperatures will likely drop into the upper 30s at the San Francisco International Airport late this week and a new daily record low may be set on Friday morning (current record is 37 degrees).
(FORECAST: Great Falls, Montana | Casper, Wyoming | Denver)
Wind chills may plummet between 20 to 25 degrees below zero in these areas Wednesday night and again Thursday night.

Forecast Highs

High temperatures will remain very cold as well. Highs will be 10 to 30 degrees colder than what is normally expected for the end of November through the West Wednesday through Friday. Highs will only reach the 10s and 20s in the Rockies with 30s and 40s for the Pacific Northwest and Great Basin.

Snow and Chilly Conditions Move Into the Plains

Late Week Setup in the Plains

The arctic chill will push south and east late this week and into the weekend. High temperatures in the Plains will be up to 25 degrees colder than average beginning Thanksgiving and persisting into the holiday weekend.
(FORECAST: Rapid City, South Dakota | Oklahoma City)
High temperatures in the central and southern Plains will only climb into the 20s and 30s, with 40s for highs as far south as Dallas.
These cold temperatures will allow snow and/or ice to fall in parts of the Plains late this week. Ahead of the cold front, rain and thunderstorms are expected and a few severe thunderstorms are possible from southern Kansas into Texas Thursday into Friday.
(FORECAST: Amarillo, Texas | Dallas)
Behind the cold front, snow will begin to develop in South Dakota and Nebraska Wednesday night and into Thursday. By Thursday night, snow and ice may be concerns in portions of the southern Plains including western Kansas, western Oklahoma, and the Texas Panhandle.
(MAPS: Weekly Planner)
Upper-level disturbances may continue to move through the southern Plains into the weekend. This setup would allow freezing rain and snow to continue at times, especially in western Texas Friday and Saturday. These conditions may create slick and dangerous travel conditions.
MORE: Winter Storm Bella (PHOTOS)