Winter Storm Cleon Targets Western U.S.

By: By Jon Erdman

Published: December 1,2013

 

 

 

 

 

 

The Weather Channel has named Winter Storm Cleon, the third named winter storm of the 2013-14 season. Cleon will usher in a period of very cold weather across much of the western and northern U.S., along with zones of significant snowfall.
Let's start with the outlook for snow and ice, beginning in the Northwest.

Snow Forecast: Skier's Delight

Model forecast animation of the upper-level trough, or dip in the jet stream, responsible for the development of Winter Storm Cleon.

• ENLARGE MAP

Monday Forecast

Potential Snowfall Totals

Snow levels will drop Sunday night as a Pacific cold front slides into the Pacific Northwest, bringing snow to lower and lower elevations within the Cascades, Bitterroots, and Tetons through Monday.
Given the trajectory of the attendant upper-level trough diving more toward the south and southeast into the West, cold Arctic air will be pulled not only down the Front Range of the Rockies, but also into the Great Basin and even into the I-5 corridor of western Washington and western Oregon. Thus, a few snow showers are possible even in these low elevations starting Monday.
Before the cold air arrives, heavy rainfall could lead to some localized flooding problems, particularly in western Washington where flood watches have been issued.
The snowfall will create significant impacts to travel through the mountain passes including Sherman Pass in northeast Washington and Stevens and Snoqualmie Passes in the Cascades. Several inches of snow will be likely in the passes with well over a foot at higher elevations of the Cascades through Bitterroots through Monday. Seattle and Portland could see some snow mix in with rain as early as Monday, mainly on the higher hills.
(MAP: 48-Hour Snow Forecast)

Tuesday Forecast

Wednesday Forecast

Potential Snowfall Totals

Tuesday into Wednesday, the deep upper-trough and cold front continue plowing south, spreading snow into the Sierra Nevada, Wasatch and Rockies. While this is happening, another broad area of potentially heavy snow and pockets of mixed wintry precipitation may develop behind the Arctic front in the High Plains of Montana and Wyoming, spreading into parts of the Northern Plains and Upper Midwest.
As the upper level low associated with Winter Storm Cleon moves into Canada, late Wednesday, the trailing cold front will continue to drag bitterly cold air southeast. Thursday, that cold air will act as a trigger for wintry weather in parts of Oklahoma, Texas and far eastern New Mexico.  At this point, the models are in agreement that there will be some accumulating winter weather starting early Thursday and continuing through the day.  The type of wintry weather is a bit trickier to discern with complete confidence.  But current thinking — for central Oklahoma — is that a wintry mix will begin the day and precipitation will completely change to snow by day's end. 
Along with the snow and ice, Winter Storm Cleon will bring some brutally cold temperatures.

Tuesday Highs

Wednesday Highs

Thursday Highs

Decembrrrrrr!

Here is the general timing for the Arctic cold front, by region:

• Monday: Northwest, northern Great Basin, Montana
• Tuesday: California, rest of Great Basin, Wyoming
• Wednesday: Desert Southwest, northern and central Plains, Colorado, New Mexico

Keep in mind the coldest air will lag the arrival of the cold front as laid out in the timing above.
Now, let's lay out the magnitude of the cold by region.

• Pacific Northwest: Highs will be stuck in the 30s from Tuesday through much of next week in western Washington and western Oregon. Lows will be in the 20s, with some teens. Some daily record lows may be threatened.
• California: This will easily be the coldest air of the season, with highs barely reaching into the low 50s in the Bay Area and struggling to rise out of the upper 50s in L.A. and San Diego by mid-to-late week. Lows in the 20s are possible in the Central Valley. Some morning lows near or below freezing are also possible in parts of the high deserts of Southern California and interior parts of the Bay Area such as Santa Rosa and Napa by mid-to-late week. Some daily record lows may be threatened in Northern California.
• Great Basin: Highs in the 20s or low 30s will be common by mid-week. Lows in the teens, single digits, or locally subzero will settle in.
• Desert Southwest: Highs may not rise out of the 50s in Phoenix and may struggle to climb out of the 40s in Las Vegas by Thursday. A freeze is possible in the Vegas Valley late in the week.
• Northern/Central Rockies & Plains: Highs in the single digits and teens will spread from Montana Tuesday to the Northern Plains Wednesday and Thursday. A few spots may not rise above zero during the day. Subzero morning lows will spread from the northern Rockies into the Dakotas and northwest Minnesota by Thursday. A few spots, including Yellowstone National Park and Stanley, Idaho, could see temperatures drop into the twenties below zero.

(MORE: Tom Niziol's Expert Analysis | Winter Storm Central | Winter Safety Tips)
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An overhead view of Barrow, Alaska covered in snow. (Flickr/NASA ICE)