ATMOSPHERIC RIVER IS AIMED AT THE PACIFIC NORTHWEST AND SIERRA WITH LEFTOVERS HITTING THE ROCKIES
Update. 1/16/2018 PM Report
Many areas of the west are in the line up for several periods of snowfall with a cooling trend and a moderate Atmospheric River. The Seattle coast is expecting 20-30 foot waves on Thursday! The week ahead looks deeper and colder finally with low elevation snow. Its not an arctic blast, but certainly more in line with normal temps for January, if not still slightly higher. The East gets teased with a southern storm where I would chase to the Berkshires, southern Vermont, or areas of southern New Hampshire (Gunstock might work). Chase now as most snow is happening Wednesday (Crowd free sneak up powder day). The Berkshires could nab 5-10 inches by last chair Wednesday. The snow totals in the east have crushed many areas of the west this season!
In the west an atmospheric river is developing in the Pacific Northwest that is going to push ample moisture from the WA and Oregon Cascades into the Sierra. Very warm temps Wednesday (7,000 foot snow levels in the southern Cascades) will give way to mixed rain and snow changing to all snow by Thursday morning (Midnight to 3AM cooling to the bases). Significant snow will be falling early Thursday for your 1st chairs. Significant blowing and drifting of snow is likely Wednesday night with 70 MPH gusts before diminishing Thursday morning (Conditions are either going to be all time buff smooth with powder or mixed cream, blower, drift, oh SHXX bumps). Its a gamble worth chasing for. Mount Baker should nab 2 feet or more with the SW wind direction pumping moisture north. All other areas should see 12-18 inches by Late Thursday (Higher amounts near Baker). The entire Cascade range from Oregon through Washington is going to reap deep rewards through Thursday. Light to moderate snow showers continue at all elevations (Snow level drops each day this week) through the weekend with an additional 3-7 inches each day (Timing and specifics to follow on a future post). The Good: Very deep moisture for the next 5 days (Thursday and Sunday peak). The Bad: Strong winds Wednesday night and high snow levels may bring variable conditions to lower elevations. Brief break perhaps Friday or Saturday?
The Sierra gets deep Thursday night into Friday morning with the coldest air of the season. It starts out windy and warm Thursday and finishes cold and deep for 1st tracks Friday. My estimate is 15-20 inches along the Sierra Crest (Northern areas favored), 6-10 inches lower elevations, and perhaps 12-16 inches for southern ski areas including Mammoth. I like the north better than the south on this storm. Chase around the lake on Friday for deep snow at mid mountains and the summits for 1st chairs. The Good: Great snow on top for Friday. The Bad: The lower elevations are in need of much more snow (May happen by Tuesday).
Idaho, Montana, and Wyoming get strong leftovers aimed primarily at central Idaho (Brundage might get lucky but prefer west winds versus SW). SW Montana especially Big Sky should see 3-7 inches by Friday morning. Sun Valley is a wildcard and might not tip the scale past 3-5 inches Thursday afternoon (Just north into Stanley see’s higher amounts). The Tetons get into action late Thursday into Friday. Expect 4-8 inches overnight Thursday and another 3-5 inches possible during Friday. Storm totals may end up at 7-12 inches. The Good: Moderate snow for early Friday. The Bad: Warm temps Thursday night will limit any epic dumps and may bring a fairly dense layer to mid elevations. Rain may be falling at the base of JHMR at times before changing to all snow Friday before daybreak.
The Wasatch gets a good cold front with 3-6 inches in most mountain locations near Park City and north. The Cottonwoods are likely to have 4-9 inches by late Friday (Models are flip flopping somewhat but my confidence is decent). Long term looks much deeper later in the weekend. If NW flow kicks in Saturday amounts may be deeper.
Colorado grabs an interesting mix of wind shifts greatly impacting where it will be snowing this week. The latest models show decent SW flow over the 4 corners for Saturday morning. Wolf Creek and Purgatory may be solid best for first chairs (3-7 early with more during the day). The winds shift on Saturday to the NW cranking out some snow over the I-70 corridor (Heavy convection with a cold front may land several inches in short duration late Saturday morning or early PM). Snow will also be falling in the central mountains (Monarch could score) extending into northern New Mexico under NW flow (Thats good for Taos). Northerly upslope winds are likely Saturday PM into Sunday so the front range corridor near Denver, Winter Park, Berthoud Pass and Loveland are likely to see decent amounts for Sunday morning. I would chase west and south for Saturday (Crested Butte, Aspen, Wolf Creek, Silverton) and north along I-70 late Saturday or early Sunday. Its impossible to nail down the deepest amounts with so man wind shifts and terrain focussed variables. An early guess is 5-11 inches for the southern San Juans, 6-8 Aspen, and 4-8 inches along the I-70 corridor by late Saturday. As NW or North flow kicks in Saturday night its possible resorts closer to Denver see higher amounts for 1st tracks Sunday. Chase from the San Juans back to Denver on Saturday PM. Someone near Denver will report decent numbers from late Saturday to early Sunday.
More snow Is moving into the far West late this weekend into early next week. That will be addressed in a future post. Some will be significant especially for the Sierra, Oregon, and Washington. The Rockies should grab respectable leftovers.
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