Elevation dependent dumps will be happening (14-28 inches) in the Sierra this weekend. That storm pulls east, weakening somewhat and eventually tracks over north central Idaho, Wyoming, Utah and eventually Colorado by Sunday/Monday. Temps are on the warm side, so quality in the Sierra will be mank like down low and perhaps medium/heavy up top. The Pacific Northwest gets high elevation teases this weekend with a much colder system due in the extended forecast.
Chases could begin as early as Saturday for the Sierra. Snow develops Friday night above 6500 feet and will increase on Saturday (Peak). The entire Sierra Range especially along the Crest above 8,000 feet will see an excess of 20 inches by Sunday morning. Aim for higher elevation ski areas for storm skiing Saturday and additional snow into Sunday. The intensity decreases Sunday as temps begin to cool behind the bulk of moisture. Look for additional terrain openings next week. Snow amounts will vary considerably, elevation dependent. Winds will be strong Friday night into Saturday morning before decreasing somewhat late Saturday and Sunday (Lift operations may be impacted up top). Density will be on the high side so chase options are really a gamble.
For the Rockies moisture drags over Idaho (Brundage could score late Saturday/Sunday) edging south into the Wood River Valley near Sun Valley (Moderate snow). The Tetons feel the impacts Saturday night into Sunday afternoon. Amounts for the Tetons are not impressive on the Euro (4-9) but still bullish on the Canadian, GFS, and NAM. Averaging these models, my best guess is 4-7 Saturday night with another 4-7 during the day Sunday. Total amounts will range from 8-14 inches (Fairly dense snow with fairly high water content).
The Wasatch is on tap for a moderate event of 5-10 inches. The Euro is still pessimistic while the other models seem to have a wider spread. The GFS had downtrended somewhat. The NAM 12 KM shows heavy snow in the northern Wasatch (Powder) to the Idaho border (Logan - Beaver Mountain) for Sunday morning. While a general 5-10 inches is likely in most of the Wasatch there could be some upside surprises. Best day to ride powder will be Sunday (Snowing).
Colorado sees action beginning early Sunday and continuing into Monday. The models have a general trend of 4-7 inches for many resorts with an outside possibility of heavier amounts towards Crested Butte and perhaps Aspen. Some models showed an excess of 9-10 inches in some isolated areas near Gunnison. Temps with this storm are on the warm side limiting amounts and impacts in the lower Valleys. W/NW flow and colder temps will keep snow showers going into Monday morning, especially along I-70 so it's possible that Monday offers a light refresh.
Honorable Mention: The northern mountains of Montana, especially East Glacier National Park will be seeing heavy snowfall this weekend. Also, the Cascades will see some light amounts at the summits of most ski areas this weekend (More in the North Cascades). Rain will be falling at the bases. That's about to change in the extended.
Below: Total snowfall for the west ending Monday morning.
High Pressure will return to the Sierra and Rockies beyond the Monday timeframe. The ensembles show low pressure returning to the Pacific Northwest, BC, and the northern Rockies for the late week or next weekend timeframe. The operational models also show snowfall likely to return to the west favoring the Cascades (Colder temps), and sections of the northern Rockies. I am more bullish for BC, Washington, Idaho, Montana and Wyoming at this point. Still too far out to forecast with confidence.
Below: ensembles showing low pressure over the northern tier of North America by next weekend.
Below: Since the PNW has been significantly below normal on precipitation I wanted to provide some stoke of a 4 day snow map ending next Friday (December 13th) even thought it's beyond the scope of confidence. The PNW could score some decent snow in the next 5-7 days.
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