Summary: Updated snowfall totals for 3 systems we are watching from Thursday to early next week. You could chase from the Sierra to the PNW/BC, and finish in the northern Rockies. There are some red flags with these storms (Winds, Snow levels) but overall many areas will nab from 10-28 inches. Some deeper spots might be found in the Sierra, and western BC (Whistler summit).
Get the powder now, as high pressure takes firm grip from mid next week through the holiday period with a warming trend.
Sierra:
When looking for your best powder options, I will stick to the Sierra for the colder storm on Thursday (Today). Winds will be gusty, so it's possible that some upper lifts might not spin. Expect widespread totals of 5-9 inches along the Sierra Crest and 3-6 inches on the eastern side of Lake Tahoe. Snow levels will be lake-level. Storm #2 is wetter and windier and is due on Saturday. This will bring warmer air and raise snow levels that start at 7,000 feet and eventually fall to lake level later Saturday to Sunday. Winds will be cranking, and many lift closures will be evident at upper elevations (This might not be an ultimate chase). Winds decrease on Sunday in the Sierra with lower-density powder from Saturday night (Better chase day). Totals from the weekend storm will likely be in the 10-17 inch range at upper elevations and 5-10 inches mid-mountain. There is some model discrepancy on who nabs the highest totals (South or North Sierra). Amounts might be variable depending on which model wins (North or south).
Below: Storm #2 is due this weekend for the Sierra, with significant snow above 7,000 feet. Mono County (Mammoth) likely comes up with lower numbers. The Canadian model on the left pushes the highest totals south of Lake Tahoe, while the European on the right moves the heaviest snow north.
Below: University of Utah ensembles for Palisades showing the first storm (7-9 inches) in the Dec 12/13 range, with the second surging totals to near 20 inches by later this weekend (December 15). A third and weaker wave hits the Sierra early next week (You can see the final bump in snow totals).
PNW -BC Chases
The PNW will grab abundant snowfall this weekend, especially in western BC. By Saturday mid-morning, the models have trended the highest amounts for the northern Cascades of Washington from Mt Baker, predominantly north to Whistler (5-11 for Baker and 10-15 for Whistler). Further south, it's likely that 4-8 inches await your first tracks above 4,000 feet at Crystal, Stevens, and perhaps the northern Oregon Cascades. Snow will continue on Saturday, with additional amounts in all areas. Western BC might win the game with totals above 5000 feet in the 12-20 inch range.
The Good: Plenty of moisture for the PNW, especially in northern regions of Washington and most of the highest elevations of western BC. Colder air improves snow quality by mid or late Saturday into Sunday. The Bad: Temps are warm, with the first moisture surge occurring Friday night/early Saturday. Rain might be falling below 3500. Cold air on the Cascades (Mission Ridge) interior will keep temps hovering near freezing at the bases of many ski areas in Washington. This cold air is not evident in Oregon, so snow levels are higher (4500). Winds will be strong, especially in the northern regions of Washington and southern BC, on Saturday (Higher peaks at Whistler will likely remain closed).
Below: The University of Utah ensembles are showing an average (Dark lines) of up to 10 inches at Stevens Pass by Saturday midday (December 14), with snow continuing to build into next week.
Below: Saturday morning, 4800-foot temps in the PNW are above freezing in Oregon. The colder temperatures in the interior of Washington keep the ski areas slightly colder (-1 or -2 at 4800), pushing snow levels lower (3500). Canada also stays somewhat cooler, but rain will fall at lower elevations at Whistler.
Below: Isolated pockets of strong winds were noted from Friday night to Saturday afternoon, stretching from the Sierra to the northern PNW and western BC. On Saturday, you can see both sections of strong winds splitting north to Whistler.
Idaho and Rockies
The Jet stream will pass just south of Wyoming, pushing decent totals with S and SW flow into central Idaho, including Sun Valley, which often does well with this pattern (Southerly flow pushing north from the Sierra) on Saturday. Expect 6-12 inches from the McCall area mountains, Wood River Valley (Sun Valley), and north to Selkirk Powder (Saturday).
Sponsor Alert: Please check out Selkirk Powder Cat Skiing with 6200 acres of new terrain this season stretched across 3 peaks reaching 6700 feet! They should score some deep powder from the next few storms. Cat Skiing begins on January 4th.
On Saturday PM-Sunday, peak snowfall hits the Tetons, where JHMR is slightly favored for 6-12 inches. Snow density will be heavy initially with warm S SW air aloft. Colder air from Sunday PM to Monday with a wind shift to the NW will bring a final 2-4 inches of light-density powder favoring the Targhee side of the ranges. Teton Pass will also grab snowfall from this storm (5-10).
In Utah, the models upticked slightly from yesterday. Warm air aloft with SW flow from Saturday afternoon to Sunday, followed by NW flow on Sunday, should allow for good odds of 4-8 inches for the Wasatch Range. The Cottonwoods are likely to end up near 10 inches by midday Sunday. Some models show lower totals in the Tetons and higher amounts for the Wasatch. Colorado stays south of the main action with scraps this weekend. There might be more snow grazing in Colorado early next week, with low odds of significant amounts.
Below: American GFS, total snowfall through Sunday morning highlighting the Sierra, PNW, Central Idaho, Tetons, and a few spots in the Wasatch Range.
Below: The short-term NAM is advertising a more profound event for Utah, which would result in higher totals for most ski areas in the Wasatch by Sunday morning (10-15).
Below: University of Utah based on the GFS showing 2-3 inches Thursday/Friday and another 12 inches by Sunday morning. A third and lighter wave hits early next week.
Chases:
Thursday-Sierra (Low-density snow 4-9).
Saturday- Sierra (Deeper and warmer, snow and strong winds). PNW and BC (Northern Cascades might ride better than areas to the south. Strong wind issues are possible in northern regions, including Whistler). Central and north Idaho from Sandpoint to McCall and Sun Valley (Storm ski). Leftovers in Idaho Sunday.
Sunday: Tetons and Wasatch (5-11 with higher totals possible in the Cottonwoods).
EXTENDED POW
Below: Next week from Monday to Wednesday (December 18). 24-hour snowfall totals highlighting a modest event for the northern Sierra Pacific Northwest early next week. Weakening moisture overspreads the north Rockies, taking a similar path to our last few storms. Warmer temps will be noted over the west by mid-next week.
Below: You can see low pressure weakening early next week as it migrates east over the Northern Rockies (the Map is from Monday, December 16, to Wednesday, December 18). High Pressure takes hold of the west beyond this period. I don't see any significant storms until at least December 27th.
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