Posted May 7, 6:39 am MT 5:39 PT
Snow Stake Cams
MSLP Surface Chart thru May 12
All Snow
3 Day Total Snowfall West Coast
5 Day Total Snowfall Rocky Mountains
Forecast Discussion
We are tracking the storm that we hope will be a repeat of last year’s May 21st dump in Colorado. I would be nice to get it earlier in May while we still have most of Arapahoe Basin open. The timing on this storm is becoming 
clearer, and the strength is weakening, but there is still a lot of time for this storm to fall apart or gain strength.
Looking at the most recent 500 mb chart, you can see the trough forming with some decent vorticity (red) centered in Colorado. When you compare that chart to the cycles that preceded this upcoming storm, you can see that it most resembles the first chart (below). That storm did produce double digit totals for A-Basin, Aspen, Telluride and Wolf Creek.
Thursday System Last 4 Cycles
This storm is completely cut-off from the jet stream, which is consistent with the past 4 cycles. Below is the projected jet stream map for Thursday. You can see the jet stream is flowing around a rather large Low-pressure system in the Gulf of Alaska, stays in Canada and flows around another Low-pressure system south of Greenland.
Timeline
This is a slow-moving storm that will hit the Pacific Northwest in the afternoon tomorrow and spin its way down the coast reaching Lake Tahoe late Tuesday night. There is not much moisture in the system for the West Coast or Utah which can be observed on these Euro ensemble charts, for Lake Tahoe and Alta, below (click to enlarge).
Once the storm passes Utah, it picks up moisture, from the Gulf, on its way to Colorado, that will likely produce thunderstorms for Denver and the front range. Check out the chart for Aspen–a lot of potential moisture, but presently about 0.4 tenths of an inch, which would be in the 4-8 range. The storm hits Colorado Wednesday night, which is good timing for the coldest air.
More on this tomorrow and I am just about finished with the next cycle comparison video.
May 21st Last Year
Open Resorts
California
Palisades, Heavenly, Mammoth
Utah
Snowbird, Solitude and Park City
Colorado
Breckenridge, Arapahoe Basin, Copper Mountain, Winter Park
Forecasted Areas
Pacific Northwest Cascade Mountains
Crystal Mountain, Mount Hood Meadows, Timberline, 49 Degrees North, Bachelor, Mt Baker,
Lake Tahoe Sierra Mountains
Heavenly, Palisades Tahoe, Kirkwood, Dodge Ridge, Donner Ski Ranch
Utah Wasatch Mountains
Alta, Park City, Deer Valley, Brighton, Snowbird, Brian Head
Colorado Rocky Mountains
Aspen, Aspen Highlands, Snowmass, Vail, Beaver Creek, Winter Park, Keystone, Arapahoe Basin, Breckenridge, Copper Mountain, Powderhorn, Ski Cooper, Telluride, Crested Butte, Silverton, Wolf Creek, Eldora, Loveland
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