A significant storm remains on track to hit the Tetons over the next few days with heavy snow expected from Thursday afternoon through Sunday morning. Snow quality will be low-density blower pow with the deepest totals favoring the higher elevations in the core of the Tetons as well as the west side including Targhee. Friday & Saturday will be the deepest days on the slopes w/Sunday leftovers.
Short Term Forecast
Targhee picked up another 2-3 inches on Wednesday, bringing 2-day totals to 9-10 inches (measurements made at Chief Joe Bowl and Targhee Snotel plots). Only a trace of snow was reported at JHMR.
This mid-week snow was a nice appetizer for what's to come over the next 3-4 days.
Forecast for Thursday to Sunday
A major storm cycle remains on track with some slight adjustments to the timing. I'm now expecting heavier snow to develop at the onset on Thursday afternoon and Thursday night, while the event also is trending toward an earlier finish on Sunday morning. I'm still expecting the heaviest snowfall rates on Friday-Friday night.
Timing-wise, snow will begin on Thursday afternoon with snowfall rates steadily increasing through Thursday night with steering winds aloft out of the northwest.
Northwest flow continues on Friday and Friday night with snowfall rates picking up substantially. 1-2+ inch/hour rates are expected at times across the higher terrain and western slopes.
Steady moderate to at times heavy snow will continue during the day on Saturday with west/northwest winds aloft. Snowfall rates will not be as heavy compared to Friday, but it will still keep snowing.
Snow will continue on Saturday night with steering winds aloft shifting to west/southwest and eventually southwest before coming to an end sometime on Sunday morning.
I'm upping my storm total snow forecast for the Tetons to 1.5 to 3 feet (18-36 inches) from Thursday afternoon through midday Sunday. I'm expecting Targhee to receive the deepest totals under a west/northwest flow.
For the lower elevations, Teton Valley will see the deepest totals ranging from 9-18 inches, while the Jackson Hole Valley will see 5-12 inches, with the highest totals for the JH Valley favoring areas west of the Snake River and north of the airport.
For Togwotee Pass, I think we'll end up somewhere in the 10-24 inch range.
Here is my daily breakdown for 24-hour periods ending at 5am each morning over the next 4 days:
Here are graphical snowfall projections using a blend of weather models:
In addition to the Tetons, I'm expecting deep snow totals in the Snake River Range, Salt River Range, and Beartooths/Absarokas. The Bighorn Range should also do very well, especially the north side. The Wind River Range will see good but not crazy high totals as they tend to do better with southwest winds than northwest winds.
For Star Valley, I'm also expecting deep totals, especially around Alpine where 1 to 2 feet is possible.
Snow Density and Temperature
Cold air in place will result in a dry and powdery snow event with snow-liquid ratios likely to be around 15 to 1 for most of the event (5% density).
Temperatures at 9,000 feet will be in the low/mid teens from Thurdsay afternoon through Friday evening during the heaviest part of the event, then will trend lower into the upper single digits on Saturday and mid single digits by the time snow tapers off on Sunday morning.
Valley temperatures will range from the upper teens to mid/upper 20s through this event by day and night before trending colder on Sunday.
Winds above 9,000 feet will be out of the west/northwest on Thursday and Friday at 15-25 mph with gusts to 35-45 mph. On Friday night and Saturday, winds will be westerly and will decrease to 10-15 mph with gusts to 20 mph.
Similar wind speeds are expected on Saturday night but with a shift to southwest winds. Winds will become light and variable on Sunday.
Valley winds will be strongest on Thursday night and Friday out of the southwest at 10-20 mph with gusts to 25 mph, before decreasing to 5-15 mph on Friday night and Saturday.
Friday is looking incredible with deep snow totals already expected by the time lifts start spinning and heavy snowfall rates expected throughout the daytime period. Gusty winds and reduced visibility will make for a legit storm skiing day.
Saturday is also going to be deep, especially in the morning, but with additional refills expected throughout the day. Visibility will remain limited but winds will be lighter compared to Friday.
Sunday will also offer plenty of leftovers but will not be as deep as Friday or Saturday as the storm will be ending. Visibility may start to improve somewhat by Sunday afternoon, but I'm not totally confident in that yet.
Rough travel can be expected starting on Thursday afternoon/evening, with the most severe conditions expected throughout the day on Friday and Friday night with heavy snowfall rates, low visibility, and areas of blowing and drifting snow.
Conditions will be worst over Teton Pass, along the open valley roads on the Idaho side, and through the Snake River Canyon, but the JH Valley will be no cakewalk for driving either.
Travel conditions will remain slow on Saturday with snowpacked roads and areas of blowing snow, but not as severe as Saturday. Gradual improvement will then continue on Sunday.
Once we get beyond the weekend storm, I'm feeling less optimistic about the medium/long range outlook for the end of January and through the first 10 days or so of February. Models have been trending toward a less active pattern across the West during early February with high pressure making more frequent appearances.
From Monday (Jan 30) through Thursday (Feb 2), I'm expecting cold and dry conditions as modified arctic air spills into the area behind the weekend storm. Inversions are also likely to set up with the coldest temps in the valley.
After that, I'm seeing hints of 2 potential storms during the Feb 3rd-7th timeframe, but overall the pattern is trending less favorable for strong storms/significant snow. After the 7th, confidence is low but the latest long-range model runs are hinting at high pressure rebuilding over the West.
Thanks so much for reading! Next update on Friday (Jan 27).