A wave of snow is moving through the Tetons on Wed AM with a nice refresher expected. A stronger storm will impact the area from Thursday afternoon through Friday morning with significant snowfall expected. Friday looks like a nice powder day. More snow is possible Sun (Dec 4) to Tue (Dec 6) but we'll be right on the fringe of the storm track & confidence is low due to poor model agreement.
Short Term Forecast
Forecast for Wednesday - Wednesday Night:
New snow totals as of early Wednesday AM include 2 inches at Grand Targhee and JHMR's upper mountain and 1 inch at JHMR's mid-mountain.
A strong storm is currently impacting the Pacific Northwest, while a leading edge disturbance is moving into the Tetons on Wednesday morning, resulting in a nice round of snow. Here is the radar image from about 7:28 am Wednesday morning,
Most of the snow associated with this feature will fall through about midday on Wednesday. After that, the best dynamics and moisture are likely to shift just north of the area into Yellowstone, which should result in a decrease in snowfall (occasional light snow showers/flurries) heading into Wednesday afternoon and Wednesday night.
Snow Totals: I'll go with 2-4 inches in the Tetons above 8k and a half-inch to 2 inches in the valley on Wednesday.
A minority of models are keeping the band of snow over the Tetons later into the afternoon and early evening on Wednesday. While this is a less likely solution, if snow were to persist for longer in the day/evening than expected, then I wouldn't rule out 6+ inches in the Tetons (lower probability "boom" scenario).
Forecast for Thursday - Friday:
A strong storm remains on track to bring significant snowfall to the Tetons late this week. Thursday morning will start out relatively dry but with flurries/light snow showers possible. Snowfall will then become more widespread on Thursday afternoon, with heavy snowfall rates expected through the overnight hours on Thursday night.
Most of the snow associated with this storm will have accumulated by daybreak on Friday morning, but additional snow showers on the backside of the storm will continue through midday Friday.
Wind: Mountaintop winds will be out of the southwest for the bulk of this event, and winds will be very strong on Thursday night with gusts to 50-70 mph possible above 9,000 feet. A cold front will move through early Friday morning (predawn), and winds will remain brisk out of the west behind the front throughout the day on Friday with gusts in the 35-45 mph range.
Temperature Trends and Snow Density: Warmer air arriving with this storm will result in higher-density snow quality compared to the last storm with snow-liquid ratios of around 11:1 through the heaviest part of the event. However, much colder air will arrive behind the early Friday AM cold front, and this will result in a transition to low-density snowfall on the backside of the storm Friday morning.
I'm sticking with a snow forecast of 7-14 inches for the Tetons above 8,000 feet from Thursday morning through about midday Friday. For the Jackson Hole Valley, I'll also stick with a forecast of 3-7 inches. Further east, Togwotee Pass should end up in the 4-10 inch range.
Thursday could be a sneaky fun day on the slopes as the storm gets underway prior to the Friday powder rush since we'll be on day 5 in a row of new snow.
Friday will certainly offer the deepest conditions, especially during the morning hours. Keep in mind that early season conditions still exist, and if you head into the backcountry, expect elevated avalanche danger and make sure you tune into the Bridger-Teton Avalanche Center for daily avalanche forecasts.
Teton Pass Travel Conditions:
Winter conditions will continue over the pass and in the valleys on Wednesday with the snowiest conditions and lowest visibility expected during the first half of the day. Wednesday afternoon and Thursday morning will be wintry but manageable ahead of the next storm.
Travel conditions will quickly deteriorate from Thursday afternoon through Friday morning with heavy snow, strong winds, blowing snow, and poor visibility expected both over the pass and over open valley roads. Avalanche control is also a possibility early Friday morning.
Improving conditions are expected on Friday afternoon, but gusty winds will continue to result in areas of blowing snow.
A break in the action is expected on Saturday. After that, we have two storms that will be pushing into the Western U.S. between Sunday (Dec 4) and Tuesday (Dec 6). The first storm on Dec 4-5 will be passing south of the area and we will be right on the northern edge. The second storm on Dec 5-6 will be passing north of the area and we will be right on the southern edge.
Models are in poor agreement on the storm tracks of both of these storms, so I have very low confidence in how things will play out. However, I can say that there is a chance of snow each day from Sunday (Dec 4) through Tuesday (Dec 6), but it's not a great-looking setup for us so I'm only expecting light snow for now.
Looking further out, we will likely see a break at least on Wednesday (Dec 7), then it's possible we could see a storm sometime in the December 8th-10th timeframe.
Confidence is low in how the pattern will set up heading into mid-December. The European and Canadian Models look a bit more favorable in keeping the storm door open to some extent with continued below-average temperatures. The American GFS is trending toward a somewhat warmer/drier period, at least temporarily, but this is an outlier at the moment.
Thanks so much for reading! Next update on Thursday (12/1).