A powerful storm system approaching from the northwest will bring significant snow to Jackson Hole and the Tetons from Tuesday night (New Year’s Eve) through Wednesday (New Year’s Day) and into Wednesday night. Skiers and snowboarders can expect a powder day to ring in the new decade on Wednesday.
The National Weather Service in Riverton has issued a Winter Storm Warning for all of Teton County, valid from 11 pm Tuesday through 5 am Thursday. Here is a map showing the current National Weather Service advisories across the region.
As of Tuesday morning, moisture is already arriving ahead of the main system, leading to overcast skies and occasional snow flurries. More of the same can be expected throughout the day Tuesday. A current look at relative humidity values at 10,000 ft. of elevation shows some leading-edge moisture reaching Northwest Wyoming, with the bulk of the moisture approaching from the northwest, which will arrive in Jackson Hole Tuesday night.
Widespread snow looks to arrive around 9-10 pm Tuesday night and continue through Wednesday night, with the heaviest snowfall rates occurring from early Wednesday morning through Wednesday afternoon. Total snow amounts from Tuesday night through Wednesday night will range from 10-18″ in the Tetons and 5-9″ in the Jackson Hole Valley.
The jet stream will be oriented in a favorable position from northwest to southeast into Wyoming, which will help to enhance snowfall rates.
All-day Wednesday is going to offer great powder skiing conditions, but also rising avalanche danger for backcountry users. For travelers, difficult driving conditions should be expected on the highways and over Teton and Togwotee Passes on Wednesday morning, Wednesday evening, and Thursday morning.
Temperatures will gradually moderate as this storm arrives, following another frigid start Tuesday morning. In the valley, highs will rise into the teens on Tuesday afternoon, before slowly rising into the low 20s Wednesday morning and into the upper 20s for highs Wednesday afternoon.
In the mountains at 9,000 feet, temperatures will generally remain steady in the teens both Tuesday and Wednesday. Mountain winds will increase out of the west at 20-30 mph with gusts to 40-45 mph during the day Wednesday, before shifting to northwesterly at 15-25 mph with gusts to 35 mph Wednesday night. Valley winds will be out of the southwest at 5-15 mph with gusts to 20 mph for most of this event.
The map below from the Colorado Avalanche Center’s weather model shows projected snowfall amounts across the Western US through 6 am Thursday. The northwest to southeast storm track is evident here. In addition to Jackson Hole, much of Idaho, Western Montana, Northern Utah, and Western Colorado will do well with this storm.
The main storm will exit the area early Thursday morning, but lingering moisture will result in additional light snow on Thursday and Thursday night with additional snow amounts of 2-4″ in the Tetons and a trace to 1″ in the valley. Temperatures will also be colder on Thursday with highs in the mid 20s in the valley and in the single digits at 9,000 feet. An active pattern will continue through the weekend with additional snow expected each day Friday through Monday.
Happy New Year!
Alan Smith, meteorologist
3923 LONG VIEW LANE Jackson
2901 EGBERT AVE Tetonia
167 W CENTER STREET Victor
8570 CREEK CROSSING LP Jackson
654 TURTLE WALK Victor
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