JACKSON, Wyo. – Winter has returned to the Tetons this week, as a storm on Wednesday has produced preliminary snow totals of 7.5 inches in the town of Jackson and 8-13 inches at Jackson Hole Mountain Resort as of 5:30 pm Wednesday.
Recent Weather
The first week of February was unseasonably mild and spring-like, with temperatures more reminiscent of late March or early April.
High temperatures reached the 40s or higher in Jackson during each of the first 8 days of February, and even hit 50º and 51º on Saturday and Sunday. The lower valley also lost most of its snowpack during this time.
The pattern started to change on Monday as a long-duration high pressure ridge finally broke down.
In the wake of a cold front that moved through, narrow bands of locally heavy snowfall developed across the Tetons, fueled by instability in the atmosphere. Snowfall added up to 5-9 inches in the Tetons on Monday, while the valley ended up receiving 1.5 to 2 inches on Monday evening.
Wednesday’s storm has been even more impressive as moisture arrived from the south/southwest well out ahead of a low pressure system stalled near the Bay Area of California.
Two key factors have likely favored heavy snow on Wednesday that was above what was forecast.
First, a warm front slowly moving northward stalled over the Southern Tetons for most of the day, and converging winds along this frontal boundary allowed for a fairly wide band of heavy snow to develop and remain nearly stationary for much of the day.
Second, south/southwest winds aloft have prevailed throughout the day, which has minimized the Teton shadowing effect, and has favored heavy snowfall in the Lower Valley and town of Jackson in addition to the Tetons.
As of 5:30 pm on Wednesday, the town of Jackson has received an impressive 7.5 inches of snow, while Snow King has picked up 8 inches. Also, Jackson Hole Mountain Resort has picked up 13 inches at both of its upper mountain plots and 8 inches at its mid-mountain plot.
Conditions have quickly gone from looking spring-like to winter-like in the valley.
Further north and west, snowfall has been a bit lighter at Grand Targhee, which has picked up about 6 inches of snow so far. South/southwest flow typically produces lighter snow at Targhee compared to the southern and eastern Tetons, but 6 inches is still a solid storm on top of what fell earlier this week.
Below is a 7-day weather summary for the town of Jackson. Note that the log for February 11 (today) was for the period ending at 7 a.m. An additional 5.7 inches has accumulated in Jackson since 7 a.m. for a total of 7.5 inches as of 5:30 p.m:
For perspective, the average high and low in Jackson on February 11 are 31º and 10º.
Upcoming Weather Pattern
Snow will gradually taper off on Wednesday evening, then a break in the pattern is expected from Thursday through Monday.
A low pressure system will develop well off the coast of California this weekend, but it will remain stationary for several days before moving inland, which is the reason we will stay dry for a few days.
A mix of sun and clouds can be expected during this stretch, and some occasional flurries could also fly, but no meaningful snow is expected through Monday.
Afternoon inversions are not expected in this pattern, and as a result, highs will reach the upper 30s to low 40s in the valley each day, which will lead to melting and wet/slushy conditions in town during the afternoons in the wake of Wednesday’s big snowfall.
The West Coast storm is eventually projected to move inland around the Monday night to Tuesday timeframe (roughly speaking), and this will result in our next chance of snow.
The 7-day snowfall projection below represents the average of 50 simulations of the European Model. And this projection accounts for today’s snowfall as well as the snowfall expected around Tuesday, February 17.
Looking further out, the pattern continues to look active during the second half of next week, and possibly even into the last week of February, which is great news for skiers and riders.
Alan Smith, Meteorologist
