JACKSON, Wyo. – Following several days of mild and sunny weather, a weak storm will arrive on Friday with snow levels up around 9,000 feet. Another storm will bring rain and snow showers from Sunday to Tuesday, but snow levels will only gradually come down with rain falling across the lower elevations.
Recent Weather Pattern
Last week, a series of weak storms brought snow to the Tetons and light rain to the lower elevations.
From November 6-8, the southern and eastern side of the Tetons above 8,000 feet picked up 7-11 inches of snowfall, while totals were lighter on the western side with 4 inches at Targhee.
Light rain fell across the lower elevations, but this storm cycle was mostly orographically driven (terrain-enhanced precipitation), so Jackson only received 0.16 inches of rain over 3 days, and Driggs only 0.04 inches.
Rain briefly changed to snow in Jackson on Friday evening as a cold front moved through, but did not accumulate.
Since this storm, we had a seasonally chilly day on Saturday, and temperatures have progressively warmed up since then. A high of 58 was recorded in Jackson on Tuesday afternoon, and again on Wednesday afternoon (the latter is not reflected in the table below).
The average high and low in Jackson on November 12 are 43º and 19º for perspective.
In the mountains, temperatures have risen into the 40s each day since Sunday, and snow coverage is sparse except in shaded, wind-loaded, or north-facing terrain above 9,000 feet.
So far in November, temperatures are running 6.8 degrees above normal in Jackson.
Upcoming Weather Pattern
We do have a more active weather pattern ahead, but it’s going to take some time for the stubborn warm airmass to break down and give way to more winter-like conditions.
First, we will have one more mild and sunny day on Thursday with highs in the upper 50s. If you’re looking for one more day to soak up these relatively warm conditions, this will be your day to get out and enjoy.
On Friday, a weak storm will move through, bringing rain and snow showers to the area, mainly during the daytime hours. Snow levels (i.e. the rain/snow line) will be unseasonably high for this time of year, up around 9,000 feet to even 9,500 feet, and valleys will see temperatures reach the 50s once again.
On Saturday, a break is expected in between storms, but we will see mostly cloudy skies (mid-level cloud cover, obscuring the peaks at times) with highs near 50 in the valley.
The next storm will also be somewhat weak and disorganized, but it will be a longer-duration system that will come through with multiple waves of showers from roughly Sunday through Tuesday.
Warm air will lead to primarily a rain event in the valley with snow levels starting out around 8,000-9,000 feet on Sunday before gradually lowering on Monday and Tuesday.
There is greater uncertainty with how cold it will get toward the end of the system on Tuesday and how far snow levels will drop.
There is a chance that this system could end with some brief light snow in the valley, but it’s far from a guarantee. For most of the event, snow levels are currently projected to be 7,500 feet or higher.
The image below from the European Ensemble Model shows temperature anomalies in the lower atmosphere across the country. This gives us a good idea of how anomalous the warmth is that we’re experiencing right now.
We could actually see some decent snow accumulations add up over time across the higher terrain over the next week, but it will mainly be confined to areas above 9,000 feet, with low to mid elevation terrain still struggling to develop a snowpack.
Looking further out, beyond November 19, confidence is growing that we will head into a colder pattern late in the month, and it should finally start to feel like winter around here.
NOAA’s 8-14 Day Outlook favors below-average temperatures and above-average precipitation.
While the details of any potential storms are highly uncertain this far out, the outlook for skiers and riders is more favorable heading into late November once we get through another week of unseasonable warmth.
Alan Smith, Meteorologist
