JACKSON, Wyo. – The first week of May has been anything but spring-like in Jackson Hole with well-below-average temperatures along with significant late-season snowfall. Even the town of Jackson has seen accumulating snowfall. We will finally head into a more seasonable pattern this weekend and next week with highs well into the 60s.
Recent Weather and Impressive May Snow Totals
Winter rarely exits quietly in Northwest Wyoming, and after a relatively tame April, winter came back for one last laugh during the first week of May. High temperatures have been running about 20 degrees below average for most of the past week, and snowfall has been significant.
Since last Wednesday, there have been two impressive storms. The first one was short-lived but occurred during the early morning hours of Friday, May 13.
This storm featured a relatively narrow band of heavy snow that developed when a wind convergence boundary set up over Teton County overnight, resulting in heavy snow not only for the Tetons but also for the Lower Jackson Hole Valley.
Snowfall totals in the Tetons ranged from 4-8 inches during this event, while the town of Jackson picked up 5-6 inches of snowfall during the early morning hours – the heaviest May snow event in town since 2013.
For perspective, the town of Jackson only averages 0.6 inches of snow accumulation during the month of May, so 5-6 inches this late in the season is impressive. The official climate station in North Jackson near the Elk Refuge reported 5 inches.
It’s tough for the town of Jackson to see significant snow accumulations in May, and typically only occurs when snow is falling at a heavy rate (1″/hour or higher) during the overnight hours due to the amount of solar radiation we see at this time of year (even when it’s cloudy) and the fact that the ground is warmer.
We saw a brief reprieve in the weather pattern on Saturday with warmer temperatures and dry conditions. Then, a long-duration storm impacted the area from Sunday through Wednesday, bringing substantial snow to the Tetons above 8,000 feet with additional brief light accumulations in the valley.
Snow levels started out near the top of Teton Pass on Sunday with rain falling in the valley. We also saw the first widespread thunderstorms of the season over the Tetons on Sunday afternoon.
A cold airmass settled into the area on Monday, with heavy snow falling from Monday through Tuesday. Snow fell consistently in the valley as well (mixed with graupel and rain at times), but accumulations were generally light and confined to the overnight hours.
Snow totals during this storm ranged from 1-2 feet in the Tetons above 8,000 feet and backcountry skiers have been out making turns on the pass.
Since the beginning of May, areas above 8,000 feet in the Tetons have picked up a total of 2-3 feet snow, which is impressive for this time of year!
The Rendezvous Bowl Plot at Jackson Hole Mountain Resort (which is closed for the season, but still measures snowfall) has received 35 inches of snow already in May, compared to a monthly average of 30 inches.
The town of Jackson picked up another 1-2 inches of total snowfall during this most recent cycle, with melting occurring between light accumulation periods.
So far, the climate station in Jackson has received 6.6 inches of snow this month, which is the fourth-highest May snow total on record, but there are a couple of caveats. First, a report has not been issued yet for Wednesday, with the potential for another half-inch to one-inch to be added to this total.
And second, there are many years in the past with missing data, so it’s possible there could be some snowier Mays in the past that haven’t been accounted for.
With these caveats aside, here is how this May stacks up…
Snowiest Mays on Record in the Town of Jackson:
- 1942 – 14.5″
- 1973 – 8.0″
- 1988 – 7.0″
- 2024 – 6.6″
- 2013 – 5.1″
In terms of mountain snowpack, we saw a steep decline in mid to late April due to melting. However, we have actually had a net gain in the snowpack over the past week and are now 108% of average (compared to 90% of average at this time last week).
As a result, we are back on track toward a fairly normal melt season, though warm and dry weather ahead could potentially lead to an eventual return of above-average melting rates.
Upcoming Weather Pattern
Are you sick of winter yet? (I suspect this question will have a mixed response in a place like Jackson).
If so, then you are in luck, because beautiful sunny weather is right on our doorstep!
Thursday will be a transition day as the storm system exits our area to the east. We will begin to warm up with more abundant sunshine and highs in the 50s, but strong east/northeast winds will develop and a rogue light shower or two couldn’t entirely be ruled out.
Friday is when our pattern will really start to shift as a ridge of high pressure builds over the Western U.S. This will signal the transition to a warmer and drier weather pattern.
From Friday through Sunday, high temperatures will warm up well into 60s under mostly sunny skies (low 60s on Friday, upper 60s by Sunday). Average highs in Jackson in May are in the low 60s, so this is a fairly seasonal pattern temperature-wise.
Next week, a mild pattern will continue with temperatures running slightly above average, which means highs in the mid to upper 60s most days. Our first 70-degree day of the season is not out of the question either (our average first 70-degree day is in early May, so we are a little behind schedule this year).
There is a chance we could see an occasional disturbance sneak in from the northwest next week, resulting in a chance of light showers. However, significant precipitation is unlikely with this pattern looking more dry than wet.
Alan Smith, Meteorologist
