JACKSON, Wyo. – The coldest air of the season has taken hold this past week with lows dipping to -23ºF in Jackson and -33ºF in Driggs. However, snowfall has been minimal during the past 10 days and this trend will continue for at least another week.
Recent Weather Conditions
Arctic air has taken hold across Wyoming since last Friday. A secondary surge arrived on Sunday night, and once skies cleared overnight, we saw our coldest temperatures of the season on Monday.
Low temperatures fell into the -20s and -30s throughout Teton County (Wyoming and Idaho) and Old Faithful even hit -40º.
Air that is this cold is also very dense and sinks into mountain valleys, which is why the valleys see lower temperatures than the mountains during such events. But even so, lows fell into the minus teens at 8,000 to 10,000 feet and there was also more wind at these altitudes. Not exactly pleasant skiing conditions!
The low of -23ºF in Jackson on Monday was the coldest of this winter so far, but was not as cold as our coldest day last winter we hit -25ºF.
The high temperature on Monday only reached +1ºF in Jackson on Monday, and this was our coldest high temperature in nearly two years. Our last subzero high temperature was in late January 2023 when we saw a high of -6ºF.
Snowfall was minimal over the past week, and mainly occurred in the form of light snow showers during two events on January 17 and 19.
The event on the 17 produced 5 inches at Targhee and 1-3 inches for the remainder of the Tetons, while Jackson also picked up an inch. Very light snow also fell on January 19 with snowfall ranging from a trace to an inch.
From mid December through early January, we saw big gains in our snowpack due to frequent strong storms. However, the pattern has been much drier since the first week of January.
Snowpack in the Snake River Headwaters Basin (including the Tetons and surrounding ranges) is 83% as of January 22.
In the graph below, the current year’s snowpack is denoted by the black line, and the 30-year median snowpack is denoted by the green line. The shaded areas depict the historical minimum and maximum snowpack values, as measured by snow water equivalent.
So where has it been snowing lately? You have to look well to the south toward the Gulf Coast where a historic snow event occurred on Tuesday.
New Orleans (8 inches), Mobile (7.5 inches), and Pensacola (9 inches) obliterated their all-time snowfall records (New Orleans tripled its previous record), and Florida set a new state snowfall record with 9.8 inches measured in Milton.
There is a decent chance that some of these areas will end up with more snowfall in the month of January than the town of Jackson.
So far this month, the town of Jackson has only received 6.5 inches of snow, and opportunities for new snow through the end of the month look few and far between.
Upcoming Weather Pattern
Why has our weather been so dry lately?
A blocking ridge of high pressure has set up along the West Coast, extending northward into Alaska. This ridge has been very stubborn and has acted as a barrier to Pacific storms.
On the eastern periphery of the ridge, arctic air has spilled into the Rockies and the Central and Eastern U.S. which has supported well below average temperatures in many areas, including the Gulf Coast where unprecedented heavy snowfall (at least in modern times) fell.
This ridge will largely remain in place over the next 7-10 days, resulting in a continued dry pattern for the Tetons and Jackson Hole.
The one exception will be on Friday when the ridge will shift slightly west as a weak storm slides into Wyoming from the north. This storm will bring a round of snow showers to the Tetons but accumulations look minimal, ranging from a trace to 3 inches in the Tetons with light and spotty amounts for the valley.
Snowfall amounts will be higher east of the Continental Divide in areas such as the Bighorns.
From Saturday through mid to late next week, high pressure will rebuild, and dry conditions will return.
Temperatures will remain quite cold from late this week through the weekend. Next week, much warmer temperatures are projected in the mountains as warm air aloft pushes in from the west and south. However, a temperature inversion will likely keep cold air locked into place in the Jackson Hole Valley.
When will this dry spell end?
There are some signs of high pressure breaking down around January 31-February 1 and this looks like our next decent shot of snow. Of course, this is still more than a week away so confidence is low.
Heading into early February, there are mixed signals with long-range model projections. Some models are projecting a more active pattern to take hold, while others are projecting high pressure to rebuild over the West Coast (similar to recent weeks).
Alan Smith, Meteorologist
