JACKSON, Wyo. – April has been a quiet month so far with dry conditions and relatively mild temperatures. However, we will see some typical spring ups-and-downs over the next week, including a shot of cold air and snow showers on Thursday.
Recent Weather Conditions
As of Wednesday, we have had seven consecutive days without measurable precipitation in the town of Jackson while the Tetons only received very light precipitation on Saturday.
Jackson has only received 0.16 inches of precipitation and a trace o snow so far in April, while the Tetons above 8,000 feet have received 6-12 inches of snow so far this month, nearly all of which fell during the first three days of the month.
Although we are only halfway through the month, for perspective, the town of Jackson averages 1.61 inches of precipitation in the month of April and the Rendezvous Bowl Plot at 9,580 feet in the Tetons averages 59 inches of snowfall in the month of April.
During this dry spell, we have seen widely variable temperatures with some very warm afternoons but also some very chilly mornings.
On some days, we have seen 40 to 50 degree temperature swings between high and low temperatures in the town of Jackson, which is more reminiscent of late summer and fall when conditions are drier. Diurnal temperature swings are usually lower at this time of year.
Last week, the high temperature hit 70ºF in Jackson on Friday, which was the first time since 2020 that we hit 70ºF during the month of April. Also, this was the earliest in the season we have hit 70ºF since 2012.
However, a cold front moved through on Sunday and the temperature plummeted to 13ºF on Monday morning. On Tuesday and Wednesday, temperatures have warmed right back up into the 60s.
Warm temperatures and a lack of precipitation recently have resulted in snowpack melting at a faster rate than normal recently. As of April 1, snowpack in the Snake River Headwaters Basin was 111% of average. However, as of April 16, we are at 99% of average – still a healthy snowpack, but decreasing quickly.
In the chart below, the black line shows this year’s snowpack as measured by snow water equivalent and the green line shows the average value.
Upcoming Weather Pattern
A shock to the system is coming on Thursday as a storm system arrives along with colder air.
A cold front will slowly push in from the north and northeast on Thursday with snow showers developing on Thursday morning and continuing through early Thursday evening.
Snowfall will be showery in nature with the potential for high variation in snowfall amounts over short distances, but most locations in the Tetons above 7,500 feet should pick up at least a few inches of snow with travel impacts likely over Teton Pass.
Snowfall amounts will be heavier across Central and Eastern Wyoming due to favorable northeast winds.
The Jackson Hole Valley will see wet snow mixed with rain at times on Thursday with snow struggling to accumulate for most of the day. Highs will reach the upper 30s to low 40s in the valley, which will be a 20-25 degree difference versus Tuesday and Wednesday.
However, the valley could pick up some light accumulations by early Thursday evening as the cold front moves through and temperatures drop.
This storm will be the main weather feature across the Western U.S. over the next week, with areas near and east of the Continental Divide in Montana and Wyoming, as well as much of Utah and Colorado, favored for the heaviest snowfall amounts.
Behind Thursday’s storm, a lull in the pattern is expected with partly cloudy skies and chilly temperatures on Friday giving way to sunshine and warmer temperatures on Saturday with highs in the low 50s.
Another weaker storm system is expected on Sunday and Monday with mountain snow showers, cooler temperatures, and a mix of rain and snow showers in the valley.
A gradual warming trend is expected heading into the middle of next week, but occasional showers will remain possible.
Beyond April 23 (7+ days out), temperatures are expected to generally trend upwards back to above-normal levels. Average highs in late April are in the low to mid 50s for perspective.
The big-picture weather pattern will also favor frequent weak systems, rain and snow showers, and higher average snow levels (rain/snow line).
Alan Smith, Meteorologist
