Jackson Hole Daily Snow

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By Alan Smith, Meteorologist Posted 10 months ago May 22, 2023

Decreasing Smoke, Increasing Showers & Thunderstorms

Summary

Lingering smoke from Canadian wildfires will clear out early this week as winds shift to southwest. This southwest flow (courtesy of a persistent trough of low pressure along the West Coast) will lead to an uptick in moisture, resulting in near daily showers & t-storms for at least the next week with the potential for decent rainfall amounts over time. Temps will also remain on the milder side.

Short Term Forecast

Smoke Outlook:

Smoke lingered across the area throughout the weekend, though not as heavy compared to Thursday and early Friday. Air quality index (AQI) values were in the "Moderate" range over the course of the weekend.

On Monday morning, we are seeing a shift from a northerly flow to a west/southwest flow with haze and moderate air quality remaining over the area early in the day. You can clearly see the "haziness" from the Jackson Hole Golf & Tennis webcam looking at the Tetons.

The good news is that the smoke will soon be on its way out as west/southwest winds eventually shift the smoke plume to our east.

Check out the smoke forecast on Monday AM (first picture) compared to the smoke forecast for Monday evening (second picture).

Once this smoke clears out, I don't expect it to be an issue again for the foreseeable future as a consistent southwest flow sets up over our area. 

Weather Outlook – Big Picture:

As the smoke clears out, we are also about to head into an active pattern. First, a trough of low pressure will pass north of our area on Monday. Although the highest impacts from this first system will be located over Montana, we will still see increasing instability and thunderstorm chances compared to prior days.

The pattern will then turn more active from Tuesday on as a persistent trough of low pressure sets up along the West Coast, placing us under a southwest flow with embedded disturbances (known as shortwaves) arriving on a near-daily basis. The result will be a noticeable uptick in showers and thunderstorms.

Despite the wetter pattern, a ridge of high pressure to our east and a lack of any major cold fronts associated with the trough to our west will keep temperatures on the milder side. The milder temperatures will also support greater instability and higher thunderstorm/lightning potential.

Average highs in Jackson at this time of year are in the mid 60s. Highs will reach the mid 70s in Jackson on Monday, and then will reach the mid 60s to low 70s each day from Tuesday through the holiday weekend depending on cloud cover.

Forecast for Monday:

Our airmass will become unstable on Monday afternoon as temperatures in the upper atmosphere cool in response to the trough passing north of the area, while abundant sunshine will heat up the lower atmosphere. As a result, thunderstorms are likely to develop across the higher elevations on Monday afternoon.

Wind shear (change in winds with altitude) will be weak on Monday, and as a result, storms will be isolated in coverage. These will be "pulse" type storms that will be fairly short-lived, but with new storms developing as the old ones fall apart. Storms will produce light rainfall, but cloud-to-ground lightning will be a threat.

Storm motions on Monday will be to the east/northeast at 10-20 mph, and while the best chance of lightning will be over the higher terrain, we could see some storms drift into the valleys as well.

Forecast for Tuesday:

A more active day is expected on Tuesday as a stronger disturbance moves into Western Wyoming from the southwest. Wind shear will also be greater, resulting in more organized and widespread clusters of showers and thunderstorms, possibly starting as early as midday to early afternoon.

Showers and storms on Tuesday will move from southwest to northeast at 10-20 mph and will be capable of producing cloud-to-ground lightning, small hail, gusty winds, and locally heavy downpours. Multiple rounds of showers/storms are also likely during the afternoon and into the evening.

Rainfall is always hit-or-miss in these setups, even when storm coverage is expected to be more numerous. However, stronger thunderstorms or training of storms (multiple storms that track over the same areas) will be capable of producing localized rainfall amounts of 0.3 to 0.7 inches.

While moisture levels do not look impressive enough for a true flash flooding threat, the potential for soaking rains along with snowmelt-swollen creeks/streams could potentially pose a threat for localized stream flooding depending on if and where heavier thunderstorms occur. 

Forecast for Wednesday:

A fairly similar setup will remain in place on Wednesday with another shortwave disturbance expected to move through from the southwest. As a result, showers and thunderstorms are likely to develop across the Greater Teton/Yellowstone Region once again during the afternoon and evening hours with locally heavy (but brief) downpours possible.

Stronger thunderstorms or training of thunderstorms on Wednesday will be capable of producing localized rainfall amounts of 0.2 to 0.5 inches. 

Throughout this pattern over the next three days, the best chance of rain and lightning will occur during the afternoon and evening hours, but there is a slight chance of showers during the overnight and morning hours as well.

Also, snow levels will be high during this pattern with the mild airmass in place, generally 11,000-12,000+ feet. As a result, any new snowfall will only occur over the highest peaks, possibly mixing briefly lower at times during heavier showers. 

Here is my 3-day lightning outlook:

If you're new or need a refresher to OpenSnow summer features, be sure to use the following features and map overlays to track showers and thunderstorms:

Daily and Hourly Weather Forecast

Current Radar

Forecast Radar

Current Lightning Density

Extended Forecast

Outlook for Thursday through Memorial Day Weekend and Beyond:

It's looking like a rinse-and-repeat pattern will continue late this week and into the holiday weekend as a persistent southwest flow remains over the area.

The result will be daily chances of showers and thunderstorms while no significant changes in temperatures are expected with highs ranging from the mid 60s to low 70s in the valleys depending on cloud cover. Overnight lows will also be milder with more abundant moisture in place.

I certainly wouldn't let the forecast ruin your plans for getting outside, but you'll want to pack a rain jacket. Also, the best chances of staying dry will generally be during the morning hours with higher chances of rain and lightning during the afternoon and evening hours.

Thanks so much for reading! Next update on Wednesday (May 24).

Alan Smith 

About Our Forecaster

Alan Smith

Meteorologist

Alan Smith received a B.S. in Meteorology from Metropolitan State University of Denver and has been working in the private sector since 2013. When he’s not watching the weather from the office, Alan loves to spend time outdoors skiing, hiking, and mountain biking, and of course keeping an eye on the sky for weather changes while recreating.

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