Meteorologist Jim Woodmencey

I received a number of very cool photos from the severe thunderstorm that passed through Jackson Hole on Wednesday afternoon June 12th. Below is a collection of some of those photos. There was also another strong thunderstorm the following evening, Thursday June 13th that produced strong wind gusts and some rain, while there were no reports of hail, there was apparently some damage done by falling trees.

Both of these thunderstorms were related to a Low pressure system that was moving across the Pacific Northwest and northern Rockies mid-week. (See maps, etc. from previous blog post). A cold front associated with that Low was in the vicinity of the Idaho/Wyoming border, pretty much was a stationary front on Wednesday and then that front passed across the Tetons on Thursday evening. Most of the more intense thunderstorm activity was occurring near this front.

Thanks to all who contributed to this collection!

Thunderstorm Photos from June 12 & 13, 2013
Photo by John Hanlon	Photo by Ian Raben
Photo of Mammatus Clouds by Jim Springer from Near Jenny Lake	Zoomed in Photo by Jim Springer
Looking Southwest from Rec Center in Jackson. Photo by Darrell Miller.	From Victor Idaho on THURSDAY June 13, 2013. Photo by Susan Lykes
Hail stones down the drain! Photo by Mary Gridley	Hail Stone
Taken from the Top of Snow King Mountain

Meteorologist Jim Woodmencey

As much as I hate to sensationalize the weather, this afternoon’s thunderstorms were pretty cool to observe. Between 3:30 and 4:00 pm  a series of thunderstorms moved through the Jackson Hole area that produced hail 3/4 of an inch to one inch in diameter, measured in the Town of Jackson.

While we did not receive a lot of rain (we actually had less than 0.10 inches in Town, even with this morning’s rain), it was the size of the hail that qualified this as a “Severe” storm, by the National Weather Service definition:

“Severe Thunderstorms produce large hail, at least one inch in diameter, and/or damaging winds, at least 58 mph (50 knots).”

The best thing about today’s thunderstorms, is that they were well forecasted. My own MountainWeather Forecast for Jackson Hole had the probability of thunderstorms at 90% (rarely do I peg it at 100%!) with “Moderate” amounts of lightning, meaning several ground strikes would be likely with thunderstorms.

AND….. the National Weather Service was also right-on with this one, with the National Storm Prediction Center forecast map for the day, and the Riverton NWS Office issuing a a Special Weather Alert very early this morning warning of strong thunderstorms and dangerous  lightning, and telling people to get out of the hills and seek shelter early this afternoon. Good Work NWS!

National Forecast Map from This Morning

More Images

A selection of weather maps is cataloged below, capturing the satellite, radar, and lightning that was occurring just prior to and during this weather event. Days like this make it fun to be a weather nerd! Shouldn’t be outside anyway, so might as well look at the weather on the computer, eh?

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National Lightning Strike Map at 2:45 pm Wednesday, less than 1 hour prior to Jackson storm. Graphic courtesy of MeteoStar LEADS On-Line

Infra-Red Satellite Photo at 2:30 pm

Visible Satellite Photo at 3:00 pm

Pocatello Radar Image at 3:15 pm (Note the severe thunderstorm & tornado boxes just Southwest of Jackson)

Image from the MountainWeather Lightning Detector on Top of Snow King Mountain at around 3:30 pm

Image from lightning detector about the time hail was falling in town and thunderstorm was right overhead

Hailstone

Jim Woodmencey, meteorologist

Temperatures will be warming up pretty significantly around the Western US the rest of this week and into early next week (June 5 to 11) not just at the lower elevations but also up at higher elevations, were there is still significant snow to melt above about the 9,000-ft. elevation.

At around 10,000-ft. this week in the Tetons, for example, temps will get into then 60’s during the day and not re-freeze overnight, only dropping into the 40’s for overnight lows. This will lead to melting occurring 24-hours a day for several days in a row.

Settled Snowdepths on Wednesday June 5, 2013
Rendezvous Bowl (Elevation 9580-ft.) = 44 inches
Targhee  Snotel (Elevation 9260-ft.) = 61 inches

Snowpacks should be shrinking pretty significantly as we go into next week. And expect rising creeks and rivers from the runoff, the peak of that should be seen about the third day into the meltdown.

Snow Depth Map	Snow Water Map	River & Reservoir Levels

This is a big change from the last couple of weeks of relatively cool temps, below freezing at 10,000-ft. most nights and highs generally in the 40’s most days. And there were even a few days when we had snow accumulating above 9,000-ft. in the mountains.

Post by Jim Woodmencey, meteorologist
Graphics from NOAA & BOR

Jim Woodmencey, meteorologist

Powder skiing in late May? Well, that might seem like a bit of a stretch, but we are actually accumulating a little snow this week at the higher elevations in the Teton Mountains, above about 9500-ft. the last 24-hours. Snow levels will probably get down closer to 8,000-ft. as overnight temps get down into the 20’s at 10,000-ft. the next two nights. Total new snow at 10,000-ft. or higher in the Teton Range could be between 3 & 6 inches by Friday.

This is due to a complicated weather pattern that includes a couple of cold Low pressure systems extending across the Pacific Northwest and northern Rockies.

Powder this late in the year may not excite you, at all, especially if you were dreaming of maybe one last weekend of spring corn-skiing up high. And for those who would just love to see it all melt and get on with summer, there is some promise of that next week and the week after.

Summer Weather Ahead

We do flip a switch on Saturday June 1st, with at least more spring-like weather over the weekend, plenty of sunshine and temps warming up pretty quickly. High temps at 10,000-ft. get back up into the 50’s by Sunday afternoon. Which would turn powder to slush pretty quickly. In the valley, we should see temps returning closer to normal for this time of year, with highs in the upper 60’s to around 70.

Beyond that, we should stay close to or slightly warmer than normal for the first week of June. And it looks even more promising for warmer & drier weather in the western US as we go into the second week of June. (See maps below for expected conditions).

14-Day Outlook Maps for June 5 to 11, 2013
Temperatures	Precipitation

Isolated thunderstorms that developed Wednesday afternoon produced some fairly impressive wind gusts in some areas around the valley. These were downdrafts coming down from the base of the thunderstorms, which then spread out horizontally as they come in contact with the ground.
Strong downdraft winds are more common with dry-type thunderstorms, in other words, ones that don’t produce much rainfall.

These storm cells were tracking from the South to the North, tracking right over Snow King Mountain and the Town of Jackson. They formed along a weak cold front that was stalled out over western Wyoming, which gave them an extra boost (see map below).

Sample of Wind Gust Speeds at around 3:30 pm Wednesday May 22, 2013:
Town of Jackson = 41 mph
South Park= 39 mph
Snow King Mountain= 66 mph
Jackson Airport = 32 mph
Timbered Island, GTNP= 48 mph
Teton Pass= 31 mph
Raymer (JHMR-Headwall)= 97 mph

Wednesday Afternoon’s Weather Map (22MAY13)

Last Spring’s Wind Gusts

Wind gusts were not as strong in the valley as they were last Spring with some dry thunderstorms that we had here in Jackson Hole, Those also moved along a similar path, from South to North, passing directly over Snow King Mountain, on June 4, 2012.
Gusts in town were clocked at 59 mph and 51 mph at the airport.
(See blog post from June 18, 2012)

Post by Jim Woodmencey, meteorologist
Map Graphic from MeteoStar

Happy Mother’s Day! And a nice day it should be, with what may be our first “official” day this year with a high temperature over 70 degrees.
At the Jackson Climate Station the high temp the last two days almost made it to 70, with a high Saturday of 67 and the high Friday of 68.
Other thermometers around the area did reach 70 or better, at the Teton County offices that instrument was 70 both Friday & Saturday. The automated station at the USFS office hit 71 Friday and 72 Saturday.
Everyone’s thermometer should get over 70 today.
The reason we are getting warmer is due to a large and warm Ridge of High pressure that is sitting over the Western US. There is some very warm air over California that is pushing north under that Ridge today. For example, it was in the 90’s in Central California yesterday, and 109 degrees in Death Valley, the hottest place in the Country.
That’s quite a change from the weather we had at the beginning of the month in Jackson, with a high around 40 and 5 inches-plus of snow in the valley on May 1st.
If Mom needs it cooler, she could go to Northern Michigan, where it will be cold enough to snow on Mother’s Day. Or, to Pt. Barrow, Alaska where highs will be in the 30’s.
Back to work for me on Monday morning with the Jackson Hole Forecast.
But thought I’d better get updated on what the weather pattern is and prep myself before diving back in tomorrow.
Happy Mother’s Day!

Posted by Meteorologist Jim Woodmencey
Graphics from NWS

Maps below shows weather pattern @ 10,000-ft.
And Surface Map for Sunday

Surface Map for Mother’s Day

Last week I had the opportunity to work with a group of US Air Force Special Operations guys from the 10th Combat Weather Squadron on an avalanche course here in Jackson. This course was run in conjunction with the American Avalanche Institute. Guide and instructor Christian Santelices (a local Exum Mountain Guide) and Sarah Carpenter (co-owner of AAI) also assisted, as we spent six days working on basic and advanced avalanche topics and skills.

This is the third spring in a row that I have worked with this group, always different guys, but always top-notch. Their ability to absorb and then apply new subject matter constantly amazes me. What I like most about these guys is they are all Air Force trained weather forecasters, some even have degrees in meteorology, as well. And, they are tough as nails when they are out in the mountains. Especially considering they came here from sea level!

We worked on both Teton & Togwotee Passes and had good “winter-like” conditions, for mid April.

This next week I will be going to their headquarters and teaching a Mountain Weather Forecasting Course to this same group. The goal is to provide them with the knowledge and skills necessary to be able to forecast both weather & avalanches in the mountainous regions they are often called to work in.

“Combat-Weather”, I’m glad no one is shooting at me while I’m forecasting! That’s a different level of pressure to be accurate!

Post & Photo by meteorologist Jim Woodmencey

Some of the 10CWS Team on top of Breccia Peak

On this first full day of the Spring Season I would like to give you a preview of a new page dedicated to Wyoming’s Weather. I am in the process of making some changes to the mountainweather.com website, and will be doing some re-arranging of the Navigation. A little “spring cleaning”, if you will. As well as adding some other new pages in the coming weeks.

Spring officially began today, Wednesday March 20, 2013 at 5:02 a.m. MDT.  According to the calendar it’s Spring, but our weather the next few days will be more like mid-winter!

Forecast Map for Wednesday, March 20.

Don’t like to read? You can now listen to MountainWeather’s Jackson Hole Forecast, anywhere, anytime. New audio version of the forecast is now available ………look for the audio button on the Jackson Hole Forecast page on both the main MountainWeather.com site and the mobile version of the website.

Find this button at top right corner of the forecast on the main website	Find this button at top of the forecast on the mobile site