Saturday, June 29, 2013

Time-Lapse of Cumulonimbus over Caribou Mountains 6/29/2013

The web cam located at Star Valley Ranch captured some impressive and rapid development of cumulonimbus over the mountains to the west of Star Valley.  The storm formed and then dissipated just as fast.

Time Lapse of Cumulonimbus

Friday, June 28, 2013

Wednesday, June 26, 2013

Potentially Deadly Heat Wave Arizona, Nevada and California Deserts This Weekend

For those who live, or are in Star Valley currently, we can be thankful.  It is going to be a very hot several days in the desert valleys of the Southwest.  The culprit is an unusually large upper high pressure system that will develop by the end of this week. Following are two 500mb charts that  provide the explanation of the impending heat wave. The first is this Wednesday morning, June 26th and then for mid day Saturday June29th.

This large upper high will provide ideal conditions for maximum heating, clear skies, warm very and dry subsiding air along with near maximum daylight hours.

Here are forecasts for major desert metropolitan areas through the coming weekend.

The Phoenix WFO has a Video web briefing  that summarizes the upcoming heat wave and precautions that should be taken.

Web Briefing on Upcoming Heat Wave

This heat wave is coming up on the 100th Anniversary of the All-Time hottest temperature ever recorded on the Earth in Death Valley of 134 degrees.  The official Death Valley weather station at Furnace Creek is forecast to reach within several degrees of that record by this weekend.

For real weather junkies there is a ceremony that will be held at Furnace Creek on the Anniversary of the record.  Following is the information for those who would like to attend!

Friday, June 21, 2013

Weekly Weather Briefing from Riverton WFO

The following is the link to the Weekly weather briefing issued by the Riverton WFO

Riverton WFO weekly weather briefing

Star Valley Summer Will Start Next Week

While today, the 21st of June is officially the start of summer(summer solstice),  Star Valley recently has been experiencing more Spring like temperatures.

Following is the graph from the Thayne ES weather station for the past 30 days.

Thayne ES max/min temperatures May 20-June 20 2013
Daytime temperatures have been relatively mild, but nights have been cool, many below freezing.

Following is the Weather Table for the Month of June at Thayne ES thus far
Noticeably is the the lack of any appreciable precipitation so far this June.
The current cool weather is the result of an upper trough of low pressure over the Northwest U.S.
500 MB Analysis midnight Thursday June 20 2013
This pattern will change over this next week leading to a large high pressure over the Western States.

500 MB forecast midnight Tuesday June 25 2013

500 MB forecast midnight Friday June 28 2013

Reflecting this forecast the 6-10 temperature forecast for the end of next week through the weekend calls for very warm
conditions in the mountain west

For the same time period the CPC is indicating that precipitation could be returning to the region.

This could reflect the beginning of the Southwestern Monsoon. So there is some hope of June ending on a wetter note, even with temperatures likely reaching into the upper 80s and low 90s by the end of next week.

Tuesday, June 18, 2013

Supercell Thunderstorm Visits the Tetons

Supercell Thunderstorm visits the Tetons.

Late afternoon on June 12, 2013 a Supercell Thunderstorm developed over the upper Snake River Valley of Eastern Idaho and rapidly moved east across the Tetons and the Jackson Hole region.  Though no tornados were reported(and likely did not develop) this storm was a classic Supercell as seen both through the photographs taken and the radar signatures.  Jim Woodmencey(Woody) of has provided a couple excellent blogs on his web site with the photographs and other interesting meteorological observations associated with the Supercell.  The photo of the day was taken from Snow King looking west at the approaching storm

Here is a link to Woody's blog concerning the storm.  Be sure to check out the blogs on both June 12th and 17th.

MountainWeather Blog

Thanks Woody

Friday, June 14, 2013

Freezing Temperatures Saturday Morning

A strong cold front moved across Star Valley Thursday evening, and in its wake a much cooler air mass now covers Western Wyoming.  High pressure now  building into the area assures several near perfect weather days ahead.

However, conditions tonight and Saturday morning will be ideal for strong radiational cooling, leading to frost most areas Saturday morning.  Temperatures in the typical colder valley locations primarily near the Salt River will likely drop below freezing by midnight, Friday night and possibly bottoming out in the mid to upper 20s by daybreak Saturday.

Obviously this is a threat to frost sensitive vegetables that may have just been planted such as tomatoes etc. These plants should be covered tonight.

Warming is then expected through the Fathers Day weekend, with a lessening frost threat Sunday morning.

Thursday, June 13, 2013

Fathers Day Weekend Weather Expected to be Ideal in Wyoming

The weekly issuance of the Weather Briefing from the Riverton Forecast Office highlights the near perfect weekend weather coming up in much of Wyoming.

Weekly Video Weather Briefing

Monday, June 10, 2013

Final 2013 Wyoming Water Supply Outlook

Hopefully we do not have a repeat of the summer of 2012, when it was so dry.  Water supply will be adequate provided favorable summer shower activity occurs.

Final 2013 Wyoming Water Supply Outlook---June 7th

...May basin precipitation was near 96 percent of average across Wyoming…
…Mountain snowpack across Wyoming was 65 to 70 percent of average by early June… 
Below normal streamflow volumes are expected for the rest of the summer across most of Wyoming’s major watersheds…
…Total reservoir capacity in Wyoming was near 70 percent by early June…
May basin precipitation across Wyoming was near 96 percent of average. Precipitation numbers varied between 187 percent of normal over the Belle Fourche River Basin to 60 percent of normal over the Upper North Platte Drainage.
Mountain snowpack across Wyoming decreased to below normal at around 65to 70 percent of average by early June.  Snow water equivalents (SWEs) were45 to 55 percent of average across western and central Wyoming watersheds; while SWEs in southeast Wyoming drainages were near 70 percent of normal.
Streamflow snowmelt volumes are expected to be below normal for the rest of the summer across almost all of Wyoming’s major basins.  
Total reservoir capacity in Wyoming was near 70 percent by early June.   Levels at the major reservoirs in early June varied from 39 percent capacity at Pathfinder Dam to 95 percent capacity at Jackson Dam

Thursday, June 6, 2013

Three Years Later (June 6 2010)

On June 6, 2010 a vicious storm crossed parts of Star Valley during the evening, producing hail and very strong winds.  While trees were reported down and large hail occurred from around Star Valley Ranch south to near  Grover, the greatest damage was up Willow Creek Canyon.  Very large pines were uprooted at some distance above the mouth of the Canyon, indicating the likelihood of an intense downburst.

A map below indicates ground zero for the downburst.

Following are several photos taken on June 6th 2013, 3 years later, of the obvious evidence of the power of the winds near the A Marker.

Google Maps Image 2009- pre-blowdown
Post-blowdown from BING maps
Additional Post-Blowdown from BING maps

Also a photo was taken looking north from Star Valley Ranch as the storm was moving by, which was not toward the most intense portion .

On examination of the Pocatello radar data of the storm it was undoubtedly a Supercell.  While tornados are associated with Supercells, in this case there is no evidence of any tornadic circulation. The storm was moving at close to 60mph and as the following radar images of the storm will attest, it was very impressive.

The first image shows a vertical radar cross-section with a very strong and high reflectivity core to above 30,000 feet and overall storm top to above 50,000 feet as it was approaching the Wyoming/Idaho  line.

Pocatello Doppler Radar  7:19 PM June 6 2010

 A linear mode typical of a damaging wind squall line is shown approaching Star Valley in a horizontal display

Pocatello Doppler Radar  7:19 PM June 6 2010

The center portion of the line indicated potential for large hail heading for about the Narrows.

The following is the Vertically Integrated Liquid(VIL) which displays the area of greatest  large hail potential.

Pocatello Doppler Radar VIL 7:19 PM June 6, 2010

Pocatello Doppler Storm Relative Velocity 7:06 PM June 6, 2010
The above image is of the horizontal velocity toward/away from the radar.  It is a storm relative image and appears to be a broad counter-clockwise rotation around the center of the most intense part of the line, indicating a Supercell.

While a tornado could not be ruled out with a storm of this intensity, the character of the storm and wind fall of the trees, all up-canyon, a downburst with speeds possibly to 80 mph or more was the likely culprit of the observed damage.

Sunday, June 2, 2013

Three Feet of Snow!

The recently departed storm that provided the second period of beneficial rainfall for Star Valley in the month of May, as expected put down a little snow in the higher mountains.  It appears that the snow level remained generally above about 8000 feet.  Willow Creek Snotel had several inches of wet snow.  However it was a different story in the Big Horn Mountains.  

Star Valley Ranch recorded 3.32 inches of rain for the month of May, while the station 5 miles southsoutheast of Smoot had 2.70 inches.

Riverton Forecast Office put together a summary of the Snow storm in the Big Horns.

3 Feet of Snow at the End of May?

The National Weather Service
Building a Weather-Ready Nation

An excruciatingly slow moving upper level low pressure system tracked across northern Wyoming and into the northern plains over the past five days. It was also accompanied by an abundance of moisture and some very cold temperatures aloft. This system will continue to wrap moisture around the low and into the region through Saturday.

 Click Image to Enlarge
The above image shows the track of the storm system (yellow arrow) over the past few days. The current position of the upper level low center is located over the Dakotas as of Friday morning, however it will continue to wrap around moisture and bring precipitation (spotty image) in the cold air (blue shades) to the Bighorns through Saturday. Snow and rain will finally taper off on Saturday afternoon and evening.
 Click Image to Enlarge
The above image shows the amount of liquid precipitation that fell over central and northern Wyoming over the past 7 days. (Data is missing for Southwest Wyoming)

Several inches to several FEET of snow fell across the northern mountains of Wyoming, while mainly rain fell below 8500 feet. So far, the big winner in the snow department is the Wyoming High Country Lodge, where three feet of snow has fallen in the past couple of days!

Click on Image to Enlarge
Our fantastic weather spotter at the Wyoming High Country Lodge sent us these photos. The picture on the left was taken just a few days ago, while the picture on the right was taken at about 10:00am on Friday morning! There have been reports of damage caused by several trees that collapsed under the weight of the new snow. What a difference a couple of days make!

More Photos of the WY High Country Lodge on May 31st
Click Image to Enlarge
Snowmobiling at the end of May, anyone?
A big "thank you!" to the Wyoming High Country Lodge for sending these photos to us and for letting us use them.
Click Image to Enlarge
One of the many fallen trees around the lodge.
A big "thank you!" to the Wyoming High Country Lodge for sending these photos to us and for letting us use them.

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Reported Snowfall Totals 
CountyStation NameSnowfall
Big HornWyoming High Country Lodge36
 Bald Mountain Snotel24
 Shell Creek Snotel8
 Bone Springs Divide Snotel4
CountyStation NameSnowfall
WashakiePowder River Pass Snotel8
CountyStation NameSnowfall
JohnsonCloud Peak Reservoir Snotel4
 Bear Trap Meadow Snotel4
 Little Goose Snotel1