Star Valley Weather

Powerful Polar Jet Stream Blasts Western Wyoming

2012-02-22T20:15:00.000-08:00

Star Valley has avoided the impact of the Polar Jet and it's associated storm track much of the winter. Such was not the case the past couple of days as was well forecast by the computer models. An intense band of jet stream winds raced southeastward across our area Wednesday. The 300 mb analysis (around 30,000 feet MSL) from Wednesday evening shows the core of the 140-160 kt jet aimed right for western Wyoming

Around mountain top level at 700mb Wednesday evening winds were running from 60-70 kt.

Combined with warm air that spread eastward, conditions were favorable for strong mixing of the jet stream winds to the ground level at most locations. The higher elevations, particularly mountain ridges and passes were most affected. Few observations are available at these remote locations with a couple notable exceptions. The automated site atop Mt. Coffin on the southern end of the Wyoming Range at almost 11,000 feet hit a peak gust of 140 mph at 8:30 pm. The observations at the top of the Ski Lift above Teton Village at 10,300 feet had a peak gust of 76 mph around 4pm and 77 mph at 9:45 pm..

Exceptionally strong winds affected much of Star Valley Wednesday afternoon and evening. Some of the notable gusts and time of occurrence were:

Alpine                      G62 mph   12:32 pm
Star Valley Ranch      G56 mph    7:17 pm
Osmond Elementary   G54 mph    7:45 pm
Thayne Elementary    G50 mph    7:29 pm
Etna Elementary         G47 mph 6: 44 pm
Smoot    G43 mph   7:40 pm

Preceding the strong winds and warmer air, snow fell across all of Star Valley much of Tuesday before changing to rain Tuesday night. Snow reports ranged upwards from just a few inches in the Afton and Smoot area to an observed 15 inches just to the southeast of Thayne. Star Valley Ranch measured an even foot bringing the current snow depth to 40 inches. A reliable observer just northeast of Etna had almost 8 inches before the rain made it a sloopy mess.

Colder air will arrive later tonight dropping temperatures well below freezing by morning where they will remain through the coming weekend.. This will lead to very icy conditions Thursday morning in areas where the melting that occurred on Wednesday, refreezes.

Weekend Snow Gone, But More on The Way

2012-02-19T21:08:00.000-08:00

The weekend storm has moved on with generally 2 inches of new snow in most Star Valley locations. The observer south of Smoot only had an inch with Star Valley Ranch somewhat an outlier with 6 inches observed by early Sunday afternoon. The snow pack still remains a little below normal, and certainly far behind last year in the adjacent mountains.

The Willow Creek Snotel has shown a strong recovery from the very slow start on the Winter snow pack.

Now looking ahead a major shift is underway with the storm track and more importantly the core of the wintertime polar jet taking direct aim at Star Valley this coming week.

Beginning this Sunday evening the weekend trough is moving on east as the strong polar jet is crossing the high pressure ridge in the Gulf of Alaska.


300 mb Analysis Sunday evening 2/19/12

By mid week the 130kt polar jet will be driving eastward just to the north of Star Valley.


300 mb forecast Wednesday evening 2/22/12

And by the end of the week while a deep trough develops over the central states, models are indicating strong low pressure troughing will be approaching the region.


300 mb forecast Friday evening 2/24/12

Although a 7-day model forecast is always of questionable accuracy, the idea of a major upper system crossing the western states appears to be a concern for next weekend


300mb forecast Sunday evening 2/26/12

Confidence is high that it will be a very snowy week, beginning Tuesday. The model forecast total precipitation for the next 7 days indicate a large area of greater than an inch of water content over much of the western Wyoming mountains including the Star Valley.

Total Precipitation for period from Feb 19-26 2012

Given the likely extended duration with the very strong, westerly upslope flow, new snow fall totals of 2-4 feet are certainly possible over the Tetons, Salt and Wyoming Ranges.

How much will accumulate on the floor of Star Valley is more of a question as the air mass moving into the area by Wednesday will warm considerably leading to very wet snow, possibly changing to rain for a time. However amounts of a foot or more certainly are a good possibility at least at higher valley locations, such as the south end and places such as Star Valley Ranch where elevations are near 6500 feet.

By Thursday colder air will move back across the area turning all the precipitation back to snow.

By next Sunday there is a good possibility that the mountain snow pack will be increased to above average levels, which would be quite the recovery from where they were in early January.

More Serious Snow On The Horizon

2012-02-17T11:48:00.000-08:00

While there has been at least a trace of snow observed at Star Valley Ranch for the past 10 days it has resulted in just 12 inches. Almost half(5 inches) fell last Sunday morning. There are signs that the storm track, which has been bypassing Star Valley much of February, will be more of a player in our weather for the remainder of the month.

A weak upper trough passing through the area will result in a couple inches of new snow today(Friday). This should be a rather low moisture content snow with snow to liquid ratios around 20:1. That is, if 20 inches of snow fell and that snow was melted, it would produce 1 inch of liquid precipitation. A wet snow would have ratios of 10:1 or less.

Examining the morning upper air analysis shows the weak system resulting in today's snow at 700mb(10,000 ft) tracking across the northern Rockies:

700 mb Analysis Friday Morning Feb 17 2012

While today's snow is rather obscure on the water vapor imagery this morning, a much more powerful storm is approaching the Pacific Northwest coast.


Water Vapor Imagery Friday AM February 17, 2012

There are still signs that the storm moving onto the Northwest coast later today will weaken as the energy again tries to split. Unlike recent systems, Star Valley and western Wyoming and southeastern Idaho should receive a period of significant snow as the upper trough passes this weekend.

With the current weak system passing on to the east the associated snow is expected to generally end by this evening.

Looking ahead by late Saturday afternoon, snow will return to the area as the storm now moving toward the Pacific Northwest, although having weakened, will be crossing the Idaho/Western Montana /Western Wyoming region.


700 mb Forecast Saturday evening Feb 18 2012

Below is an experimental forecast for the model snowfall over about the next 3 days. Basically, displayed are various model solutions for the same forecast period. By varying initial conditions of several different models, a total of about 16 different solutions of total snowfall are made for the Star Valley area. While the range of forecast snow is from just a couple inches to nearly a foot, the mean of all models is for around 6 inches. Probably of greatest importance is that all the solutions agree that the bulk of the snow will fall beginning late Saturday through Sunday evening.

For additional technical information as well as access to other model forecast fields and locations check out this link:

http://www.spc.noaa.gov/exper/sref/eplumes/index.php?PRM=Total-SNO&INC=ALL&NNC=&RT=09&max=&min=&SID=SVR

Greg Carbin the Warning Coordination Meteorologist at the Storm Prediction Center has developed the SREF Display and is looking for feedback.


SREF Forecast Total Snowfall from Friday morning until Monday evening Feb 17-20 2012 for Star Valley

Forecast snowfall amounts depend on several factors including snow to liquid ratios, accuracy of model solutions and location relative to terrain influences. Here in Star Valley all these play important roles. Thus, a forecast of how much snow is going to fall is one of the more difficult weather parameters to make.

Given these caveats it does appear that over the weekend, several inches of new snow are likely with the possibility of the most favored valley locations receiving from 4-6 inches along the west slopes of the Salt Range such as Smoot, Turnerville, Bedford and Star Valley Ranch. It does appear that higher elevations in the Tetons and Salt/Wyoming Ranges could get over a foot.

Active Cloud Day over Star Valley Captured on the Star Valley Ranch Cam

2012-02-15T18:33:00.000-08:00

The atmosphere over Star Valley on February 15, 2012, was moist and seasonably cold. The mid-February sun resulted in an interesting cloud day. Stable strato-cumulus clouds covered the valley during the morning. By early afternoon heating resulted in the clouds over the valley dissipating while even stronger heating of the higher terrain of the Caribou Range on the west side of the valley developed rather vigorous convective updrafts. Cumulus clouds quickly glaciated given the cold air aloft and snow showers then pelted the mountains. Since the steering winds were quite light these cumulus clouds remained over the Caribou Range during their relatively short life cycle. Upon cessation of daytime heating, the clouds quickly became strato-cumulus and once again spread back across the valley.

All of this rather active cloud day was captured by the web cam located in Star Valley Ranch. The animation speed of the video is 12 frames per second, with a minute between frames.

http://youtu.be/TsiXP3v1-Es

Snow So Far This Season in Star Valley vs the Winter of 2010-2011

2012-02-11T10:40:00.000-08:00

There are two active CoCoRaHS observers in Star Valley. One is located south of Smoot and the other one is at my home in Star Valley Ranch. The official snow season begins on Oct 1 each year. As of today, February 11th the total at the Star Valley Ranch site is 110 inches with 106 inches measured at the Smoot location. At the bottom of this blog will be the listing by day of the snowfall, precipitation and snow depth for each of the two locations.

The Smoot CoCoRaHS observer had measured 155 inches last year up until Feb 10th 2011. While this is about 4 feet more than reported thus far this year, another 132 inches fell after Feb. 10 2011 for a season total of 287 inches, or almost 24 feet!

An observer located near Thayne measured 210 inches for the 2010-2011 snow season or nearly 18 feet. So far this year he reports 93 inches. Another reliable observer located just northeast of Etna reports they have measured 66 inches since Oct.7 2011.

While we are far below last years snowfall, as can be seen from the Smoot observer, another 11 feet was measured after Feb. 10, 2011. While the large scale jet stream pattern continues to keep the storm track away from Star Valley, there is still much of the snow season still ahead.

For the past two winters there has been a web cam recording the snow depths at Star Valley Ranch. The current cam view of the snow stake can be seen at http://www.camviewing.com/mosaic/.

There are two videos available to compare last winter with the current one. The first link was taken using the camera that has since been moved to the Star Valley Ranch Public Works building and provides a view across the valley. The cam being used to monitor the snow stake this year is of somewhat less quality.

One photo a day grabbed around noon is used to put together a movie of the history of each year.

The snow season 2010-2011 can be found here:

http://www.youtube.com/watch?v=pvym_ENf6L8

For the winter of 2011-2012 the loop begins on December 14th and so far covers every day up to February 10th:

http://www.youtube.com/watch?v=gbqPGHeX98w

Following are the daily reports from the two CoCoRaHS sites so far this snow season:

WY-LN-2
Smoot 4.9 SSE
Lat: 42.5519166
Lon: -110.8884333

WY-LN-17
Thayne 4.7 NNE
Lat: 42.976495
Lon: -110.949658

* indicates Multi-Day Accumulation Report

Station

WY-LN-2

WY-LN-17

Date	Precip	Snowfall	Core Precip	Total Snow Depth	Total SWE	Precip	Snowfall	Core Precip	Total Snow Depth	Total SWE
10/01/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/02/2011	0.00	0.0	NA	NA	NA	T	NA	NA	NA	NA
10/03/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/04/2011	0.02	NA	NA	NA	NA	0.00	0.0	NA	NA	NA
10/05/2011	0.38	NA	NA	NA	NA	0.08	NA	NA	NA	NA
10/06/2011	0.48	1.0	NA	1.0	NA	0.27	0.5	NA	0.5	NA
10/07/2011	1.08	14.0	NA	15.0	NA	0.90	10.0	NA	8.0	NA
10/08/2011	0.24	2.0	NA	14.0	NA	0.26	1.0	NA	4.0	NA
10/09/2011	0.00	0.0	NA	5.0	NA	0.03	NA	NA	1.0	NA
10/10/2011	0.00	0.0	NA	3.0	NA	0.00	0.0	NA	T	NA
10/11/2011	0.14	NA	NA	1.0	NA	0.09	NA	NA	NA	NA
10/12/2011	0.19	NA	NA	NA	NA	0.32	NA	NA	NA	NA
10/13/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/14/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/15/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/16/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/17/2011	0.42	NA	NA	NA	NA	0.64	NA	NA	NA	NA
10/18/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/19/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/20/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/21/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/22/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/23/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/24/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/25/2011	0.08	NA	NA	NA	NA	0.00	0.0	NA	NA	NA
10/26/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/27/2011	0.00	0.0		NA	NA	0.00	0.0	NA	NA	NA
10/28/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/29/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/30/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
10/31/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
11/01/2011	0.10	NA	NA	NA	NA	0.00	0.0	NA	NA	NA
11/02/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
11/03/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
11/04/2011	0.00	0.0	NA	NA	NA	0.00	0.0	NA	NA	NA
11/05/2011	0.19	2.0	NA	2.0	NA	0.32	4.0	0.32	4.0	NA
11/06/2011	0.07	2.0	NA	3.0	NA	0.07	2.0	NA	5.0	NA
11/07/2011	0.00	0.0	NA	3.0	NA	T	T	NA	3.0	NA
11/08/2011	0.00	0.0	NA	3.0	NA	T	0.2	NA	3.0	NA
11/09/2011	0.00	0.0	NA	2.0	NA	T	T	NA	2.5	NA
11/10/2011	0.00	0.0	NA	2.0	NA	0.00	0.0	NA	2.5	NA
11/11/2011	0.00	0.0	NA	2.0	NA	0.00	0.0	NA	2.0	NA
11/12/2011	0.14	3.0	NA	4.0	NA	0.04	2.0	NA	4.0	NA
11/13/2011	0.56	12.0	NA	14.0	NA	0.53	14.5	NA	13.0	NA
11/14/2011	0.15	2.0	NA	15.0	NA	0.20	3.5	NA	12.0	NA
11/15/2011	0.00	0.0	NA	12.0	NA	0.00	0.0	NA	9.0	NA
11/16/2011	0.00	0.0	NA	11.0	NA	T	0.0	NA	8.0	NA
11/17/2011	0.00	0.0	NA	10.0	NA	0.00	0.0	NA	8.0	NA
11/18/2011	0.06	2.0	NA	11.0	NA	0.34	5.0	NA	10.0	NA
11/19/2011	0.39	8.0	NA	15.0	NA	0.15	3.0	NA	11.0	NA
11/20/2011	0.00	0.0	NA	14.0	NA	T	T	NA	10.0	NA
11/21/2011	0.15	3.0	NA	15.0	NA	0.19	4.5	NA	14.0	NA
11/22/2011	0.00	0.0	NA	14.0	NA	T	T	NA	11.0	NA
11/23/2011	0.00	0.0	NA	13.0	NA	T	T	NA	10.0	NA
11/24/2011	0.00	0.0	NA	13.0	NA	0.00	0.0	NA	8.0	NA
11/25/2011	0.11	2.0	NA	15.0	NA	0.02	0.5	NA	8.0	NA
11/26/2011	0.00	0.0	NA	14.0	NA	0.03	1.0	NA	8.0	NA
11/27/2011	0.00	0.0	NA	13.0	NA	0.00	0.0	NA	7.0	NA
11/28/2011	0.00	0.0	NA	13.0	NA	0.00	0.0	NA	7.0	NA
11/29/2011	0.00	0.0	NA	12.0	NA	T	T	NA	6.0	NA
11/30/2011	0.00	0.0	NA	12.0	NA	0.00	0.0	NA	6.0	NA
12/01/2011	0.09	2.0	NA	14.0	NA	0.09	2.0	NA	8.0	NA
12/02/2011	0.00	0.0	NA	14.0	NA	0.00	0.0	NA	7.0	NA
12/03/2011	0.00	0.0	NA	13.0	NA	0.10	2.0	NA	9.0	NA
12/04/2011	0.12	2.0	NA	15.0	NA	0.01	0.2	NA	8.0	NA
12/05/2011	0.07	1.0	NA	16.0	NA	T	T	NA	8.0	NA
12/06/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/07/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/08/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/09/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/10/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/11/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/12/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/13/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	8.0	NA
12/14/2011	0.09	2.0	NA	17.0	NA	0.08	2.0	NA	10.0	NA
12/15/2011	0.06	1.0	NA	17.0	NA	0.03	1.0	NA	11.0	NA
12/16/2011	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	9.0	NA
12/17/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	9.0	NA
12/18/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	9.0	NA
12/19/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	9.0	NA
12/20/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	9.0	NA
12/21/2011	0.00	0.0	NA	16.0	NA	0.00	0.0	NA	12.0	NA
12/22/2011	0.19	3.0	NA	19.0	NA	0.19	3.0	NA	12.0	NA
12/23/2011	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	12.0	NA
12/24/2011	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	12.0	NA
12/25/2011	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	12.0	NA
12/26/2011	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	12.0	NA
12/27/2011	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	10.0	NA
12/28/2011	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	10.0	NA
12/29/2011	0.33	3.0	NA	20.0	NA	0.80	1.0	NA	10.0	NA
12/30/2011	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	10.0	NA
12/31/2011	0.13	2.0	NA	20.0	NA	0.42	5.0	NA	15.0	NA
01/01/2012	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	14.0	NA
01/02/2012	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	13.0	NA
01/03/2012	0.00	0.0	NA	18.0	NA	0.00	0.0	NA	13.0	NA
01/04/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	12.0	NA
01/05/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	12.0	NA
01/06/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	11.0	NA
01/07/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	0.00	11.0	3.90
01/08/2012	0.00	0.0	NA	17.0	NA	T	T	NA	11.0	NA
01/09/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	11.0	NA
01/10/2012	0.00	0.0	NA	17.0	NA	0.00	0.0	NA	11.0	NA
01/11/2012	0.14	2.0	NA	19.0	NA	0.14	2.0	NA	13.0	NA
01/12/2012	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	13.0	NA
01/13/2012	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	13.0	NA
01/14/2012	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	12.0	NA
01/15/2012	0.00	0.0	NA	19.0	NA	0.00	0.0	NA	12.0	NA
01/16/2012	0.08	1.0	NA	20.0	NA	0.08	1.0	NA	13.0	NA
01/17/2012	0.00	0.0	NA	20.0	NA	0.00	0.0	NA	13.0	NA
01/18/2012	0.00	0.0	NA	20.0	NA	0.00	0.0	NA	13.0	NA
01/19/2012	0.72	9.0	NA	27.0	NA	0.70	10.0	NA	21.0	NA
01/20/2012	0.59	5.0	NA	30.0	NA	0.60	5.0	NA	23.0	NA
01/21/2012	0.57	5.0	NA	35.0	NA	0.35	2.0	NA	25.0	NA
01/22/2012	0.63	4.0	NA	34.0	NA	0.49	4.0	NA	26.0	NA
01/23/2012	0.00	0.0	NA	34.0	NA	T	T	NA	26.0	NA
01/24/2012	0.20	3.0	NA	35.0	NA	0.20	4.0	NA	28.0	NA
01/25/2012	0.00	0.0	NA	34.0	NA	T	T	NA	27.0	NA
01/26/2012	0.00	0.0	NA	34.0	NA	0.04	0.5	NA	27.0	NA
01/27/2012	0.31	3.0	NA	36.0	NA	0.24	5.0	NA	30.0	NA
01/28/2012	0.00	0.0	NA	34.0	NA	0.00	0.0	NA	28.0	NA
01/29/2012	0.00	0.0	NA	34.0	NA	0.00	0.0	NA	27.0	NA
01/30/2012	0.00	0.0	NA	34.0	NA	0.00	0.0	NA	25.0	NA
01/31/2012	T	T	NA	34.0	NA	0.04	1.0	NA	25.0	NA
02/01/2012	0.00	0.0	NA	34.0	NA	0.00	0.0	NA	25.0	NA
02/02/2012	0.16	2.0	NA	35.0	NA	0.15	3.0	NA	27.0	NA
02/03/2012	0.00	0.0	NA	34.0	NA	0.00	0.0	NA	26.0	NA
02/04/2012	0.00	0.0	NA	33.0	NA	0.00	0.0	NA	25.0	NA
02/05/2012	0.00	0.0	NA	33.0	NA	0.00	0.0	NA	25.0	NA
02/06/2012	0.00	0.0	NA	33.0	NA	0.00	0.0	NA	25.0	NA
02/07/2012	0.00	0.0	NA	33.0	NA	0.00	0.0	NA	25.0	NA
02/08/2012	0.00	0.0	NA	33.0	NA	0.02	0.5	NA	25.0	NA
02/09/2012	0.17	2.0	NA	34.0	NA	0.06	2.0	NA	26.0	NA
02/10/2012	0.00	0.0	NA	33.0	NA	T	T	NA	25.0	NA
02/11/2012	0.14	1.0	NA	34.0	NA	0.09	2.0	NA	25.0	NA

Pattern Change Again, Still No Big Snows in Sight for Star Valley

2012-02-09T10:42:00.000-08:00

Weak disturbances tracking southeastward across Star Valley have produced periods of light snow the past couple of days. Reported snow totals throughout the valley have generally been from 1 to no more than 2 inches. Snow depth range from a reported 2 feet at the Alpine and Star Valley Ranch locations to close to 3 feet south of Smoot.

A photo taken this morning in Star Valley Ranch is typical of many areas in the valley

In other parts of the country this sight could result in anxiety and travel concerns, for Star Valley residents it is just another winter day. However, in other regions of the World what we have to deal with in Star Valley, even during a snowy winter, is small potatoes. In particular the Japanese Alps on Honshu Island, one of the snowiest locations on earth, experience amazing snowfalls.

Here are a couple photos from this region.

A very interesting blog is available discussing the snowier parts of the globe:

http://www.wunderground.com/blog/weatherhistorian/article.html?entrynum=60

Looking ahead the current pattern with a high pressure ridge to the west of Star Valley


500 mb analysis Thursday Morning 2/9/12

is forecast to once again readjust toward a split flow pattern, directing storms systems both to the north and south.

By Tuesday of next week this split flow will be in place


500 mb forecast Tuesday 2/14/12

with the storm track across the Southwestern States and in western Canada.

While this does not favor a dry weather regime for Star Valley, any snow that falls will be generally light, similar to what has occurred recently. An interesting way to look at what the models are forecasting is through a meteogram over the next week or so. This one is for Jackson Wyo


Meteogram Jackson WY Feb 9-17 2012

Of particular interest over the next week, based on the model, is that it only can generate a total of 14 mm of precipitation which converted to inches is around a half inch. Most of that is toward the end of next week. Additionally no big temperature changes are likely until at least the end of next week as the cold air in Canada remains north of us.

Star Valley Winter Inversions

2012-02-07T10:20:00.000-08:00

Once again this week Star Valley(as has been the situation several times this winter) is being affected by a strong temperature inversion. Since instrumented balloons sample the vertical structure of the air mass at widely spaced locations(the closest sites to Star Valley are Riverton and Salt Lake City), the only real way to detect the inversions is by sampling the temperatures at varying elevations around the valley.

As an example of a vertical temperature profile that is similar to the one over Star Valley under these conditions, is the radiosonde released a couple mornings ago at Kelowna in southern British Columbia.

Kelowna, British Columbia 1200GMT 2/5/2012

In this case the temperatures were warmer at 700 mb(10,000 feet) than near the ground.

Following are the meteograms of temperatures for the last 5 days(Feb 3-7) of observations from several weather stations in and near Star Valley.

The Afton station has been most affected by the persistent inversion


Afton Temperatures Feb 3-7 2012

It is apparent that the inversion became established the night of February 4th and for the following three mornings minimums dipped to well below zero. During the afternoon, even under sunny conditions, temperatures could only climb into the mid teens.

A similar scenario is observed by the station at Thayne Elementary School.


Thayne ES Temperatures Feb 3-7 2012

Once the inversion was established on the morning of the 4th, minimums have been well below zero with afternoon highs briefly reaching to about 20 above.

At the Star Valley Ranch station which is about 300 feet above the valley floor as well as adjacent to the west slopes of the Salt Range, temperatures typically are not as cold under strong inversion conditions.

Star Valley Ranch Temperatures Feb 3-7 2012

Not only are nighttime minimums not as cold as the valley floor(lowest observed was 3 above)but the sun is more effective in warming the afternoons with maximums running 15-20 degrees higher than at the Afton Station!

The Box Y station, which is located in the Greys River Canyon, is interesting as well. While strong nighttime inversions develop due to the sheltering affects of the Wyoming/Salt Ranges, the canyon is considerably narrower than Star Valley, which allows the daytime heating to more effectively remove the inversions.

Box-Y Temperatures Feb 3-7 2012

While it gets as cold as the coldest Salt River Valley locations at the Box Y Station, afternoon temperatures have been near or above freezing, similar to Star Valley Ranch.

During the morning hours there have been areas of fog trapped under the inversion. An example of this is the photo taken Sunday morning near Grover where the temperature at the time was minus 8F.


Sunday morning February 5 2012

In this photo is visible the thin layer of fog. Also visible is the accumulated Hoar Frost that has been deposited on the trees by the fog. The fog has been much thicker during the mornings at times near the Salt River.

By the end of February the sun will be providing sufficient insolation that nighttime inversions will weaken considerably during the afternoon.

Ho-Hum

2012-02-02T16:42:00.000-08:00

Ho-Hum describes the weather pattern expected in Star Valley well into the month of February. It was fortunate that the nearby mountains received a couple big storms recently as there is little chance of addition to the snow pack for some time. As of Feb 2 the SNOTEL site at Willow Creek indicated almost normal snow pack had been reached.

Looking ahead at the large scale flow pattern places Star Valley far removed from the storm track for the foreseeable future.


500 mb forecast Sunday 2/5/12

500 mb forecast Wednesday 2/8/12


500 mb forecast Saturday 2/11/12

This quiet weather period should be dominated by sunny days and cold nights. Inversions will dominate the valleys, including Star Valley, with the warmer temperatures in the higher elevations both day and night. With the steadily increasing amount of daytime heating with longer daylight, coldest valley locations should not fall much below zero. Afternoon highs could climb above freezing most days.

New Month to Begin Very Quiet After Early Week Snow

2012-01-29T20:40:00.000-08:00

Once again as has happened a couple times already this winter, it appears that Star Valley will experience a prolonged period of snow free days in early February. For the beginning of the coming work week, a series of relatively weak disturbances will bring periods of mostly light snow to the area. The Water Vapor imagery Sunday evening shows the first system now moving onshore in the Pacific Northwest followed closely by a 2nd and even 3rd system.

GOES Water Vapor Imagery Sunday evening 1/29/12

The first system should spread snow across much of Star Valley beginning by early Monday afternoon. Amounts should be greatest in the surrounding mountains with a couple inches possible in the Valley by evening.

The next weaker disturbance will likely continue a threat of at least some light snow going into Tuesday with a possible overnight break between systems.

The major change in the pattern will begin by mid week as an upper ridge of high pressure builds strongly into the Western States and then dominates our region at least through the coming weekend. As seen in the model forecast for this coming Wednesday evening one last upper level low pressure wave will be moving toward Star Valley as the strong upper ridge builds toward the West Coast.

500 mb level forecast for Wednesday evening 2/1/2012

The threat of light snow will persist across Star Valley until this final upper trough moves southeast of our area by Thursday morning. Total snowfall for the period Monday afternoon until Wednesday night could add up to 2-4 inches in the Valley with upwards of a foot in favorable nearby mountain locations.

Then the strong ridge of high pressure builds across much of the northwestern States and shuts down the active weather for an extended period. The 500 mb forecast for next Sunday strongly supports this idea of no snow after about Wednesday night for an extended period.

500 mb Forecast Sunday 2/5/2012

With this type of pattern the sensible weather in Star Valley will be dominated by strong nighttime inversions which will have a difficult time dissipating in the afternoon as the sun angle is still too low. Result will be minimums on the valley floor dropping to near or below zero with afternoon highs in the probably not rising to freezing. This will result in rather marked differences with those areas that remain above the inversion, such as the mountainous regions and higher valley locations such as Star Valley Ranch and the far end of the Valley south of Smoot where elevations are near 7000 feet. Here daytime maximums should be well above freezing and remain above zero at night.

The higher sun angle the first week in February compared to the extended stagnation period experienced in December should be a little more effective in daytime warming keeping temperatures above the cold ones in December.

Excellent Weekend Ahead

2012-01-26T08:47:00.000-08:00

About 6 hours of snow will accompany a fast moving upper trough and strong jet stream Thursday afternoon and evening across Star Valley. It should add another 2-4 inches to the current snow pack. While flurries could continue through the night, high pressure and a drier northwesterly flow will lead to one of the better weekends of the Winter. With several inches of new snow on the now substantial snow-pack, outdoor winter sports should be enjoyed under lots of sunshine, particularly Saturday.

The next system will be approaching Star Valley later Sunday into the first of next week. Thus clouds could be on the increase Sunday, however, any new snow should hold off until Sunday night or Monday.

With the clearing skies, overnight temperatures will drop to around zero or below Saturday and again Sunday morning. Inversions will likely develop and keep the valley locations well below freezing. However, winds will be light and sunshine abundant, particularly on Saturday.

The long range forecast models continue to bring air off the Pacific into Star Valley, rather than out of the Arctic regions of Northern Canada. Bitterly cold air should not be a threat to this area for the foreseeable future.

The latest extended temperature and precipitation forecasts from the Climate Prediction Center certainly support this idea.


Temperature Forecast Feb 2-9 2012

Precipitation Forecast Feb 2-9 2012

Weekend Storm, the Good and the Bad

2012-01-23T15:39:00.000-08:00

The weather system which resulted in the large amounts of snow and even rain in Star Valley at the end of last week, provided the energy for a Mid Winter tornado outbreak in the southern states late Sunday and early Monday.

There were reports of a couple dozen tornados with the most deadly occurring in the early morning hours in central Alabama. These tornados were generated by intense supercell thunderstorms. Following are a couple images from early Monday morning of both the reflectivity and velocities detected from the Birmingham Al Doppler radar.


Radar images at 5:05 am CDT 1/23/12

The top image shows a classic hook signature with an associated very tight velocity couplet on the bottom.

There were reports of at least 2 fatalities and over 100 injured with these early morning storms in Alabama.

A much more positive result from the same storm system was the culmination of a very wet week in Star Valley. Below is a figure showing the dramatic improvement in the snow pack in the Salt Range at the Willow Creek Snotel site.

This brings the snowpack almost up to normal after such a poor start to the winter season.

The same storm brought copious amounts of rain and snow to nearby Salt Lake City area. While the snow was very beneficial in the mountains, hazardous driving conditions resulted from the heavy snow on the hilly roads in Bountiful Utah. The attached video attests to this!

Snow Totals As of Friday PM

2012-01-21T16:00:00.000-08:00

While another storm has dumped additional very wet snow mixed with rain on Star Valley Saturday, Riverton WFO has provided an excellent summary of the snow totals across Western Wyoming through Friday afternoon. Below is a listing of locations by County.

County	Station Name	Snowfall
Big Horn	Bone Springs Divide Snotel	14
Big Horn	Shell Creek Snotel	9
Big Horn	Bald Mountain Snotel	6
Fremont	Burroughs Creek Snotel	34
Fremont	South Pass Snotel	21
Fremont	Castle Creek Snotel	21
Fremont	Brooks Lake Lodge	19
Fremont	Cold Springs Snotel	12
Fremont	Hobbs Park Snotel	10
Fremont	Little Warm Snotel	9
Fremont	Deer Park Snotel	9
Fremont	Townsend Creek Snotel	7
Fremont	St. Lawrence Alt Snotel	3
Fremont	Dubois	1.5
Hot Springs	Owl Creek Snotel	9
Johnson	Cloud Peak Reservoir Snotel	13
Johnson	Soldier Park Snotel	12
Johnson	Little Goose Snotel	9
Johnson	Hansen Sawmill Snotel	9
Johnson	Bear Trap Meadow Snotel	3
Lincoln	Blind Bull Summit Snotel	54
Lincoln	Willow Creek Snotel	49
Lincoln	Indian Creek Snotel	44
Lincoln	Spring Creek Divide Snotel	43
Lincoln	Cottonwood Creek Snotel	35
Lincoln	Kelley Ranger Station Snotel	32
Lincoln	Salt River Summit Snotel	28
Lincoln	Blind Bull Summit	26
Lincoln	Box Y Ranch	24
Lincoln	Hams Fork Snotel	22
Lincoln	5 NNE Thayne	19
Lincoln	Alpine	18
Lincoln	1 SE Thayne	14
Lincoln	5 SSE Smoot	14
Lincoln	3 SE Bedford	13
Lincoln	Star Valley Ranch	13
Lincoln	1 W Smoot	8.5
Lincoln	Afton	6 to 8
Lincoln	Kemmerer	3.5
Lincoln	1 SW Kemmerer	1
Lincoln	Afton	0.5
Lincoln	La Barge	0.3
Natrona	Grave Spring Snotel	6
Park	Evening Star Snotel	38
Park	Beartooth Lake Snotel	35
Park	Younts Peak Snotel	31
Park	Blackwater Snotel	30
Park	Wolverine Snotel	21
Park	Kirwin Snotel	16
Park	Pahaska	13
Park	Marquette Snotel	8
Park	2 WSW Cody	1
Park	1 WNW Cody	0.8
Park	4 SE Cody	0.3
Park	Lamar Ranger Station	0.2
Park	5 ESE Cody	0.2
Sublette	Triple Peak Snotel	43
Sublette	Kendall Ranger Station Snotel	39
Sublette	3 NW Bondurant	34
Sublette	Larsen Creek Snotel	33
Sublette	Big Sandy Opening Snotel	33
Sublette	Loomis Park Snotel	32
Sublette	Pocket Creek Snotel	28
Sublette	East Rim Divide Snotel	26
Sublette	New Fork Lake Snotel	26
Sublette	Elkhart Park G.S. Snotel	25
Sublette	Bondurant	24.6
Sublette	Gunsite Pass Snotel	23
Sublette	Snider Basin Snotel	21
Sublette	Merna	14
Sublette	14 NW Pinedale	9.6
Sublette	Cora	9
Sublette	Daniel Fish Hatchery	6.5
Sublette	Pinedale	6
Sublette	13 SE Pinedale	2.6
Sublette	Boulder Rearing Station	1
Sublette	Pinedale	1
Teton	Grassy Lake Snotel	72
Teton	Phillips Bench Snotel	59
Teton	Jackson Hole-Rendezvous Bowl	45
Teton	Base Camp Snotel	44
Teton	Grand Targhee Snotel	42
Teton	Snake River Station Snotel	37
Teton	Togwotee Pass Snotel	33
Teton	Granite Creek Snotel	33
Teton	Jackson Hole-Raymer	31
Teton	Snow King Ski Area	29
Teton	Jackson Hole-Mid	28
Teton	3 SSW Wilson	28
Teton	Grand Targhee Ski Area	25
Teton	5N Hoback Junction	24
Teton	6 S Jackson	24
Teton	Togwotee	22
Teton	2 SW Teton Village	21
Teton	4 SSW Jackson	19.4
Teton	Gros Ventre Summit Snotel	19
Teton	Grand Targhee-Chief Joseph	18
Teton	Jackson	12 to 18
Teton	12 NE Jackson	17.5
Teton	Jackson Hole-Base	15
Teton	South Park	13
Teton	5 NW Jackson	11.5
Teton	6 N Jackson	10
Teton	1 NNW Alta	10
Teton	Kelly	8
Teton	8 E Moran	3.5
Washakie	Middle Powder Snotel	2
Yellowstone	Lewis Lake Divide Snotel	55
Yellowstone	Two Ocean Plateau Snotel	46
Yellowstone	Parker Peak Snotel	24
Yellowstone	Thumb Divide Snotel	20
Yellowstone	Snake River Ranger Station	20
Yellowstone	Sylvan Road Snotel	15
Yellowstone	Sylvan Lake Snotel	15
Yellowstone	Old Faithful Ranger Station	11
Yellowstone	Canyon Snotel	9
Yellowstone	Canyon Ranger Station	9
Yellowstone	Yellowstone East Entrance	8
Yellowstone	East Entrance Ranger Station	8
Yellowstone	Lake Ranger Station	2
Yellowstone	Tower Falls Ranger Station	2
Yellowstone	Tower Ranger Station	1.3
Yellowstone	Madison Ranger Station	1

Following are images of the Lincoln and Teton County reports along with the Yellowstone National Park.


Snowfall Totals Lincoln County January 18-20 2012


Snowfall Totals Teton County January 18-20 2012


Snowfall Totals Yellowstone NP January 18-20 2012

The winner was the Grassy Lake Snotel Site in the southwestern portion of Yellowstone NP with 6 feet!

While still below normal the storms have made a large impact on the big snow deficit of just a week ago as can be seen by the graphs below.


Grassy Lake Snotel Site

Of more interest to Star Valley would be the Willow Creek Snotel graphs.


Willow Creek Snotel Graphs

While still below normal, with the change in the storm track the outlook for a favorable water year is much improved.

More Snow To Come

2012-01-19T16:58:00.000-08:00

As expected Big Snows have occurred across Star Valley and much of Northwestern Wyoming and more is on the way. As of Thursday afternoon upwards of 3-4 feet have fallen in the Tetons with 2 plus feet in the Salt and Wyoming Ranges as well as in the valley around Jackson Hole and Hoback Junction. Lower portions of the Salt River Valley reported at least a foot with a little less further south in the Afton area. Below is a detailed map of snowfall amounts received thus far.

Temperatures warmed considerably to above freezing in much of Star Valley Thursday. Snow has temporarily mixed with or turned to rain. However more significant snow is expected tonight and early Friday ahead of the next disturbance moving rapidly east across the area.

Snow has already increased by this evening across the valley enhanced by the strong westerly winds of 50-60 mph that forecasts show at 700 mb or mountain top level.


700mb Forecast early Friday Morning 1/20/12

This will maintain snows with additional 6 or more inches of wet snow in the valley tonight with upwards of a foot in the nearby mountains.

As temporary high pressure ridging moves across on Friday snow should diminish possibly briefly ending as the westerly winds at mountain top level weaken to only 20 mph or so.


700mb Forecast Friday afternoon 1/20/12

The next system will again spread snow, likely heavy at times across Western Wyoming Saturday.

The models over the next 3 days are forecasting large amounts of precipitation again with between 1 and 2 inches of water content.

Model Precipitation Forecast Friday-Sunday 1/20-22/2012

With snow ratios of 10 to 1 this suggest that at least a foot is likely in the valleys upwards to 2-3 feet in the Tetons.

With the very fast jet stream now in place across the area, more storms are likely to affect Star Valley next week, but timing and intensity is difficult to anticipate at this time.

Big Snows Ahead

2012-01-17T15:01:00.000-08:00

The long advertised pattern change is imminent. The cold air that spread across Star Valley Monday will be replaced by a strong flow of moisture that originates from the Pacific. Snow will begin Tuesday night and pick up in intensity Wednesday. While the temperatures will be rising to near or slightly above freezing by Thursday, the precipitation is expected to remain snow with heavy accumulations now forecast.

By Thursday night accumulations on the valley floor could exceed a foot with upwards of two feet in the nearby mountains, including the Salt and Wyoming Ranges The Tetons could see even greater totals of 3-4 feet.

Systems will be moving rapidly across the area in the very strong Polar Jet making it difficult to time the periods of increased snowfall rates after Thursday. However, snow will continue to fall through the coming weekend with additional significant amounts likely.

Below is a graphic with the forecast of snowfall totals by Friday morning.

Snowfall Totals Forecast by Friday Morning 01/20/12

There will be a sharp drop off in snowfall in the downslope areas of Central Wyoming where very strong winds will be the greater risk.

Big Boost to Snow Pack Coming

2012-01-15T13:59:00.000-08:00

The first Water Supply Forecast for 2012 based on the current below normal snow pack has been issued by the Riverton Forecast Office.


Wyoming Water Supply Outlook issued January 11, 2012

The Salt, Greys and Snake Rivers are all forecast to be below normal based on the current snow pack. Currently snow packs are running just a little above 50 percent of normal.

However, a major change in the jet stream pattern, that has maintained the dry and cold pattern, is expected to provide a significant boost to the snow pack and potential water supply for the remainder of January.

Several fast moving systems will be tracking across Star Valley beginning tonight. This first system will primarily be ushering in a cold air mass dropping temperatures 20-30 degrees from this afternoons highs in the 40s to teens on Monday. Gusty winds and snow will whip through Star Valley later tonight and Monday morning. However, limited moisture should preclude more than an inch or two in the valley with several inches in the nearby mountains.

After a brief respite Tuesday, the next of several fast moving disturbances will move from the Pacific Ocean across Star Valley accompanied by a very moist air mass and strong westerly winds.


500 mb forecast Tuesday Evening 01/17/2012

While timing of disturbances that will be embedded within the strong polar jet, the moist westerlies will be established by Wednesday, leading to an extended period of snow. Temperatures will gradually warm with precipitation possibly turning to rain by the end of the week in lower elevations.

The models are forecasting large amounts of precipitation.


Model Precipitation Forecast Wed-Sat Jan 18-21,2012

Snow totals in the mountains are likely to be measured in feet, ranging upward to 2-3 feet, with the greatest in the Tetons and substantial totals even in the mountains surrounding Star Valley. The valley floor should easily receive upwards of a foot and possibly even more if precipitation remains all snow.

Stormy the Last Half of January

2012-01-12T22:16:00.000-08:00

Confidence has increased in the numerical models forecast of a major jet stream pattern change. High pressure currently dominating the Star Valley region will weaken over the coming weekend. This will allow a strong Pacific jet stream and storm track to enter the Western U.S. Initially this will lead to a gradual modification of the cold air mass currently across the area along with increasing cloud cover over the coming weekend.

The first in what appears to be a series of strong upper troughs will spread snow across the region by late Sunday into Monday.


300 mb Forecast Sunday evening 01/15/12

The moisture available with this system is expected to be somewhat limited, thus snow amounts should not be excessive. At this time a few inches in Star Valley are possible with higher elevations somewhat greater by Monday morning.

The precipitable water content forecast for Sunday evening shows the limited moisture.


Precipitable Water forecast Sunday evening 01/15/12

However the jet stream continues to stream eastward from the Pacific Ocean across the Star Valley region bringing increasing amounts of moisture inland.


300 mb Forecast Tuesday Evening 01/17/12


Precipitable Water forecast Tuesday evening 1/17/12

Precipitable water amounts are forecast to increase dramatically by that time along and off the Pacific coast with resultant threat of significant snows developing, particularly in the mountains.

Systems will be moving rapidly with the strong jet stream, precluding any skill in timing the greatest threat of snowfall. However with the storm track/jet stream remaining across the region into the following weekend it would be expected that substantial amounts of precipitation, likely snow will occur over the next 7-10 days.

The models rather rough guess at the total amount of precipitation to fall over the next ten days,

Model precipitation forecast for 10 days ending Sunday 1/22/12

up to 2 inches along the western Wyoming border, including Star Valley. Thus snowfalls upwards of one of more feet would be possible in the valley and considerably more in the mountains north and east of Star Valley. This assumes the models have a reasonable handle on the developments and that much of the valley precipitation will be snow It will be a mild flow of air off the Pacific similar to the end of December, which could result in at least some rain in the valley and less snow.

Signs of A Return to Winter Snows Next Week

2012-01-10T09:31:00.000-08:00

The first 10 days of 2012 have been virtually snow free across Star Valley. Such is not the case in the towns of Valdez and Cordova Alaska, which have been buried under 10-15 feet of snow so far this winter


Photo from Valdez Alaska January 9 ,2012

There is an upper trough of low pressure that will be passing by mostly to the northeast of Star Valley tonight. This mornings 500 mb analysis locates the trough just moving southeastward toward the Northern Rockies.


500 mb Analysis Tuesday Morning January 10, 2012

By Wednesday evening this trough will deepen over the Plains and bring considerably colder air south into Star Valley.


500 mb forecast Wednesday Evening 01/11/12

While some light snow could move across Star Valley later this afternoon and evening, no accumulation of concern is expected. As cold high pressure moves out of Canada in the wake of the trough, skies will clear on Wednesday leading to a very cold night. Temperatures Thursday morning could be the coldest experienced thus far this winter. With clear skies and calm winds, coldest valley locations such as Auburn /Grover and possibly Thayne could drop to 15-20 below zero. Typically warmer locations, such as higher elevations of Star Valley Ranch, may not drop much, if any, below zero.

High pressure will cover much of the Intermountain West through the coming weekend. As has been the case much of the winter, strong valley inversions will develop and limit the amount of daytime warming, keeping temperatures well below freezing and nights below zero.

However, there are now signs that a pattern change is going to take place next week bringing an end to the snow drought. The jet stream and storm track will be shifting southward into the western states. The longer range models are still inconsistent on forecasting this change, but they do suggest that warmer air at least could begin to reach the valley floor raising daytime temperatures to above freezing by the first of the week.

Snow 2011 vs 2012

2012-01-06T12:51:00.000-08:00


Star Valley Snow Stake January 7 2011

Star Valley Snow Stake January 6 2012

Above are images of the Star Valley Snow stake taken a year apart. The weather station noted in the background of the 2011 photo was relocated to the roof of the Town of Star Valley Public Works Garage in August 2011 and can be seen at this link http://www.weatherlink.com/user/svrtown/.

Additionally the camera used in last year's image was located in the downstairs window of our home on the Ranch. It also was moved in August 2011 and now has an excellent view of the valley from the top floor of the Public Works Building. A current image from this camera can be seen at this link
http://216.128.229.102:443/image.jpg

The camera now viewing the snow stake is not quite the quality of the Stardot Camera that was moved to the Public Works Building but still provides a good view of the snow stake.

There was about a foot more snow on the ground in 2011(about double) than currently being observed, as can been seen from the images.

Looking ahead to snow possibilities there is good news and bad news. For those who rely on snow for winter sports it is bad news as the jet stream pattern remains unfavorable for any significant snowfall for the foreseeable future. For those who have enjoyed predominantly sunny, dry days it is good news. There should be several in the next week or so.

The key here is the term "foreseeable future". The computer models have continued to improve over the years but beyond a week still generally show limited skill when forecasting, particularly when it comes to precipitation.

One method of displaying forecast data is using meteographs. This particular meteograph was based on the computer model run from Friday morning, Jan 6 2012, for the next 180 hours or about 7 days and computed for Soda Springs, ID which is in fairly close proximity to Star Valley. Of particular interest is the lack of any precipitation being forecast for the next 7 days with only .01 for next Wednesday. Also, the temperature graph indicates no real cold weather which certainly can occur in mid January.

Meteograph for Soda Spring ID from Friday 1/6/12 to Saturday 1/14/12

How Long Will it Last?

2012-01-04T07:48:00.000-08:00

For the first week in January, Star Valley is enjoying beautiful weather. Temperatures Tuesday afternoon were above freezing in all areas of the valley. The strong temperature inversion which has been present much of the past month was still in place Tuesday with the coldest maximum of 32 at Etna, while at Salt River Summit the high temperature was 48 at an elevation, 2000 feet higher than Etna.

There should be two more days of exemplary conditions as high pressure covers the area.

The upper high pressure ridge remains strong as the model shows for Wednesday evening.

500mb Forecast Wednesday Evening 1/4/12

By Friday the ridge temporarily breaks down allowing a rather weak upper low pressure trough to cross Idaho/Wyoming.

500 mb Forecast Friday evening 01/6/2012

And then by the end of the weekend the upper high pressure ridge again moves toward our area.

500 mb Forecast Sunday Evening 01/08/12

By Friday cloudiness and scattered snow showers will spread across the region with the passage of the weak upper trough. However this should result in generally insignificant snow totals at best in the valley and possibly a few inches in the higher elevations.

The model forecast total precipitation through the coming weekend suggest the same outcome.


Total precipitation forecast Thursday-Sunday

The Climate Prediction Center of NOAA in their forecast for the month of January issued on 12/31/2011 suggests that the high pressure will break down and lead to more favorable conditions for significant snows.

For at least the first week of January this will not be the case and time will tell how accurate this forecast will be for the remainder of the month.

2011 Wet and Snowy in Star Valley!

2012-01-01T21:43:00.000-08:00

To surprise of no one who resides in Star Valley, 2011 will go down as very wet and snowy. While the official report from the Climate Stations in Bedford and Afton will not be available for a few months, there is a dedicated observer in the far southern end of the valley who reports the rain and snowfall on the Internet every morning.

The observer is located about 5 miles south of Smoot at an elevation around 7000 feet. This location is higher than much of the valley likely accounting for the somewhat greater precipitation totals.

For the year this station measured 32.05 inches of precipitation. The total amount of snow for the year was an impressive 241 inches.

Snow cover was noted from November 9 2010 until it finally completely melted on the last day of May of 2011. This was a total of 203 consecutive days of snow cover!

While this winter has so far started with less snow, snow has been on the ground since November 5th.

This data is reported every morning on the Internet site

http://www.cocorahs.org/

There are thousands of reports from around the USA entered every day on this site. In Star Valley the only other active observer is at my home in Star Valley Ranch. However since my record began last Spring an annual summary is not available for 2011.

Any one interested in becoming an official observer can find directions on the site. Also I would be happy to provide assistance if needed.

Second Storm Will Blast Star Valley Early Saturday

2011-12-30T16:24:00.000-08:00

The second of two storms will bring an end to the brief respite from the cold of December. One system brought significant precipitation to the western Wyoming mountains and valleys early Thursday. Due to the unseasonably warm air accompanying the system, Star Valley experienced more rain than snow with little accumulation on the valley floor. While total precipitation, as measured by the weather stations in the valley, ranged upwards of half an inch, only a inch or two of wet snow was observed. This was not the case in higher elevations above about 7000 feet with around a foot observed in parts of the Wyoming Range and from 1-2 feet in the Tetons. The following chart was produced by Riverton WFO showing the observed snowfall from the first storm.

Very strong winds were observed across the high country, with Mt Coffin in the Wyoming range reporting gusts to 134 mph Thursday morning.

Warm air continued to cover the area through Friday with afternoon temperatures into the mid 40s under quite a bit of late December sunshine.

Storm number 2 now moving through the Pacific Northwest will bring an end to the brief respite from winter cold. Rain and snow will spread across Star Valley, beginning later Friday evening, becoming all snow after midnight. The cold front will arrive prior to sunrise accompanied by strong, gusty winds and 2-3 hours of moderate to heavy snow. The snow should decrease to showers/flurries by later Saturday morning, however. cold air will drop temperatures to well below freezing during the afternoon. Given the rapid movement of the storms, snow totals should generally range from 3-6 inches with the greatest potential in the northern portion of the valley.

High pressure then builds into the area by New Years Day and will dominate into the middle of the first week of the New Year. This returns Star Valley to weather experienced much of December, cold nights with sunshine most days. Overnight temperatures will drop below zero in colder valley locations, then struggle to reach the teens during the afternoon, given the low sun angle this time or year.

The next chance of significant snow should not occur until after midweek.

Snows Coming

2011-12-26T22:34:00.000-08:00

The advertised pattern change is underway as the storm track which has bypassed Star Valley much of December will be providing a snowy end to the year. As can be seen on this evenings water vapor imagery a moist westerly jet is moving eastward across the eastern Pacific toward the Pacific Northwest.

Water Vapor Imagery Monday Evening 12/26/2011

The effects will be noticed beginning with increasing cloud cover holding temperatures well above the zero readings experienced much of the nights this month in Star Valley. Precipitation in the form of snow will commence during the daylight hours Wednesday It appears that intensities will pick up by Wednesday night and continue through Thursday and possibly Friday. Temperatures will warm to near and possibly slightly above freezing in Star Valley by Thursday. While precipitation will likely remain as snow, the warmer air mass should lead to a much wetter snow than that experienced so far this month. The Riverton Weather Forecast Office has indicated over a foot can be expected in the nearby mountains and possibly 6-12 inches in Star Valley with the heaviest amounts from Thayne to Alpine.

Snowfall forecast 12/28-29 2011

With the strong westerly winds, the snow will fall mainly over and west of the mountains of Western Wyoming. Downslope flow will result in little snow over much of central and eastern portions of the state, however winds will be strong and gusty.

The greatest amounts are likely over and west of the Tetons where by this weekend, new snowfall could be measured in feet, possibly up to 2-3.

The month long stretch of below freezing days could come to an end at Thayne E.S. during the next couple of days.

Cold, Clear Christmas Weekend, Followed by Moderation and Increasing Snow Potential

2011-12-23T22:25:00.000-08:00

A couple more cold nights this Christmas weekend, then Star Valley will see a change in the weather pattern the last week of 2011. As an illustration of how cold a month it has been thus far, Thayne Elementary has dropped below zero on 18 of the first 23 days of December, hitting a low of -15 on Friday morning. At the official observing site in Afton it dipped to -17 Friday morning with the temperature only rising to 3 above on a sunny afternoon. The strong inversion which has been dominant much of the month was very pronounced again on Friday. As an example Star Valley Ranch reached a high of 20 above around 10am. However the cold air over the valley deepened dropping the temperature to under 10 above by noon where it remained the rest of the afternoon.

Across the Salt Range at the Box Y Ranch after a morning low of 5 below the afternoon maximum was 27 above. The inversion in the narrow Grays River Valley is typically weaker than over the Salt and the mid winter sun can still provide good warming.

High pressure will assure Star Valley if not still cold, a beautifully clear Christmas weekend. With the fresh 2-3 inches of snow on Thursday, a White Christmas will prevail.

The expected major pattern change still looks on schedule for the final week of 2011. The storm track along with a moist westerly flow off the Pacific Ocean will become an increasing factor through next week. If nothing else the cold nights should come to an end by mid-week if not before as clouds provide a blanket over the valley.


300 mb Forecast Thursday Evening 12/29 2011

While the core of the strong polar jet should remain somewhat north of Star Valley, the moist westerly flow should provide periods of snow in the mountains and some snow or even rain in the valleys beginning mid week.

The model forecast of precipitation for this next week through Thursday suggest potential for significant snowfall in the mountains of Northwestern Wyoming, possibly as far south as Star Valley.


Model forecasted Precipitation Through Thursday evening 12/29/11

Fast Moving Storm to Affect Star Valley Wednesday followed by a Cold but Snow-Free Christmas Weekend.

2011-12-20T20:02:00.000-08:00

A fast moving upper level low pressure trough located over southern British Columbia Tuesday evening is expected to move quickly southeastward and provide a temporary return to winter weather over Star Valley on Wednesday. The water vapor imagery below shows not only this trough but a weaker one over Northern Baja California

Water Vapor Imagery Tuesday evening 12/20/11

This system will strengthen as it moves across southeast Idaho and western Wyoming during the day on Wednesday. Snow is expected to begin during the morning and as the system continues on southeast to Utah and Colorado, the snow will end from the north by Wednesday evening. The Riverton Weather Forecast Office has created a graphic with the expected associated snowfall amounts by Wednesday Night.

The greatest totals are expected in the higher elevations with 1-3 inches in Star Valley.

High pressure then provides a return to the conditions that have been experienced through much of December. Cold nights, with temperatures generally below zero, will prevail into the Christmas weekend. Minimums could possibly dip to 10-15 below by Thursday morning in coldest valley locations. It still appears that from Thursday until Christmas Day fair conditions will prevail with the potential for mostly sunny days.

However, the longer range models are now indicating that the high pressure that has been protecting Wyoming from storms much of December will be weakening next week. The jetstream is now forecast to start tracking from the Pacific eastward across Wyoming.

300 mb(30,000 ft) Forecast Tuesday 12/27/11

This change in pattern, if it materializes, will result in a more active pattern across Star Valley. Since it is almost a week away, the model predictability limitations preclude specifics at this time- although the snow potential could increase substantially in the last week of 2011.

December to Remain Abnormally Dry

2011-12-17T18:06:00.000-08:00

Persistent high pressure has been parked over the Star Valley area much of December. Result has been minimal amounts of snow and rather cold temperatures. It appears now that high pressure will be around at least through Christmas Weekend. The latest model forecast indicates that pressures will be above normal over the eastern Pacific Ocean, which will in turn force the storm track far to the north into Western Canada. This graphic is centered on Christmas Day.


Christmas Day Height Anomaly 500 mb Red indicates above normal heights, blue below

There will be a low pressure trough that will be passing off to the northeast of Star Valley on Wednesday, Some snow is possible with this system, but again amounts should be generally light.


500 mb forecast Wednesday December 21 2011

The longer range forecast through the remainder of the month do not hold out much hope for a significant snow storm the rest of 2011. While travelers will favor this outcome, skiers will not be pleased.

8-14 Day Outlook Precipitation Valid Dec 25-31 2011

The strong temperature inversion across the valley much of December is likely to persist. This will keep nights cold, near or below zero, and afternoon highs not likely reaching freezing. At Thayne Elementary the high so far this month has only been 26.

Cold But Little Snow First Half Of December

2011-12-15T12:23:00.000-08:00

So far December 2011 has been cold with little in the way of significant snow across Star Valley. Both Thayne and Etna Elementary School Weather Stations have now been providing reliable weather data since the fall of 2010. Following are data from the school stations.

Thayne                  Avg Max Avg Min
Dec 1-15 2011            19               -3
Dec 2010                    31              14
Jan   2011                   26                6
Feb 2011                    27               5

Etna                        Avg Max   Avg Min
Dec 1-15 2011             20                0
Dec 2010                     31    15
Jan 2011    26                  7
Feb 2011                     28                  5

The first 15 days of December's averages, thus far, are much colder than December 2010 as well as the normal temperatures for the month at the Beford Climatological station with a maximum of 28 and minimum of 6. Additionally, both stations are well below those observed last January and February.

The coldest morning so far this month was the 6th when Thayne dipped to -14 and Etna -10. Minimums at Thayne ES have been below zero 12 mornings so far this month.

While still cold, the Star Valley Ranch station has recorded average maximum/minimums of 26 and 7 thus far in December. The only morning below zero was on the 6th when it dipped to -4.

A strong temperature inversion has been in place much of the month which typically keeps the valley floor much colder than higher elevations. Thus the higher readings at Star Valley Ranch which is 300-400 feet above the adjacent valley floor.

While the early Fall started out with several significant snows, high pressure has dominated across Star Valley so far in December with the storms tracking both north and south of much of southeast Idaho and Wyoming.

Snowfall so far this month at Star Valley Ranch has totaled just 7 inches, while the station south of Smoot has had just 8 inches.   The average snow for the month of December at the Bedford Climate station is over 30 inches. Storms are expected to continue bypassing Star Valley for the next several days, so any appreciable snow is unlikely. With the early fall storms the snow totals since Oct 1st are 58 inches at Star Valley Ranch and 61 inches at the station south of Smoot.

Pattern Change Over The Western States

2011-12-11T20:24:00.000-08:00

A significant change in the storm track is taking place over the Western States for the coming week. Star Valley has been protected from storms for much of December by high pressure. While the skies have been generally clear the valley temperature inversions have been pronounced,. In Star Valley this has resulted in continued cold conditions overnight with lows below zero and afternoon high remaining in the teens., In the Cokeville area afternoon highs have not climbed out of the single digits over the weekend. Not the case above the valley floor, as the station at Star Valley Ranch warmed into the middle 20s and reminded well above zero at night. And just to the east at the Box Y Ranch along the Greys River maximums have been near freezing.

The high pressure which has been protecting much of the west has broken down and a new storm track is being established well to the south of Star Valley across the desert southwest.By Monday evening a large low pressure center will have developed over Southern California.

300 mb Forecast Monday Evening 12/12/2011

While this system will bring considerable precipitation, rain in the valleys and snow in the higher elevations of the Southwest, it will have minimal effects on Star Valley for the next few days. In fact the increase in clouds with the southwesterly flow ahead of the low will tend to lessen the strong overnight cooling allowing temperatures to generally remain above zero for much of the week. Additionally afternoon highs will approach freezing even on the valley floor as warmer air mixes down with an increase in the winds aloft.

With regards to snow, chances will remain low until mid week. Additional disturbances will be moving inland at that time, however model forecasts continue to take most of the effects to the south of southeastern Idaho and western Wyoming. Some light snow will be possible most days after Wednesday but any major snow event seems unlikely through next weekend.

Strong Temperature Inversions and High Pressure with Little Snow for the Next Week

2011-12-07T22:27:00.000-08:00

High pressure has become well established over much of the Western U.S. and will dominate through the coming weekend. The storm track has shifted well to the north of Star Valley resulting in a rather stagnant weather pattern. Strong inversions have developed in Star Valley under the generally clear and calm conditions and only limited daytime heating this time of year. The results are that the coldest daytime temperatures are occurring on the valley floor with considerably warmer readings above the inversion in the higher elevations. As an example while the afternoon temperature in Afton was only able to rise to 10 above Thursday, after a morning low of -9, it warmed to near freezing at Salt River Summit at an elevation some 1500 feet above the valley floor after a morning low of plus 7.

Visual evidence of this strong temperature inversion can be seen, particularly around Afton at the top of the haze/smoke layer.

Once these inversions become established this time of year, they will require a breakdown of the current high pressure to increase the atmospheric mixing to remove them. The earliest this seems likely to occur will be early next week when a weakening upper trough of low pressure is forecasted to cross the area. Until then expect plentiful daytime sunshine, but continued cold conditions in the Valley. Warmer conditions will continue to be observed in higher elevations where in some cases the morning lows will be higher than the adjacent valley afternoon highs.

Snow flurries are likely this Wednesday night as a weak disturbance passes across the area, however no accumulation is expected. The next chance of any significant snow appears to be no sooner than the middle of next week.

How Cold Was It?

2011-12-05T08:33:00.000-08:00

Overnight cloud cover thinned/dissipated toward sunrise allowing a rapid temperature drop. In the Lower Salt River Valley clouds hung around longer and as a result minimums were only near zero. However, from about Thayne southward it cleared and was much colder. Following are the observed minimums in the valley this morning.

Auburn                -17
Afton             -13
Thayne ES           -8
Osmond ES          -8
Smoot -5
Etna ES           -1
Star Valley Ranch 2
Alpine                   3

Nearby it was:

Pixley south of Cokeville -21
Driggs ID                         -17

Cokeville                          -15
Jackson Airport                -13

In other areas clouds were not a factor and as a result it was much colder.

Old Faithful             -33
West Yellowstone    -35

and the coldest was a -41 at the Peter Sink Site which is located just south of Logan Summit Utah west of Bear Lake. This high elevation sheltered site is typically one of the coldest around.

Bitter Cold Monday Morning

2011-12-03T10:01:00.000-08:00

The cold northerly flow continues across Star Valley. Fast moving disturbances embedded in the flow will bring periods of clouds and light snow. One such system brought 1-2 inches Saturday night and another one is scheduled to drop southward and bring no more than an inch or two on Sunday.

Of more importance, this next system is going to be followed by very cold air, originating over Northwest Canada. Although this is still not a true Arctic air mass as temperatures this morning over the Yukon are generally above zero, the ingredients are coming into place to drop temperatures over Star Valley Sunday night to well below zero. Skies should clear in the wake of Sundays system and the combination of light winds and the cold air aloft will lead to ideal conditions for a very cold night.

It now appears that 10-15 below zero will be common in the valley locations by sunrise Monday, with the coldest locations dropping to 20 below or lower. The only areas that may be spared the extreme cold would be the communities above the valley floor such as Star Valley Ranch where it could go no lower than about 5 below.

Gradual moderation in temperatures will occur into the middle of the coming week, however they are expected to remain well below normal for the first week in December. The pattern remains unfavorable for a significant snowstorm in Star Valley, probably through the coming week.

Star Valley to Have an Extended Period of Below Normal Temperatures with Little Snow

2011-11-30T23:04:00.000-08:00

A major adjustment is taking place in the storm track/jet stream over a large portion of the U.S. and northeastern Pacific Ocean. The latest storm to move from the Pacific is affecting the southwestern states Wednesday night, bringing very strong and damaging winds to some sections of California.

Western Wyoming is now dominated by a cold northerly flow of drier air from Canada. As high pressure builds north into the Gulf of Alaska, this will put Star Valley under an extended period of possibly more than a week of reinforcing surges of cold air from Canada. With the storms tracking across western Canada and then southeastward...most of the snow will occur east of the Continental Divide.

This first chart shows the forecasted abnormally high pressure centered over the Gulf Of Alaska. The red contours in the chart are areas of higher than normally 500 mb heights, with blue contours indicating areas of below normal 500 mb heights.

500 mb Anomalies Sat 12/3/11

The models suggest that this pattern will persist as shown on the following chart displaying the same fields as the one above except for Wednesday of next week.

500 mb Anomalies Wed 12/7/11

This pattern will be characterized by only brief periods of clouds and light snow as disturbances pass through Star Valley. Much of the time for the next week will see only limited amounts of cloud cover allowing for nighttime temperatures to drop below zero, and afternoons remaining well below freezing.

Fortunately there is not a pool of Arctic air yet available in Canada, so even though the jet stream pattern will be favorable, a bitter cold air mass from the north is not expected at least into early next week. If the pattern persists, then the possibility of an arctic air mass invading Wyoming will increase.

Nevertheless conditions will be favorable for colder valley locations dipping to 10 below zero or lower Friday morning under clear skies.

December will Begin Cold in Star Valley

2011-11-29T18:04:00.000-08:00

A storm which can be seen with the water vapor imagery this evening over Vancouver Island will be the big weather maker over the interior west the next several days.


Water Vapor Imagery Tuesday evening 11/29/11

By Thursday morning this low is forecast to drop southward to the west of Wyoming into the desert Southwest. The computer models have been consistently forecasting this scenario for the past several days.


500 mb Forecast Thursday morning 12/1/11

Much colder air will then flow southward from Canada into Wyoming by Thursday in the strong north/northeast flow as the upper low heads toward Arizona.

This type of pattern with much of the upper low energy tracking west of Star Valley should limit the snow potential. At this time a couple inches are probably all that can be expected to fall over the valley by Wednesday night. While strong northerly winds will spread across Wyoming and down the upper Snake River Valley by Thursday morning, Star Valley will be protected by the Salt Range limiting both the wind and wind chill effect in contrast to other areas of Wyoming.An exception could be in the Alpine area where the Snake River Canyon will likely channel the stronger east winds.

As cold air pours southward Thursday, afternoon temperatures will struggle to reach 20 and by evening rapidly fall to near/below zero. With skies clearing by Thursday night below zero will be common with coldest Star Valley locations such as Auburn and Thayne could drop to 10-15 below.

While any additional snow other than flurries is unlikely, cold high pressure will dominate into next week.

The Riverton WFO has provided an excellent presentation how the incoming storm will effect Wyoming. This can be seen at:

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=riw&storyid=75650&source=0

Star Valley Ranch Weather Station Now Corrected

2011-11-28T08:30:00.000-08:00

The temperature at the Star Valley Ranch weather station which had been running about 12 degrees too cold since 11/23 is now displaying the correct reading.

Other Than Wednesday, a Quiet Weather Week is in the Offing

2011-11-27T16:08:00.000-08:00

Clouds began returning to the skies of Star Valley late Sunday afternoon. Overall it was a cool but very sunny weekend. Clouds are the forerunners of a rather weak disturbance which will be crossing mainly north of Star Valley tonight and Monday morning. While there is the possibility of a few snow flurries toward morning, the main effect of the clouds will be to provide an insulating blanket and keep overnight temperatures well above zero.

High pressure takes over again by Monday night leading to a very pleasant and generally sunny Tuesday. The next storm of interest is expected to be much stronger and approach the Pacific Northwest states Tuesday from the Gulf of Alaska. The following sequence of forecasted 500 mb Charts show the expected evolution of this system during the week.

Tuesday Evening

Wednesday Evening


Thursday Evening

If this model scenario verifies, which seems likely as several models are in close agreement, then Wednesday will be the stormy day of the coming workweek. Colder but generally fair weather returns as high pressure moves in and the developing upper low that effects Star Valley on Wednesday settles southward into the desert Southwest. It is still too early to determine the snow potential for Wednesday.

Very Strong Winds Friday, However Quiet Weather Ahead

2011-11-25T20:06:00.000-08:00

As expected a fast moving trough of low pressure intensified as it crossed Western Wyoming Friday afternoon, producing some very strong winds and briefly near blizzard conditions. Here is a list of strongest reported gusts Friday:

Mt. Coffin   108 mph (10,800 ft)
Jackson Hole Summit    72 mph (10,300 ft)
Alpine                           51 mph
Star Valley Ranch          50 mph
Thayne                          42 mph

This evenings 300 mb analysis(30,000 ft) clearing shows the strongest jet stream crossing the area from the northwest where winds were in excess of 130 mph at its core.

300 mb (30,000 ft) Friday Evening Nov. 25 2011

While actual new snow in the valley was generally less than 2 inches, the strong winds produced briefly near blizzard conditions.

Rapid clearing has occurred this evening as high pressure spreads across the area. As the winds diminish temperatures are falling. As of 9pm Thayne ES had already dipped to 7 above and by sunrise the coldest Star Valley locations likely will be at least a couple degrees below zero.

High pressure will dominate for the next several days with the next threat of any significant precipitation not expected until at least next Wednesday, if then. Here is a model depiction of the precipitation that is forecasted through next Tuesday.


GFS Model Forecasted Precipitation from Saturday until Tuesday.

Today's storm in Wyoming will become a big precipitation producer in the eastern U.S. Heavy storms will continue to hammer the Pacific Northwest coast northward into Canada. High pressure will protect our part of the country from any storm activity.

Fast Moving Storm Friday, Followed By Several Dry Days.

2011-11-24T12:50:00.000-08:00

Under mostly clear skies a strong inversion developed overnight across Star Valley. Dramatic differences in temperatures were observed this morning. Etna ES dipped to 13 and Afton 12. However, in places like the forested areas of Star Valley Ranch and Salt River Summit, above the inversion, low temperatures this morning were as much as 20 degrees warmer, barely dipping below freezing.

Warmer air has spread across Star Valley above the inversion on Thanksgiving Day. Surface temperatures have risen into the 40s above the valley floor such as at Star Valley Ranch, even as clouds thicken ahead of the next Pacific storm. However, as of early afternoon Etna ES, below the inversion, has yet to reach freezing. The next system currently in the Pacific Northwest will move rapidly eastward bringing at least some snow across southeastern Idaho and western Wyoming beginning after midnight. There could be brief moderate snow as the cold front crosses the area late tonight and Friday morning. The speed of the system is expected to limit accumulations to no more than a couple inches in the Valley and somewhat greater amounts in the mountains, particularly the Tetons.

Rapid improvement will occur by Friday afternoon as high pressure takes over. This will lead to a dry weekend continuing into the middle of the coming work week. The storm track shifts well to the north assuring a quiet end to what has been a stormy November.


Comparison of GFS and ECMWF 500 mb Tuesday afternoon 11/29/11

While there are considerable differences in the model solutions Tuesday, both keep the storm track to the north of the Valley. However, by late Wednesday/Thursday the ECMWF(European Model) suggests a return to stormy conditions while the GFS(Globel Model) keep the Valley high and dry.


Comparison of GFS and ECMWF 500 mb Wednesday afternoon 11/30/11

Star Valley Ranch Weather Station

2011-11-23T21:30:00.000-08:00

The Star Valley Weather Station is running about 10 degrees too cold. This will be corrected as soon as possible, but may not be until Monday as the Console is located in the Public Works building.

Pattern Change Leading to Drier end of November

2011-11-22T22:28:00.000-08:00

Star Valley/Western Wyoming for the first three weeks of November has been colder and wetter than normal. Over 3 feet of snow has fallen at Star Valley Ranch with a similar amount near Smoot at the upper end of the valley. The Numerical forecast models are in agreement that the storm track which has been through this part of the country will be shifting back to the north the rest of the month. With the exception of a fast moving low pressure system that will move through late Thanksgiving day and Friday, it now appears that high pressure will be in control for the remainder of November.

Wednesday and Thanksgiving day will finally see temperatures rise to near or above normal. Afternoon highs will be warming to 40 or higher with more sunshine than in the past few days. Friday will see a temporary return to cloudy with precipitation, likely in the form of snow. At this time it appears that several inches are likely in the nearby mountains, but valley totals should be no more than a couple inches.

500 mb Forecast Friday afternoon Nov. 25 2011

High pressure quickly takes control over the weekend with the likelihood of mostly sunny and dry days. With the clearing skies overnight temperatures will drop to single digits in the coldest valley locations. Valley temperatures will be slow to warm given the low sun angle this time of year, with warmer temperatures in the higher elevations such as nearby ski areas.

500 mb Forecast Saturday Evening Nov. 26, 2011

With the jet stream and storm track well to the north early next week, fair conditions should dominate. This time of year the substantial snow cover, under high pressure, will result in favorable conditions for overnight fog formation. This could temper the amount of warming in the valleys, particularly if the fog fails to burn off in the afternoon.

Storm Exits Star Valley-Thanksgiving Outlook Looks Good

2011-11-19T09:41:00.000-08:00

The latest storm has cleared Star Valley but a cold and unstable air mass remains. Mostly light snow showers will continue until this evening. New snow across the valley ranged from 6-8 inches with 8 inches at Star Valley Ranch. Here is a map of the Snowfall totals for the storm produced by Riverton WFO.

Total Snowfall Nov. 17-19 2011

The current 500 MB analysis shows the strong polar jet stream heading on to the east into the plains with a new jet approaching California


500 MB Analysis Saturday Morning 11/19/11

The greatest snowfall with this storm occurred over the mountains with between one and two feet falling in the Tetons and about a foot over the Salt Range.

As we move toward Thanksgiving Day the storm track is forecast to shift to the south of Star Valley with the next system now approaching the California coast .

500 MB Forecast Tuesday Morning 11/22/11

This system is weaker than the previous system that just moved across the area. Much of the precipitation will pass well south of Star Valley as this trough of low pressure moves east into the Central Plains by Tuesday.

While another trough of low pressure will be moving onshore along the west coast by Thanksgiving day, the primary area of precipitation should again remain south and west of the valley. Southwesterly flow across southeast Idaho/western Wyoming is likely to be rather mild but result in quite a bit of cloud cover along with chance of either rain or snow showers.


500 MB Forecast Thursday Morning 11/24/11

It now appears that any precipitation will have minimal impact on Thanksgiving travel in Southeast Idaho/Western Wyoming.

The graphic below is the forecast of total precipitation for the 4-day period Monday to Thursday this coming week. It should be a wet period for much of the west coast, but only scattered light amounts over the interior west.

Total Forecasted Precipitation 5AM Mon -5AM Thu

UPDATE ON THE POTENTIALLY HEAVY SNOWFALL IN STAR VALLEY

2011-11-17T07:52:00.000-08:00

The major storm system is still on track to move eastward across southern Idaho into Western Wyoming. Light snow is beginning this morning in parts of the valley and will continue and increase during the day. It now appears that the potential for heavy snow with accumulations of 6-8 inches or more could occur in the valley before diminishing Friday night when the colder air arrives. The nearby mountain ranges will likely receive well over a foot. Even greater amounts of snow, possibly upwards of 2 feet by Saturday morning will fall over the Teton Range and southwestern portions of Yellowstone National Park.

Given the nearly 2 day duration of snow the total depth is expected, as mentioned, to be substantial. Temperatures will remain near freezing in the valley until the strong cold front arrives later on Friday. With the front will come gusty winds and temperatures falling into the teens, with deteriorating driving conditions in the valley and all roads out of the area.

The weekend still appears to be cold, however significant snowfall should be over.

MORE SNOW ON THE WAY FOLLOWED BY A VERY COLD WEEKEND

2011-11-15T20:18:00.000-08:00

Wednesday will be another fairly quiet day weatherwise across Star Valley with still a chance of snow flurries similar to Tuesday. Big changes will be underway by early Thursday. A disturbance will be moving across the Pacific Northwest Wednesday and spread increasing precipitation across Star Valley beginning by Thursday morning. The 300 MB forecasted winds for Thursday morning show the strong jet stream heading toward Idaho and Western Wyoming.


300 MB FORECAST THURSDAY MORNING 11/17/2011

Temperatures with this system will remain near freezing in the valley, favorable for a rather wet snow. There could be several inches fall in the valley by Thursday night/Friday morning and higher amounts in the nearby mountains.

300 MB FORECAST FRIDAY EVENING 11/18/2011

On Friday a very cold upper level trough of low pressure moves eastward from the Pacific Northwest states, which not only will continue periods of snow, possibly heavy in the mountains, but spread the coldest air yet this Fall across Star Valley. The coldest air will arrive Friday night and by Saturday temperatures will remain in the low to mid 20s in the valley throughout the day.


300 MB FORECAST SATURDAY EVENING 11/19/2011

By Saturday evening the strong jet stream and upper system will have moved rapidly on to the east of western Wyoming, leaving Star Valley under a very cold air mass which will end any significant snow threat. Dependent on the amount of clearing that occurs, below zero temperatures are possible Sunday morning, at least in the typically coldest valley locations nearer the Salt River such as Auburn, Thayne and Etna.

Looking ahead to the first of the coming work week, it looks like high pressure will dominate with still cold nighttime temperatures, possibly below zero, and a slow climb in afternoon readings. However there is potential for fog forming in the valley which would limit the heating potential in the afternoon.

CLIMATE

2011-11-14T07:43:00.000-08:00

The Climate link on Starvalleyweather.com is to the data from the official climatological station located just southeast of Bedford WY. The record for this site goes back to 1975 with very few missed observations. At this time just the current month data will be available from Starvalleyweather.com but plans are to eventually make the site more robust. The link to the official station data can be found at

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?wy0603

A VERY SNOWY WEEKEND IN STAR VALLEY

2011-11-13T18:32:00.000-08:00

Snowfall Totals in inches Nov 12-13 2011

As shown on this graphic from WFO Riverton large amounts of snow fell across all of Star Valley from early Saturday morning until Sunday afternoon. The greatest total observed was 19 inches at Star Valley Ranch followed by the 15 inches at the weather station just south of Smoot, 14 inches in Thayne and 12 inches in Alpine.

The snowfall resulted from two fast moving systems across Western Wyoming.The first included considerable wind at higher elevations Saturday morning. There was temporary afternoon clearing as seen from this photo in Star Valley Ranch.

At the same location on the Ranch this picture was taken Sunday morning where an additional 10 inches had fallen overnight!

The pattern that has resulted in this sudden change over the weekend is still in place as can be seen on this evenings water vapor imagery.

Water Vapor Image Sunday Evening Nov 13 2011

A broad area of moisture extends from the Gulf of Alaska southeastward across the Pacific Northwest and pointed toward western Wyoming. What this implies is that while the snow has generally stopped across Star Valley Sunday evening, additional fast moving but somewhat weaker upper disturbances while continue the potential for periods of generally light snow into Tuesday. Another 1 or 2 inches is possible but it appears that another bout of heavy snow seems unlikely.

By Wednesday high pressure will temporarily diminish or end any snowfall threat. It does appear that a major change in the large scale weather pattern will take place by the end of the work week increasing the potential for another significant storm affecting Star Valley/western Wyoming.

500 MB Forecast Saturday Nov. 19 2011

This is a model forecast depicting the development of a large scale upper level low pressure trough across much of the Western States. Since it is still 5-6 days away, the reliability of these forecasts are somewhat limited but there is sufficient confidence to expect the threat of winter weather conditions across much of the area from the Rockies westward including Star Valley.

Big Changes this Weekend Continuing into Next Week

2011-11-10T22:47:00.000-08:00


500 MB Noon Saturday 11/12/2011

After one more day on Friday of cool but pleasant weather, a fast moving storm will sweep across Star Valley Saturday morning. This system is a spin off from the massive storm that slammed Western Alaska Wednesday. It was one of most powerful storms in that part of Alaska in the past 40 years. The system which will move from the Gulf of Alaska southeastward into the Pacific Northwest early Friday will bring a strong cold front across the southeastern Idaho/western Wyoming area Saturday morning.

Snow levels will quickly drop to the valley floor Saturday morning with heavy snow for a couple hours with and just behind the front. The strong westerly flow will lead to the greatest snowfall along the north-south mountain ranges including the Salt and Tetons. Snowfall amounts will be greatest north of the Snake River with 4-8 inches in the mountains. It appears that 2-4 inches will be possible across Star Valley. Gusty winds will accompany the front and combined with the snow could lead to adverse traveling conditions, particularly across Teton Pass.

While the storm system will be moving quickly to east of the Valley by Saturday afternoon, a strong west to north flow will support an extended period of extensive cloud cover and periods of snow. By the middle of next week substantial amounts of snow could have accumulated in the mountains. and possibly in Star Valley as well.

Storm Track Remains To The South

2011-11-06T21:28:00.000-08:00


250 MB 39,000 feet Monday Oct 31 2011

250 MB 39,000 feet Sunday Nov 6 2011

A dramatic change in the jet stream and storm track took place this past week across much of the United States. Storms which were moving from well north of Star Valley then southeastward into the Central U.S. are currently moving across the desert southwest with only limited effects this far north.

It has been a seasonably cold and winter like weekend across the Valley with snow amounts ranging generally from 3-5 inches with the greatest two day total of 6 inches at Star Valley Ranch.

The pattern for this coming week will favor dry and generally fair weather as high pressure develops eastward across the western states. Again the jet stream will shift southward toward the weekend and bring the primary storminess to California and the desert southwest.

Forecasted 250 MB 39,000 feet Friday Nov 11 2011

Cloudiness over the weekend should be diminishing Monday, leading to at least some sunshine by afternoon. More sunshine is likely from Tuesday into Thursday as high pressure dominates the intermountain region. However with little wind at least until toward the weekend, nighttime temperatures will be quite cold, particularly with the limited cloud cover. Some of the colder valley locations will likely drop to the high single digits, possibly as early as Tuesday morning. The low sun angle and snow cover will limit the amount of daytime heating with afternoons remaining near freezing at least through Wednesday. As a result it could be even colder Wednesday morning with near zero possible in coldest spots.

Later in the week warmer air will begin to spread across the area leading to afternoon highs possibly into the 40s. Snow chances appear limited until the weekend when the storm off California begins to move eastward into the desert southwest. Again as occurred this weekend, it appears that the greater impact should remain well south of Star Valley.

ABOUT

2011-11-06T16:18:00.000-08:00

StarValleyWeather.com is the combined creation of three Johns. While the idea began with me, John (Jack) Hales a retired Severe Storms Forecaster who now resides in Star Valley Ranch, the actual development of the web page was the work of John Hart(current Severe Storms Forecaster in Norman OK at the Storm Prediction Center and John Hales the son of Jack who does web development for a living and resides in the Phoenix AZ area.

The primary goal of the web page is to provide the residents of Star Valley and its surroundings, along with any visitors or interested persons, one stop shopping for all the weather information they may need for a myriad of purposes.

Star Valley, due to its location with respect to several mountain ranges and in the path of many of the storms that cross the country along with its rather high elevation, poses a real challenge to anyone attempting to forecast its weather.

Knowing that I (Jack Hales) would be retiring to a home we built in Star Valley Ranch, and with a life long passion for the understanding of weather, I was able to aid in the establishment of three weather stations in Star Valley in 2010. They are located at Thayne and Etna Elementary schools as well as in the Town of Star Valley Ranch. They have provided more or less a continuous weather record since the Fall of 2010. The stations are built by Davis Instruments and have been and continue to provide their data online.
A primary purpose of the weather stations at the schools is to stimulate student interest in not only weather, but science in general. The school stations were funded by the Student Loan Fund of Idaho. All Three stations observe temperature, humidity, winds, pressure and both frozen and liquid precipitation. The Thayne Station has additional sensors that measure soil temperature and moisture at three depths: just below the surface, 2 feet and 4 feet deep. The Thayne station also measures both solar insolation and UV levels.

There are several links on the Home Page pointing to areas of interest with regards to Star Valley Weather. The Weather Cameras Link is unique and has been under development by my son, John Hales for the past three years. There is a link on the many capabilities the site has with regards to viewing a large number of live web cams not only in the Star Valley, Western Wyoming area but many other regions as well. You are referred to the link for directions on how to use the site.

There are links to weather information including not only forecasts issued from the Weather Forecast Office in Riverton, WY but other types of more numerically derived prognostic tools. Also available are both radar and satellite data and surface observations.

One other area of interest is my weather blog. The blog will evolve with time. But the primary goal is to focus on weather forecasting and observing in and around Star Valley WY. It will provide a means of enhancing the flow of weather info, particularly during periods of hazardous conditions both winter and otherwise.

Changes in the Wind for Star Valley

2011-10-31T08:48:00.000-07:00

This coming week will see a changing weather pattern as the storm track shifts southward over the Western U.S. The first storm will be be sending a cold front across Star Valley today accompanied by some precipitation...particularly along and over the mountains. Precipitation should initially be in the form of rain in the valley, but the snow level should drop to the valley floor by this evening. Once the cold front moves onto the east, the accompanying upper trough of low pressure will be intensifying as it moves across western Wyoming overnight. This will continue at least some light snow over the valley through the night with several inches likely falling in the higher elevations of the Salt and Wyoming Ranges.

Even though it will be intensifying, the upper trough should move east of the valley, by mid day Tuesday with a diminishing snow threat and some clearing by afternoon. The colder air will keep temperatures in the valley in the 30s all day. Tuesday night high pressure and clearing skies will allow temperatures to drop into the teens.

After a cool but generally fair Wednesday and much of Thursday, a much stronger storm will be developing into the western states by later Thursday. This storm will spread a much larger area of precipitation in the form of snow across much of the northern Intermountain region including Star Valley. Heavy snow is likely with this system but at this time the primary threat area is still uncertain. It is possible it will move far enough to the south to place the area of heavy snow across northern Utah or even further south. However it is quite likely that at least a few inches could occur in Star Valley beginning late Thursday into Friday. This storm will be followed by even colder air that the one now approaching and Saturday morning could see single digits in the coldest valley locations if skies clear sufficiently.

Winter Weather Is In Sight

2011-10-29T15:46:00.000-07:00

Since the early season heavy snow 3 weeks ago, the pattern for Star Valley has been generally dominated by high pressure and little in the way of active weather. In the wake of the storm system earlier this week that ushered in the coldest air of the fall, the pattern into the first of the week will be controlled by a storm track remaining north of Star Valley.

However the longer range forecast models are now indicating a major change to the jet stream location by the middle of the coming week. Initially a trough of low pressure will move through the Great Basin by later Tuesday with most of the precipitation moving through Nevada into Utah to the south of Star Valley. Then by Thursday a fair but cool day will prevail. The longer range forecast models are now indicating a much stronger and potentially significant Winter Like Storm will develop across southern Idaho/Nevada into Utah by early Friday. This storm has the potential for spreading widespread snow to the valley floors...including the lower elevations of Idaho and Northern Utah during the day Friday, impacting travel conditions in most routes out of Star Valley

Cold Air Arrives on Schedule

2011-10-26T07:34:00.000-07:00

A cold front moved across Star Valley early Tuesday as expected with little in the way of precipitation. The only measurable was .01 at Star Valley Ranch early Tuesday morning. However there was some snow in the Salt Range as both Willow Creek and Cottonwood Creek Snotel sites recorded about .10 in the form of snow which was visible on the Osmond ES Cam Tuesday morning above about 7500 feet.

Under clear skies and calm winds temperatures this morning dropped to the coldest of the fall. The lowest reported in the valley was at both Etna ES and Thayne ES with 14 and Star Valley Ranch was the warmest at 19.

While the cold front was generally dry in far Western Wyoming, significant snow has fallen in the east. As of this morning there has been as much as 9 inches reported in the Cheyenne area.

A generally fair weather pattern will set in across Star Valley the next several days. While nights will continue seasonably cold, daytime temperatures will slowly moderate. By Friday afternoon will be back into the 50s and likely change little into the coming week. Little in the way of precipitation is now expected at least through the weekend.

Indian Summer Comes to an End Tuesday In Star Valley

2011-10-23T19:23:00.000-07:00

After another unseasonably warm late October Day on Monday across Star Valley a cold front crossing the Valley Monday night will usher in a markedly cooler air mass on Tuesday. Daytime temperatures on Monday in the 50s will have a difficult time of rising above the low 40s Tuesday and remain in the 30s much of Wednesday. Most of the rain and snow with this system will likely remain to the north of Star Valley, however some light/snow could occur early Tuesday behind the cold front, most likely from the Narrows north as the cold front moves through. Any accumulation would likely be confined to the higher Salt and Wyoming Ranges, and even then only amount to an inch or so.

The greatest effect will be the colder air, officially ending the growing season across all of the Valley. By Wednesday morning the coldest regions of the valley will drop into the teens and well below freezing even in the typically milder locations such as Star Valley Ranch.

Later in the week high pressure will provide generally dry but cool conditions with a slow daytime warming trend.

FORECAST

2011-10-15T06:47:00.000-07:00

The FORECAST Section contains not only the latest Star Valley Zone Forecast produced by the Riverton WFO but the AFD(area forecast discussion) which is a meteorological reasoning that the forecast was based on. The Zone forecast is updated by the Riverton WFO as needed.

There is much more to the FORECAST Section than the products issued by Riverton WFO. Below the AFD is the latest 72 hour MOS(model output statistics) produced by the GFS(global forecast system) model. Jackson (JAC) is the closet site to Star Valley that the MOS forecast is produced. Additionally an extended GFSX MOS Forecast that extends out for 7 days is also included for JAC.

On the right side of the FOR ECAST page from top to bottom are:

--Current Visible satellite loop centered over the Northern Intermountain region. The loop is 2 plus hours long.

--Composite radar imagery loop. Left clicking on the loop will bring up the latest image overlaid with surface plots.

--Loop of PIH WSR-88D reflectivity image. Loop is around 45 minutes in length. Left clicking on the loop will bring up the complete radar menu among other options permitting the access of other radars.

--The most powerful diagnostic section available on the Star Valley Weather Page. Left clicking accesses the Storm Prediction Center(SPC) Hourly Mesoscale Analysis. There is a myriad of choices in selecting diagnostic fields which can be used forecasting not only convection including severe thunderstorms, but winter and fire weather conditions.. There is extensive helps built into the page. Also any questions I will be glad to try and provide an answer through the comment section.

While the area is centered over the Northwestern portion of the CONUS, it can be shifted to other areas along with a National area as well.

--This is the sounding section. Left clicking on the map of available soundings will by default bring up the plot of Norman OK. However any of the other soundings can be selected by left clocking on the star over the location. The soundings closest to Star Valley are SLC, BOI, and RIW. Soundings for the previous 7 days can also be selected. Again there is an extensive help menu provided on the page describing all the computed parameters from the sounding. Additionally any questions can be addressed on the comment section.

Where is the Sun?

2011-10-14T10:36:00.000-07:00

The forecast for Star Valley the past couple of days has called for mostly sunny. Anyone in the valley knows that there has been very little in the way of sunshine on Thursday and so far today. As with most of the weather that effects Star Valley, the mountains play a big role. In this case even though Idaho Falls and Pocatello have been enjoying lots of sunshine, the lift from the Caribou and Salt Ranges has continually developed cloudiness. To see this process in action go to the Web Camera page and build a several hour loop off the first cam looking out over the valley. The processes that are maintaining the cloud cover over the valley are quite evident. This can also be seen on the Forecast page and the visible loop over the area.

Current Conditions

2011-10-12T22:40:00.000-07:00

There are three options under Current Conditions, Temperatures, Winds and Rainfall. The plot is centered over Star Valley. Sources of the data are varied and in some areas overlap making it difficult to see all the stations. Rolling the mouse across the data will pop up a source id. The listing below the graphic is of all the stations that are displayed.

The plot is updated every 15 minutes. Rainfall totals are for the 24 hours ending at data plot time.

Weather Cameras

2011-10-10T09:17:00.000-07:00

The Weather Camera is a link to the site www.halescamvideo.com that was developed by John Hales as a Christmas Gift to me(his father) in 2008. While John provides any technical needs, I am the site manager and maintain quality control of the Cams on the site.

At any given time there could be as many as 90 web cams displayed. The criteria used to determine the display of a camera are:

1. Quality of the image.(StarDot Cameras much preferred).

2. Frequency of updates. (ideally every minute)

3. Proximity to Star Valley WY

4. View of the sky.

5. Reliability

Current Features

Left click on the image will provide a larger current image

The cursor at the top of each cam will open up the control menu for that particular cam.

Left click on the minutes option(30 60 120 180 300) will build a loop of that length in time.

Left click on the info (i) button and it will bring up a google map centered on the webcam location. Additionally it will display the latest weather observation and identifying the location of the observation.

There is also a radar option which when turned on will display the current composite reflectivity product from the NWS

Clicking on the + will open up a looping option. At least 3 days are available in the archive for all cams. Selecting the date/time and looping length in minutes will rebuild a loop.