Sunday, November 19, 2017

Thanksgiving Weekend Weather

A return to clouds and precipitation is expected across Western Wyoming early this coming week as very moist air spreads eastward from the Pacific.  However as the weeks progresses the  air mass is expected to dry leading to a precipitation free and relatively mild Thanksgiving day.  In fact the further south you go the warmer it gets, with potentially record setting temperatures near 90F in the Phoenix Area.

The building of a large high pressure system aloft over the Southwest by mid week shifts the storm track mainly to the north of Wyoming.

500 MB Chart Noon Thanksgiving Day


                                        Forecast Maximum Temperatures for Thanksgiving Day

Warm conditions will prevail much of the Western States on Thanksgiving with the cold weather affecting much of the East.

The large high pressure continues to dominate the Wyoming and Western States through the Thanksgiving weekend.

                                         500 mb forecast for Noon Sunday November 26  2017

This will maintain a mild to warm and dry weather pattern through the Thanksgiving Day Weekend from Wyoming south  to Mexico with the wet weather continuing to affect the Pacific Northwest and  cold in the East.

                               Forecast Precipitation for next Saturday and Sunday, November 25-26 2017

Saturday, November 18, 2017

Snow Storm Totals Western Wyoming

Saturday morning view of Afton from West Hills


Public Information Statement
National Weather Service Riverton WY
1220 PM MST Sat Nov 18 2017

A storm system produced some heavy snow in the western Wyoming
mountains Thursday and Friday. Snow also occurred at the lower
elevations of western Wyoming Friday. East of the divide, snow
showers occurred Friday and Friday evening.  Below are the latest
snowfall totals through 1100 AM MST Saturday morning. This is the
final snowfall report for the event.

Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.

SNOTELs (Snow Telemetry) are remote sensing sites in the mountain
watersheds.  Snowfall data from SNOTELs are estimated based on snow
water equivalent.

Location                              Snowfall
Lincoln County...
 Blind Bull Summit...                22 inches.
 Blind Bull Summit Snotel...         16 inches.
 Spring Creek Divide Snotel...       15 inches.
 Commissary Ridge...                 15 inches.
 Indian Creek Snotel...              13 inches.
 Willow Creek Snotel...              10 inches.
 Hams Fork Snotel...                  7 inches.
 Box Y Ranch...                       7 inches.
 Salt River Summit Snotel...          6 inches.
 Kelley Ranger Station Snotel...      6 inches.
 Fossil Butte...                    5.3 inches.
 Cottonwood Creek Snotel...           4 inches.
 5 NNE Thayne...                      4 inches.
 3 SE Bedford...                      3 inches.
 5 SSE Smoot...                       3 inches.
 Star Valley Ranch...                 2 inches.
 2 SE Thayne...                     1.5 inches.
 Afton...                             1 inch.

Teton County...
 Jackson Hole - Raymer...            24 inches.
 Jackson Hole - Rendezvous Bowl...   23 inches.
 Jackson Hole - Mid Mountain...      21 inches.
 Togwotee Pass Snotel...             18 inches.
 Phillips Bench Snotel...            16 inches.
 Grand Targhee - Chief Joseph...     15 inches.
 Togwotee Mountain Lodge...          15 inches.
 Grand Targhee Snotel...             14 inches.
 Grassy Lake Snotel...               13 inches.
 Gros Ventre Summit Snotel...        12 inches.
 Base Camp Snotel...                 10 inches.
 Snake River Stn Snotel...            9 inches.
 3 SSW Wilson...                    7.5 inches.
 Darwin Ranch...                    6.7 inches.
 Snow King...                         6 inches.
 Moose...                           5.3 inches.
 1 NNW Alta...                        4 inches.
 Snow King Ski Area...                4 inches.
 Jackson Dam...                     3.6 inches.
 Jackson Hole - Base...               3 inches.
 5 NW Jackson...                      2 inches.
 3 NNE Wilson...                      2 inches.
 Jackson...                           1 inch.
Big Horn County... Shell Creek Snotel... 3 inches. Bald Mountain Snotel... 3 inches. Bone Springs Divide Snotel... 3 inches. Powder River Pass... 2 inches. Fremont County... Brooks Lake... 21 inches. Hobbs Park Snotel... 15 inches. Deer Park Snotel... 13 inches. South Pass Snotel... 13 inches. Burroughs Creek Snotel... 9 inches. Little Warm Snotel... 6 inches. Townsend Creek Snotel... 4 inches. Cold Springs Snotel... 3 inches. St. Lawrence Alt Snotel... 3 inches. Castle Creek Snotel... 2 inches. Dubois... 1.5 inches. Jeffrey City... 1 inch. Riverton... 0.7 inches. 2 W Riverton... 0.5 inches. Riverton Airport... 0.4 inches. Hot Springs County... Johnson County... Cloud Peak Reservoir Snotel... 10 inches. 17 NNW Kaycee... 5 inches. Hansen Sawmill Snotel... 5 inches. Little Goose Snotel... 4 inches. Soldier Park Snotel... 4 inches. 4 SSW Buffalo... 3.3 inches. Bear Trap Meadow Snotel... 3 inches. 13 SSE Buffalo... 3 inches. Buffalo... 1-1.5 inches. 7 NE Buffalo... 0.6 inches. Natrona County... Reno Hill Snotel... 10 inches. Casper Mountain Snotel... 8 inches. 5 SSW Casper... 3 inches. 1 S Casper... 2.5 inches. 2 S Casper... 2 inches. Casper Mountain... 2 inches. Grave Springs Snotel... 2 inches. 11 WSW Casper... 1.5 inches. 4 WSW Casper... 1.3 inches. Casper Airport... 1.2 inches. Casper... 0.5-1.0 inches. Powder River... 0.5 inches. Park County... Blackwater Snotel... 13 inches. Younts Peak Snotel... 12 inches. Kirwin Snotel... 10 inches. Beartooth Lake Snotel... 10 inches. Evening Star Snotel... 7 inches. Wolverine Snotel... 5 inches. Marquette Snotel... 5 inches. Pahaska... 4 inches. Timber Creek Snotel... 3 inches. 2 WSW Cody... 3 inches. Cody... 2.5 inches. 4 SE Cody... 0.2 inches. Sublette County... Triple Peak Snotel... 13 inches. Loomis Park Snotel... 13 inches. Gunsite Pass Snotel... 11 inches. 26 NNW Pinedale... 8.5 inches. East Rim Divide Snotel... 7 inches. Snider Basin Snotel... 6 inches. Larsen Creek Snotel... 6 inches. Big Sandy Opening Snotel... 6 inches. 14 NW Pinedale... 5.8 inches. Kendall Ranger Station Snotel... 5 inches. New Fork Lake Snotel... 4 inches. Pocket Creek Snotel... 4 inches. Daniel Fish Hatchery... 2 inches. Elkhart Park G.S. Snotel... 2 inches. Pinedale... 1.2 inches. Boulder Rearing Station... 1 inch. Sweetwater County... Green River... 1.4-3.5 inches. Rock Springs... 0.5 inches. Washakie County... Powder River Pass Snotel... 5 inches. Middle Powder Snotel... 2 inches. Yellowstone National Park... Two Ocean Plateau Snotel... 20 inches. Lewis Lake Divide Snotel... 17 inches. Thumb Divide Snotel... 12 inches. Parker Peak Snotel... 11 inches. Sylvan Lake Snotel... 8 inches. Sylvan Road Snotel... 8 inches. Canyon Snotel... 4 inches. Lamar Ranger Station... 0.3 inches.

Friday, November 17, 2017

Heavy Snow in the Western Wyoming Mountains

Busy Day at  Grand Targhee with the Fresh Snow


National Weather Service Riverton WY
1224 PM MST Fri Nov 17 2017


A potent winter storm continues to send a stream of Pacific moisture
into Far Western Wyoming. This snowy event is expected to persist
through this afternoon although more showery in nature. The
following are snow totals that have accumulated around the area thus
far.

Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.

Snotels (Snow Telemetry) are remote sensing sites in the mountain
watersheds.  Snowfall data from SNOTELS are estimated based on snow
water equivalent.

Location                              Snowfall 
Lincoln County...
 Blind Bull Summit...                20 inches.
 Spring Creek Divide Snotel...       15 inches.
 Indian Creek Snotel...              13 inches.
 Commissary Ridge...                 12 inches.
 Willow Creek Snotel...              10 inches.
 Blind Bull Summit Snotel...          8 inches.
 Hams Fork Snotel...                  7 inches.
 Kelley Ranger Station Snotel...      7 inches.
 Salt River Summit Snotel...          5 inches.
 Box Y Ranch...                       5 inches.
 Cottonwood Creek Snotel...           4 inches.
 Star Valley Ranch...                 3 inches
 5 SSE Smoot...                       3 inches
 1 SE Thayne...                       1 inch 


Teton County...
 Jackson Hole - Raymer...            20 inches.
 Jackson Hole - Rendezvous Bowl...   20 inches.
 Jackson Hole - Mid Mountain...      18 inches.
 Phillips Bench Snotel...            14 inches.
 Togwotee Pass Snotel...             13 inches.
 Grand Targhee - Chief Joseph...     12 inches.
 Gros Ventre Summit Snotel...        11 inches.
 Grassy Lake Snotel...               10 inches.
 Togwotee Mountain Lodge...           9 inches.
 Grand Targhee Snotel...              7 inches.
 Base Camp Snotel...                  7 inches.
 3 SSW Wilson...                    6.5 inches.
 Snow King Ski Area...                4 inches.
 Snake River Stn Snotel...            4 inches.
 Jackson Dam...                     2.5 inches.
 3 NNE Wilson...                      2 inches.
 Snow King...                         2 inches.
 5 NW Jackson...                      2 inches.
 Moose...                           1.8 inches.
 Jackson Hole - Base...             1.5 inches.
Big Horn County... Shell Creek Snotel... 2 inches. Powder River Pass... 2 inches. Bone Springs Divide Snotel... 2 inches. Bald Mountain Snotel... 1 inch. Fremont County... Brooks Lake... 16 inches. Hobbs Park Snotel... 15 inches. South Pass Snotel... 13 inches. Deer Park Snotel... 12 inches. Burroughs Creek Snotel... 9 inches. Little Warm Snotel... 5 inches. Townsend Creek Snotel... 4 inches. Castle Creek Snotel... 2 inches. Cold Springs Snotel... 2 inches. Dubois... 0.5 inches. Johnson County... Cloud Peak Reservoir Snotel... 4 inches. Bear Trap Meadow Snotel... 2 inches. Little Goose Snotel... 1 inch. Soldier Park Snotel... 1 inch. Hansen Sawmill Snotel... 1 inch. Natrona County... Reno Hill Snotel... 3 inches. Casper Mountain... 2 inches. Park County... Younts Peak Snotel... 10 inches. Beartooth Lake Snotel... 10 inches. Blackwater Snotel... 10 inches. Kirwin Snotel... 10 inches. Evening Star Snotel... 5 inches. Wolverine Snotel... 5 inches. Marquette Snotel... 3 inches. Timber Creek Snotel... 2 inches. Sublette County... Triple Peak Snotel... 13 inches. Loomis Park Snotel... 11 inches. East Rim Divide Snotel... 7 inches. 14 NW Pinedale... 6.5 inches. Snider Basin Snotel... 6 inches. Gunsite Pass Snotel... 5 inches. Big Sandy Opening Snotel... 5 inches. Larsen Creek Snotel... 5 inches. Kendall Ranger Station Snotel... 5 inches. Pocket Creek Snotel... 3 inches. New Fork Lake Snotel... 3 inches. Elkhart Park G.S. Snotel... 2 inches. Boulder Rearing Station... 1 inch. Pinedale... 0.7 inches. Sweetwater County... Green River... 0.2 inches. Yellowstone National Park... Lewis Lake Divide Snotel... 21 inches. Thumb Divide Snotel... 12 inches. Parker Peak Snotel... 11 inches. Two Ocean Plateau Snotel... 10 inches. Sylvan Lake Snotel... 8 inches. Sylvan Road Snotel... 8 inches. Canyon Snotel... 4 inches. Lamar Ranger Station... 0.3 inches.

Thursday, November 16, 2017

Winter Storm Warning Star Valley later tonight and Friday

Total Snow ending Noon Friday November 17, 2017


National Weather Service Riverton WY
1259 PM MST Thu Nov 16 2017

...Heavy Snow in many of the western mountains through
at least Friday afternoon...
...Heavy snow in the Star Valley late tonight through Friday
afternoon...
...Periods of snow developing in the Jackson Valley late tonight
through Friday afternoon...

.A strong storm system will impact the west through at least late
Friday afternoon. Expect snow in the mountains and a mix of rain
and snow in the valleys through this evening. A cold front will
move in tonight, dropping snow levels and bring the heaviest
period of snow of the storm for Thursday night and Friday. The
snow will be accompanied by gusty winds with areas of blowing
snow.


Star Valley-
Including the cities of Afton, Alpine, Star Valley Ranch,
and Thayne
1259 PM MST Thu Nov 16 2017

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 5 PM
MST FRIDAY...

* WHAT...Rain will change to snow after midnight with periods of
  heavy snow showers from early Friday through late Friday
  afternoon. Snowfall rates could be around an inch per hour on
  Friday. The northern part of the Star Valley will likely see
  the heavier snow amounts, especially around Alpine and along the
  west slope of the foothills. Snowfall amounts will vary from 4
  to 8 inches with locally higher amounts. The snow will be
  accompanied by strong southwest wind 20 to 30 mph and gusty.

* WHERE...Star Valley.

* WHEN...Midnight to 5 PM Friday.

* ADDITIONAL DETAILS...Be prepared for significant reductions in
  visibility at times. Travel will become difficult as this
  system develops.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions are expected. If you must travel, keep an extra
flashlight, food and water in your vehicle in case of an
emergency. The latest road conditions for the state you are
calling from can be obtained by calling 5 1 1.

Wednesday, November 15, 2017

Winter Snow Watches and Warning out for Western Wyoming mountains and Star Valley






Total Snowfall ending Friday Night


National Weather Service Riverton WY
113 PM MST Wed Nov 15 2017

...Heavy Snow in the Tetons and Gros Ventre Ranges late tonight
through Friday...
...Moderate to heavy snow in much of the western mountains
Thursday through Friday...
...Heavy snow possible in the Star Valley late Thursday night
through Friday...

.A storm system will impact the west from later tonight through
Friday. Expect snow in the mountains and a mix of rain and snow
in the valleys through Thursday. A cold front will move in
Thursday night, dropping snow levels and bring the  heaviest
period of snow of the storm for Thursday night and Friday. The
snow will be accompanied by gusty winds with areas of blowing
snow.


Teton and Gros Ventre Mountains-
113 PM MST Wed Nov 15 2017

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 5 PM
MST FRIDAY...

* WHAT...Heavy snow expected. Travel will be very difficult to
  impossible, including during the evening commute on Thursday.
  Total snow accumulations of 1 to 2 feet, with locally higher
  amounts on the west side of the Tetons, are expected.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...Midnight to 5 PM Friday. The heaviest snow from this
  storm will likely be Thursday night into at least Friday morning
  when snowfall rates over an inch per hour are quite possible.

* ADDITIONAL DETAILS...Be prepared for significant reductions in
  visibility at times. Travel over Teton Pass will become
  increasing worse as this system develops.

Star Valley-
Including the cities of Afton, Alpine, Star Valley Ranch,
and Thayne
113 PM MST Wed Nov 15 2017

...WINTER STORM WATCH IN EFFECT FROM LATE THURSDAY NIGHT THROUGH
FRIDAY AFTERNOON...

* WHAT...Heavy snow possible. Plan on difficult travel conditions.
  Total snow accumulations of 3 to 6 inches are possible with
  higher amounts quite possible towards Alpine.

* WHERE...Star Valley
* WHEN...From late Thursday night through Friday afternoon.

* ADDITIONAL DETAILS...Significant reductions in visibility are
  possible. Most of the area will see rain developing tonight and
  continuing through Thursday. A strong cold front will push
  through Thursday night changing the rain over to snow. The snow
  could be quite heavy at times late Thursday night into Friday.
  The northern part of the valley could see snowfall rates of an
  inch an hour.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch means there is potential for significant
snow, sleet or ice accumulations that may impact travel. Continue
to monitor the latest forecasts.


Tuesday, November 14, 2017

Potent Storm moves into Western Wyoming by Thursday

The second and most potent storm of the week will be affecting Western Wyoming
and Star Valley beginning Wednesday night and continue into Friday.  Following is 
an animated water vapor imagery showing the next and more powerful system 
heading from the Gulf of Alaska toward the Pacific Northwest this afternoon.


In response to the next system, Riverton Forecast Office has issued a
Winter Storm Watch for the mountains of Northwest Wyoming beginning Wednesday 
Night.

National Weather Service Riverton WY
1259 PM MST Tue Nov 14 2017

...Heavy Snow in the Tetons and Gros Ventre Ranges late Wednesday
Night through Friday Morning...

.A new much more powerful storm system will impact the west
beginning later Wednesday night, continuing into Friday. Even
though the storm system is quite warm into Thursday, the mountains
will see all snow with rain or a rain and snow mixture in the western
valleys. A cold front will move in late Thursday, producing colder
temperatures and likely the heaviest period of snowfall of the
storm for Thursday night into Friday morning. The snow will be
accompanied by gusty to strong winds with areas of blowing snow,
especially as temperatures drop late Thursday into Thursday night.


Teton and Gros Ventre Mountains-
1259 PM MST Tue Nov 14 2017

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
FRIDAY MORNING...

* WHAT...Heavy snow possible. Travel will be very difficult to
  impossible, including during the morning commute on Thursday
  over Teton Pass. Total snow accumulations of 1 to 2 feet with
  locally higher amounts on the west side of the Tetons, are
  possible.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...From late Wednesday night through Friday morning.

* ADDITIONAL DETAILS...Significant reductions in visibility are
  possible as west to southwest winds of 20 to 40 mph blow the
  snow around.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch means there is potential for significant
snow that may impact travel. Continue to monitor the latest
forecasts.

Following is the forecast snowfall up until Thursday evening as issued by the
Riverton Forecast Office.



The next graphic is the computer model forecast of total snowfall ending Friday
evening.



Sunday, November 12, 2017

Two Weather Systems to Affect Star Valley this Work Week

Looking ahead  the work week will start out with another  fine weather day like was experienced Sunday with Monday's temperatures a few degrees warmer.  Then a couple of weather systems move from the Pacific across Wyoming and surrounding areas, the first Tuesday followed be a stronger and colder one by later Thursday into Friday.

The animated  infrared satellite loop from Sunday afternoon shows the first system approaching the coast of the Pacific Northwest. It will weaken  as it moves inland Monday while at the same time the  upstream trough over the Gulf of Alaska deepens southeastward.


This scenario can be seen in a series of 500mb charts.

500 mb analysis noon Sunday Nov. 12 2017




                                      500mb Forecast noon Tuesday November 14 2017


                                        500 mb Forecast noon Thursday November 16 2017

Precipitation for the coming  week will be most significant with system number two which will affect Western Wyoming/Star Valley Thursday into Friday.  The forecast precipitation for the week ending later Friday indicates up to 2 inches in the Western  Wyoming mountains in the form of snow.  Far less than the up to 15 inches expected in Western Washington.

Total precipitation forecast  for 5 days ending Friday evening Nov. 17 2017

The snowfall for the coming week will be greatest with the second and colder system on Thursday with potentially 1-2 feet in the western Wyoming mountains.


                    Total Model Snowfall for the 5 day period ending Friday Evening Nov. 17 2017