Alert archive / Wyoming / Winter Storm Warnings in 2024

Winter Storm Warning 21, NWS Riverton, WY

December 15, 20244 counties in Wyoming

NWS Riverton, WY issued this winter storm warning at Dec 15, 2024, 11:46 PM MST for 4 counties in Wyoming. It took effect at Dec 16, 2024, 11:00 AM MST. It was in force for 30 hr. 60 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Dec 15, 2024, 11:46 PM MST (06:46 UTC)
In effect from
Dec 16, 2024, 11:00 AM MST
Expired
Dec 17, 2024, 5:00 PM MST
In force
30 hr
Issued by
NWS Riverton, WY

Counties Fremont County, WY, Lincoln County, WY, Sublette County, WY, Teton County, WY

The radar

The Riverton/Lander radar (KRIW), 120 km from the middle of the area, began a volume at 06:45 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Dec 16, 3:00 PM MSTSNOW 111 N Dubois, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 13 W Boulder, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1.811 Ne Marbleton, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 212 Nnw Shoshoni, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 316 E Moran Junction, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 31 Nne Pinedale, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 323 Nw Dubois, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 3.819 Ne Bondurant, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 3.85 Se Pinedale, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 41 Nnw Pinedale, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 4Kelly, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 516 Sw Dubois, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 522 E South Entrance, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 523 Ese Moran Junction, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 55 Nw Daniel, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 5.84 Ne Thayne, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 5.86 Wnw Cora, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 615 Ene Cokeville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 617 Wnw South Pass City, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 62 Nnw Turnerville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 62 Nw Teton Village, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 62 Ssw Grant Village, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 6South Entrance, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 6.24 Nne Thayne, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 6.2Afton, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 6.42 S Bedford, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 6.51 Se Thayne, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 711 Nne Pinedale, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 712 Ese Bondurant, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 719 Ne Bondurant, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 7Jackson, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 7.51 Nne Pinedale, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 811 E Big Sandy, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 815 Nne Cokeville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 81 Nne Jackson, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 81 S Jackson, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 820 Nw Calpet, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 83 N Etna, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 88 Nne Moran Junction, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 921 Ne Cokeville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 92 Nne Teton Village, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 95 Ene Alta, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 96 Nnw Moose, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1010 Ene Turnerville, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1012 N Cora, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 1014 E Bondurant, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 1015 Ese Smoot, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 1016 Ene Turnerville, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1020 E Bondurant, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 105 N South Entrance, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 106 Ene Smoot, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 108 S Smoot, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 113 Se Turnerville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 115 Sse Smoot, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 116 E Alta, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1210 Ese Smoot, WYStorm Total Snowfall.
Dec 16, 3:00 PM MSTSNOW 1210 N Bondurant, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 1216 Ene Turnerville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 1217 Ese Turnerville, WYStorm total snowfall.
Dec 16, 3:00 PM MSTSNOW 123 Ssw Wilson, WYStorm Total Snowfall.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 6.8 hours before the alert went out and 126 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Riverton, WY at 00:00Z on 2024-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 00:00Z on 2024-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2585 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

671 
WWUS45 KRIW 160646
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
1146 PM MST Sun Dec 15 2024

WYZ012-170015-
/O.NEW.KRIW.WS.W.0021.241216T1800Z-241218T0000Z/
Teton and Gros Ventre Mountains-
1146 PM MST Sun Dec 15 2024

...WINTER STORM WARNING IN EFFECT FROM 11 AM MONDAY TO 5 PM MST 
TUESDAY...

* WHAT...Heavy snow expected. Total snow accumulations up to 2 feet 
  for the Tetons and up to a foot for the Gros Ventres.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...From 11 AM Monday to 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Monday evening and Tuesday 
  morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ001-170015-
/O.NEW.KRIW.WW.Y.0039.241216T1800Z-241218T0000Z/
Yellowstone National Park-
Including the cities of Old Faithful, Lake, and Mammoth
1146 PM MST Sun Dec 15 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM MONDAY TO 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations over a foot for 
  southwestern portions of the park with less than 6 inches possible 
  from Mammoth Springs to Tower Junction.

* WHERE...Yellowstone National Park.

* WHEN...From 11 AM Monday to 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Monday evening and Tuesday 
  morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ013-170015-
/O.NEW.KRIW.WW.Y.0039.241216T1800Z-241218T0000Z/
Jackson Hole-
Including the cities of Jackson
1146 PM MST Sun Dec 15 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM MONDAY TO 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations between 4 and 8 
  inches.

* WHERE...Jackson Hole.

* WHEN...From 11 AM Monday to 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ024-170015-
/O.NEW.KRIW.WW.Y.0039.241216T2000Z-241218T0000Z/
Salt River and Wyoming Ranges-
1146 PM MST Sun Dec 15 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 1 PM MONDAY TO 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations up to a foot. Winds 
  gusting as high as 35 mph.

* WHERE...Salt River and Wyoming Ranges.

* WHEN...From 1 PM Monday to 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Monday evening and Tuesday 
  morning commutes, including Salt River Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ014-170015-
/O.NEW.KRIW.WW.Y.0039.241216T2200Z-241218T0000Z/
Wind River Mountains West-
1146 PM MST Sun Dec 15 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM MONDAY TO 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations up to a foot. Winds 
  gusting as high as 35 mph.

* WHERE...Wind River Mountains West.

* WHEN...From 3 PM Monday to 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes, 
  including South Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Lowe
5 follow-up statements
762 
WWUS45 KRIW 161923
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
1223 PM MST Mon Dec 16 2024

WYZ024-171300-
/O.UPG.KRIW.WW.Y.0039.241216T2000Z-241218T0000Z/
/O.EXB.KRIW.WS.W.0021.241216T2000Z-241218T0000Z/
Salt River and Wyoming Ranges-
1223 PM MST Mon Dec 16 2024

...WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Total snow accumulations between 10 
  and 16 inches. Winds gusting as high as 40 mph.

* WHERE...Salt River and Wyoming Ranges.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes, 
  including Salt River Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ014-171300-
/O.UPG.KRIW.WW.Y.0039.241216T2200Z-241218T0000Z/
/O.EXB.KRIW.WS.W.0021.241216T2200Z-241218T0000Z/
Wind River Mountains West-
1223 PM MST Mon Dec 16 2024

...WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Total snow accumulations between 10 
  and 16 inches. Winds gusting as high as 40 mph.

* WHERE...Wind River Mountains West.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes, 
  including South Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ012-171300-
/O.CON.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Teton and Gros Ventre Mountains-
1223 PM MST Mon Dec 16 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Total snow accumulations up to 2 feet 
  for the Tetons and 10 to 18 inches for the Gros Ventres.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ023-171300-
/O.EXB.KRIW.WW.Y.0039.241216T2000Z-241218T0000Z/
Star Valley-
Including the cities of Star Valley Ranch, Afton, Thayne, and
Alpine
1223 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Snow expected. Total snow accumulations between 4 and 8 
  inches.

* WHERE...Star Valley.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ001-171300-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Yellowstone National Park-
Including the cities of Mammoth, Lake, and Old Faithful
1223 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations over a foot for 
  southwestern portions of the park with 2 to 6 inches near Old 
  Faithful, and up to 1 to 3 inches from Mammoth to Tower Junction..

* WHERE...Yellowstone National Park.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ013-171300-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Jackson Hole-
Including the cities of Jackson
1223 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Total snow accumulations between 4 and 8 
  inches.

* WHERE...Jackson Hole.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Monday evening and Tuesday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Dziewaltowski
950 
WWUS45 KRIW 170655
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
1155 PM MST Mon Dec 16 2024

WYZ012-180000-
/O.CON.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Teton and Gros Ventre Mountains-
1155 PM MST Mon Dec 16 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Additional snow accumulations up to a 
  foot for the Tetons and 6 to 10 inches for the Gros Ventres.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Tuesday morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ014-180000-
/O.CON.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Wind River Mountains West-
1155 PM MST Mon Dec 16 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Additional snow accumulations between 
  6 and 10 inches. Winds gusting as high as 30 to 40 mph.

* WHERE...Wind River Mountains West.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Tuesday morning commute, including South Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ024-180000-
/O.CON.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Salt River and Wyoming Ranges-
1155 PM MST Mon Dec 16 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST TUESDAY...

* WHAT...Heavy snow expected. Additional snow accumulations between 
  6 and 10 inches. Winds gusting as high as 30 to 40 mph.

* WHERE...Salt River and Wyoming Ranges.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Tuesday morning commute, including Salt River 
  Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ001-180000-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Yellowstone National Park-
Including the cities of Old Faithful, Lake, and Mammoth
1155 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Additional snow accumulations up to 6 inches 
  for southwestern portions of the park with 2 to 4 inches near Old 
  Faithful, and up to 2 inches from Mammoth to Tower Junction.

* WHERE...Yellowstone National Park.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Tuesday morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ013-180000-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Jackson Hole-
Including the cities of Jackson
1155 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST 
TUESDAY...

* WHAT...Snow. Additional snow accumulations between 2 and 4 inches.

* WHERE...Jackson Hole.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Tuesday morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ023-180000-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Star Valley-
Including the cities of Star Valley Ranch, Afton, Thayne, and
Alpine
1155 PM MST Mon Dec 16 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST 
TUESDAY...

* WHAT...Snow expected. Additional snow accumulations up to 2 inches.

* WHERE...Star Valley.

* WHEN...Until 5 PM MST Tuesday.

* IMPACTS...Plan on slippery road conditions. The hazardous 
  conditions could impact the Tuesday morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Lowe
725 
WWUS45 KRIW 172017
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
117 PM MST Tue Dec 17 2024

WYZ012-014-172130-
/O.CAN.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Teton and Gros Ventre Mountains-Wind River Mountains West-
117 PM MST Tue Dec 17 2024

...WINTER STORM WARNING IS CANCELLED...

The bulk of snowfall has come to an end. Light snow showers will 
linger through the evening into the morning hours on Wednesday. High 
elevations may see an additional 1 to 2 inches of snow accumulation 
by Wednesday morning.

$$

WYZ001-013-172130-
/O.CAN.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Yellowstone National Park-Jackson Hole-
Including the cities of Lake, Old Faithful, Mammoth, and Jackson
117 PM MST Tue Dec 17 2024

...WINTER WEATHER ADVISORY IS CANCELLED...

The bulk of snowfall has come to an end. Light snow showers will 
linger through the evening into the morning hours on Wednesday. Most 
will see Little to no additional accumulation.

$$

WYZ024-180000-
/O.CON.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Salt River and Wyoming Ranges-
117 PM MST Tue Dec 17 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS 
AFTERNOON...

* WHAT...Heavy snow. Additional snow accumulations up to two inches.

* WHERE...Salt River and Wyoming Ranges.

* WHEN...Until 5 PM MST this afternoon.

* IMPACTS...Plan on slippery road conditions. The hazardous 
  conditions could impact the Tuesday evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency.

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

WYZ023-180000-
/O.CON.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Star Valley-
Including the cities of Alpine, Afton, Thayne, and Star Valley
Ranch
117 PM MST Tue Dec 17 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS 
AFTERNOON...

* WHAT...Snow. Additional snow accumulations up to one inch.

* WHERE...Star Valley.

* WHEN...Until 5 PM MST this afternoon.

* IMPACTS...Plan on slippery road conditions. The hazardous 
  conditions could impact the Tuesday evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

For graphical depictions of the snowfall forecast, including the 
official NWS forecast, high end amounts, and low end amounts, visit 
https://weather.gov/riw/winter .

For winter road conditions from the Wyoming Department of 
Transportation, visit https://wyoroad.info .

&&

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Dziewaltowski
794 
WWUS45 KRIW 180015
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
515 PM MST Tue Dec 17 2024

WYZ024-180115-
/O.EXP.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Salt River and Wyoming Ranges-
515 PM MST Tue Dec 17 2024

...WINTER STORM WARNING HAS EXPIRED...

Snow has generally ended across the area. Therefore, the Winter 
Storm Warning has expired.

$$

WYZ023-180115-
/O.EXP.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Star Valley-
Including the cities of Afton, Star Valley Ranch, Alpine, and
Thayne
515 PM MST Tue Dec 17 2024

...WINTER WEATHER ADVISORY HAS EXPIRED...

Snow has generally ended across the area. Therefore, the Winter 
Storm Warning has expired.

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Myers
568 
WWUS45 KRIW 180029 CCA
WSWRIW

URGENT - WINTER WEATHER MESSAGE...CORRECTED
National Weather Service Riverton WY
529 PM MST Tue Dec 17 2024

WYZ024-180130-
/O.EXP.KRIW.WS.W.0021.000000T0000Z-241218T0000Z/
Salt River and Wyoming Ranges-
529 PM MST Tue Dec 17 2024

...WINTER STORM WARNING HAS EXPIRED...

Snow has generally ended across the area. Therefore, the Winter 
Storm Warning has expired.

$$

WYZ023-180130-
/O.COR.KRIW.WW.Y.0039.000000T0000Z-241218T0000Z/
Star Valley-
Including the cities of Afton, Star Valley Ranch, Alpine, and
Thayne
529 PM MST Tue Dec 17 2024

...WINTER WEATHER ADVISORY HAS EXPIRED...

Snow has generally ended across the area. Therefore, the Winter 
Weather Advisory has expired.

$$

For more information from the National Weather Service, visit 
https://weather.gov/riw/ .

Myers

What forecasters said that day

The local office's own words before this winter storm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Riverton, WY wrote its last area forecast discussion before this winter storm warning went out at Dec 15, 9:48 PM MST, 1 hour 58 minutes earlier. Its key messages:

  • Snow and wind continues today, with lessening impacts through the afternoon and evening.
  • Another system Monday and Tuesday brings gusty winds or the Wind Corridor and western Wyoming snow.
  • Warm and dry the second half the week.
Area forecast discussion, Dec 15, 9:48 PM MST, 1 hour 58 minutes before
Area Forecast Discussion
National Weather Service Riverton WY
948 PM MST Sun Dec 15 2024

.KEY MESSAGES...

- Snow and wind continues today, with lessening impacts through
  the afternoon and evening.

- Another system Monday and Tuesday brings gusty winds or the
  Wind Corridor and western Wyoming snow.

- Warm and dry the second half the week.

&&

.DISCUSSION...
Issued at 1055 AM MST Sun Dec 15 2024

Coming in this morning, snow amounts looked to be on track as of
about 5am, with largely 8 to 12 inches over the western mountains.
However, snow rates fell a bit more than expected over the western
mountains during the morning, limiting some accumulations. As a
result, western mountain totals may be slightly less than
forecasted. Models did do a good job indicating a push of heavier
snow mid-morning though, which should bring much of the remaining
snow amounts for this storm. Snow rates will slowly decrease this
afternoon, ending this evening. Snow over the Bighorn Mountains end
by about midnight.

For lower elevations outside the western valleys, little to nothing
expected today. A possible shower may bring a few moments of snow,
but a majority of people see nothing. The Casper area, as well as
Johnson County, may be the exception as a cold front moves through
this evening. Some snow (or rain/snow mix given temperatures) is
possible between about 4pm and midnight. With temperatures
relatively quickly dropping from the 40s to 20s in that timeframe,
there could be some icy conditions, especially on overpasses and
bridges, if precipitation does fall.

The other weather element today is wind. Synoptic driven winds will
continue through the afternoon and early evening, with widespread
gusts 20 to 30 mph. Stronger winds are across the Wind Corridor. As
the front passes this evening, a strong north wind moves through
Johnson County. Given this favored flow, Buffalo is expected to see
30 to 40 mph winds. With the initial pass, gusts around 45 mph
are expected. There is about a 20 percent chance for winds 50 to
55 mph. Gusty winds remain for the Wind Corridor and the
mountains overnight and through the day Monday.

A quick turn around after today's storm moves out and another
system impacts the area Monday and Tuesday. Main impacts are
once again to the western mountains, where an additional 8 to 12
inches are possible for the Tetons. The northern Salt/Wyoming
Ranges and the Gros Ventres are more in the 6 to 10 range. Given
current winter highlights, will not be issuing any products
with this forecast package and will allow night shift to
reevaluate snow amounts.

The last flakes should fall Tuesday night, leaving a dry Wednesday
across the area (outside maybe a few lingering light snow showers
over the Tetons through Wednesday morning). Ridging will keep above
normal temperatures and dry conditions across the area through the
second half of the week, a similar pattern to what much of this
season has seen so far. Conditions look warm and dry through
December 22nd. Long range guidance is hinting at a system the 23rd,
but very low confidence this far out.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 945 PM MST Sun Dec 15 2024

West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals.

VFR conditions in place to start the TAF period. There is some
indication for fog at KBPI, but confidence is not high on this
and will just include a low scattered deck for now. The next
system will follow quickly, moving into western Wyoming after
12Z. MVFR conditions are likely at KJAC before 18Z as snow
redevelops. IFR/MVFR conditions become likely by 21Z. While
ceilings will lower at KBPI and KPNA during the afternoon, snow
impacts are largely expected to hold off until after 00Z
Tuesday. IFR/MVFR conditions are then expected at these
terminals by 03Z.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals.

Gusty winds around 25 kt will continue at KCPR to begin the
forecast. These winds will decrease by 09Z, before increasing
again by 18Z. KCOD will also continue to have gusts around 20 kt
through 12Z. VFR conditions are expected through the period.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing, and turbulence forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...Wittmann
AVIATION...LaVoie/Myers
Hazardous weather outlook, Dec 15, 1:10 AM MST, 22 hours 36 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
110 AM MST Sun Dec 15 2024

WYZ001>020-022>030-161215-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Bighorn Basin-Southwest Bighorn Basin-Southeast Bighorn Basin-
Owl Creek and Bridger Mountains-Bighorn Mountains West-
Bighorn Mountains Southeast-Northeast Johnson County-
Southeast Johnson County-Teton and Gros Ventre Mountains-
Jackson Hole-Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
110 AM MST Sun Dec 15 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...
...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...
...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...
...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...
...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...
...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON...

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight.

Light to moderate snow continues through much of the day tapering off
west to east through the afternoon and evening hours. Gusty winds
continue as well, highest for Natrona County.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

The next storm system will bring another round of wind and snow for
Monday night into Tuesday.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 11:46 PM MSTWinter Weather AdvisoryRIWFremont, Lincoln, Park, Sublette, Teton41 hr

Nearby

Winter Storm Warnings in Wyoming, 2024Every winter storm warning in 2024

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.