A mountain wave broke near Clark and brought a few hour period of very strong winds. There were several gusts over hurricane force including a maximum wind gust of 99 mph.
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The episode as NWS RIW wrote it up.
A mountain wave broke near Clark and brought a few hour period of very strong winds. There were several gusts over hurricane force including a maximum wind gust of 99 mph.
The local office's own words before the first event, 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 the first event at Nov 13, 2:46 PM MST, 5 hours 54 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 246 PM MST Mon Nov 13 2017 .SHORT TERM...This evening through Thursday Issued at 238 PM MST Mon Nov 13 2017 Dry weather will continue this evening with the main concern being winds in the Cody Foothills. The right front quadrant of a 115kt jet max will be pushing in overnight. NAM12 is indicating as high as 55kt winds over the Absaroka Mountains. With some indication of a weak mountain top inversion and downward motion in the area I see no reason not to upgrade the current watch. Winds should decrease as cold advection begins mid Tuesday morning. Tuesday morning will se the return of snow to the western mountains. Models are still below advisory level snowfall so there should not be much impact, 1-3 inches in the higher elevations. This system will be out of the area by Tuesday evening, replaced by a transitional ridge for about 24 hours. Wednesday evening our next system will arrive via a strong pacific low off of the northwest coast. Starting late Wednesday night and slowly increasing through Thursday, snowfall look to be 2 to 5 inches in the valleys and 8 to 12 inches in the western mountains. Winds will also return with this system Thursday, bringing gusts of 50 mph to the Absaroka and Wind Mountains. Gusty winds from the Green Mountains to Casper will also be in the lower 40s. .LONG TERM...(Tuesday night through Monday) Issued at 238 PM MST Mon Nov 13 2017 Overview...A strong Pacific cold front will move across Wyoming Thursday night. Frontal passage Thursday night could bring a period of moderate to locally heavy snow, along with strong gusty wind. Gusty west-northwest wind and rain/snow showers will accompany the front east of the Continental Divide Thursday night-Friday morning with some light snow accumulations possible through midday Friday. A ridge of high pressure will build in over the weekend bringing mainly dry weather with a gradual warming trend through Sunday. Slightly above average temperatures are anticipated Sunday and Monday. The next chance for precipitation could arrive in the west for Monday. Discussion...Medium-range forecast models are in fair agreement with the incoming trough Thursday night and Friday. Overall trend has been to slow this system, with much of the impact coming Thursday night and Friday morning. Some slight timing differences between the GFS and ECMWF regarding cold frontal passage late Thursday and Thursday night. Given the overall trend of this system to slow, have stuck more closely to the ECMWF solution in bringing the front through Thursday night. Best dynamics, moisture, and favored mid- level temperatures for snow production come together in the 00Z/Fri to 18Z/Fri timeframe. Agree with previous forecast that this is looking like winter weather advisory material (6"-12" mtns, 3"-6" western valleys) Thursday night and Friday morning. Light accumulations are likely across the I-80 corridor in Sweetwater County and in the basins east of the Continental Divide. This may end up being more of a central and southern storm with lower precipitation chances across the north. The snow will decrease Friday afternoon and evening from northwest-to-southeast as drier, colder air pushes in from the northwest. H7-5 thermal trough will be across the forecast area Friday afternoon, so clearing could be slow. Bumped post-frontal winds several MPH east of the Continental Divide Friday afternoon, most noticeably in Johnson and Sweetwater counties. Ridging then returns for the weekend with drier and warmer weather in store through Sunday. Winds on Saturday will be gusty out of the west-to-northwest, especially east of the Continental Divide and along the I-80 corridor. GFS and ECMWF differ in the timing of the next trough to swing through sometime around Monday. Main impacts would likely center on light snowfall in the western mountains as this system appears transient. Beyond this, models are showing a strengthening ridge over the western U.S. This pattern looks to persist into the Thanksgiving weekend, with a good chance of above normal temperatures depicted in the CPC 8-14 day outlook. && .AVIATION...For the 00Z TAFS Tuesday through 00Z Wednesday evening Issued at 238 PM MST Mon Nov 13 2017 All terminals except KJAC to be VFR through 00Z/Wed. Shortwave in progressive westerly flow will track across the northern-third of the forecast area late tonight and Tuesday morning. Aided by some left-exit region jet dynamics there could be a brief period of enhanced snowfall at KJAC between about 12Z-17Z/Tue. Have trended toward MVFR during this period as jet and surface cold front will work in concert to generate best chance for MVFR and -SN. Ahead of this shortwave, wind will increase along the east slopes of the Absaroka and Wind River ranges. Strong mid-level flow of 50-70kts will create LLWS in the vicinity of KCOD and KLND. West-to-southwest wind will increase through the morning ahead of the cold front. Shortwave axis and the cold front should be in the central and northern basins by 18Z/Tue. Ridging returns in the wake of this system with improving and drying conditions Tuesday afternoon. Gusty west-northwest wind will prevail through much of the afternoon, favoring prone terminals like KBPI, KPNA, and KRIW, and KRKS. && .FIRE WEATHER... Issued AT 238 PM MST Mon Nov 13 2017 A gusty wind will occur in the lee of the Absarokas and Cody Foothills as well as across the southwestern wind corridor from the Red Desert through Natrona County. Although critical fire conditions are not expected, elevated fire weather is possible this evening. Some light snow will spread into the west late tonight through tomorrow. High wind be possible in the Lee of the Absarokas tonight. Dry weather Wednesday, and more snow and winds with our next system Thursday. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 5 AM MST Tuesday for WYZ002-003. && SHORT TERM...Hulme LONG TERM...Jones AVIATION...Jones FIRE WEATHER...Hulme
Hazardous Weather Outlook National Weather Service Riverton WY 258 PM MST Mon Nov 13 2017 WYZ001>020-022>030-142200- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn 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- 258 PM MST Mon Nov 13 2017 ...HIGH WIND WARNING FOR THE ABSAROKAS AND CODY FOOTHILLS TONIGHT... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Tonight and Tuesday. High winds are probable across the Absarokas and Cody Foothills tonight. .DAYS TWO THROUGH SEVEN...Wednesday through Sunday. Wednesday night through Friday morning...Strong winds may develop ahead of the next cold front Wednesday night and Thursday along the east slopes of the Continental Divide and from South Pass to Casper. Snow will increase in the western mountains Thursday, with rain or a rain and snow mix developing the western valleys. Moderate to locally heavy snow is possible in the west Thursday night into Friday morning, with snow levels lowering to valley floors. Some light snow accumulations are possible east of the Divide and along the Interstate 80 corridor Friday morning. .SPOTTER INFORMATION STATEMENT... Spotters are urged to report snowfall amounts and wind gusts above 45 mph.
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
Several hurricane force wind gusts were reported near Clark, including a maximum gust of 99 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2017Every state in 2017This day in weather historyWarnings in Wyoming, November 2017
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 723841.