Strong mid level winds mixed to the surface in the Lee of the Absarokas and brought high winds in some areas near Clark. At the wind sensor 8 miles S of Clark, there were several wind gusts past 58 mph, including a maximum gust of 71 mph.
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The episode as NWS RIW wrote it up.
Strong mid level winds mixed to the surface in the Lee of the Absarokas and brought high winds in some areas near Clark. At the wind sensor 8 miles S of Clark, there were several wind gusts past 58 mph, including a maximum gust of 71 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 Dec 17, 1:38 PM MST, 4 hours 7 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 138 PM MST Sun Dec 17 2017 .SHORT TERM...(This evening through Wednesday) Issued at 117 PM MST Sun Dec 17 2017 A weak high pressure ridge over Idaho and Montana will move east of the western and central Wyoming with west northwest flow increasing behind the ridge. Strong winds will increase over and near the east slopes of the mountains with a high wind threat in the Cody Foothills tonight and Monday. Other areas will have strong winds and local high winds may develop through the wind corridor between Rock Springs and Casper. Some wind gusts to 65 mph have developed in the Green mountains near Muddy Gap already. Non windy areas with fresh snow cover will be cold with potential Fog over night into Monday morning along the rivers and unfrozen lakes. Pacific moisture will gradually increase in the flow through mid week keeping clouds and areas of mountain snow with rather light accumulations each day. Wind will gradually shift to the southwest Monday night and Tuesday with warming temperatures and increasingly gusty winds through Wednesday. .LONG TERM...(Wednesday night through Sunday) Issued at 117 PM MST Sun Dec 17 2017 It makes sense that we will finally descend into the depths of winter as we head into the first day of winter, which arrives at 9:28 am Thursday. The coldest air mass of the season will move toward the area as a powerful cold front sweeps into the area from the north. As expected, the models have slowed the progress of the front down somewhat. As a result, much of Wednesday evening may end up remaining precipitation free. Snow will spread across the area Wednesday night however. There is decent frontogenic forcing along with some jet support. However, the limiting factor will be, like with many of the other Canadian and Arctic Fronts, will be moisture. So at this time, amounts look to fall in the advisory category rather than warning. There are some other hazards however. First will be the possible high wind across the northern Big Horn Basin and Johnson County associated with the strong cold advection behind the front later Wednesday night and Thursday morning. In addition, the snow will be of the light and powdery variety, aka easy to blow around and reduce visibility. This snow should end by Thursday at sunset, the shortest day of the year. In addition, MUCH colder temperatures will move in with highs possibly occurring at midnight for many areas and the temperatures falling through the day. The next question is how cold will it get Thursday night. We will have the arctic air mass, the long nights and fresh snow cover. The one thing that is questionable though is a clear sky. Below zero low temperatures are certainly possible though for many areas. Another cold front with a reinforcing shot of cold air then moves in for Friday. The GFS tries to bring the system into the northwest later Thursday night but given the bias for rushing systems in, we held off precipitation until Friday. This looks to be another shot of snow, although this system has even less moisture to work with, so it would be a mainly light snow, although maybe more than one would expect with very high snow ratios given the very cold air in place. Light snow will likely continue through Friday night and possibly into Saturday as well. Saturday looks to be even colder with highs possible remaining below zero in many areas. And again, lows Saturday and Sunday night will depend on how much clearing there is. However, brutally cold temperatures at night look likely with some lows below minus 20 looking likely for some areas at this point. Stay tuned. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday) Issued at 117 PM MST Sun Dec 17 2017 Largely VFR conditions are expected through 00Z Tuesday. The one exception would be near KJAC where some lower clouds may keep local MVFR conditions around. We also can't rule out some fog in the some of the basin and valleys but not enough confidence to put in the forecast yet. Upslope flow may bring some mountain showers in vicinity and north of KJAC and could cause isolated mountain obscurations. Strong mountain top winds will likely bring some wind shear in vicinity of KCOD through around 19Z Monday. && .FIRE WEATHER... Issued AT 117 PM MST Sun Dec 17 2017 A weak high pressure ridge over Idaho and Montana will move east of the western and central Wyoming with west northwest flow increasing behind the ridge. Strong winds will increase over and near the east slopes of the mountains with a high wind threat in the Cody Foothills tonight and Monday. Other areas will have strong winds and local high winds may develop through the wind corridor between Rock Springs and Casper. Some wind gusts to 65 mph have developed in the Green mountains near Muddy Gap already. Non windy areas with fresh snow cover will be cold with potential Fog over night into Monday morning along the rivers and unfrozen lakes. Pacific moisture will gradually increase in the flow through mid week keeping clouds and areas of mountain snow with rather light accumulations each day. Wind will gradually shift to the southwest Monday night and Tuesday with warming temperatures and increasingly gusty winds through Wednesday. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 8 PM this evening to 8 AM MST Monday for WYZ003. && SHORT TERM...Baker LONG TERM...Hattings AVIATION...Hattings FIRE WEATHER...Baker
Hazardous Weather Outlook National Weather Service Riverton WY 426 PM MST Sun Dec 17 2017 WYZ001>020-022>030-181100- 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- 426 PM MST Sun Dec 17 2017 ...HIGH WIND WARNING IN EFFECT FROM 8 PM THIS EVENING TO 8 AM MST MONDAY FOR THE CODY FOOTHILLS... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Tonight. West winds of 35 to 50 mph with gusts of 60 to 70 mph are expected along the Cody Foothills tonight through early Monday morning. Please see the High Wind Warning for more information. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Tuesday Night into Wednesday morning...Strong wind possible across the Cody Foothills and southern wind corridor from Jeffrey City to Casper. Wednesday through Thursday morning...Another storm system will spread snow and much colder air southeast across the area. Friday and Saturday...An arctic cold front and storm system will spread snow and bitter cold air across the area. .SPOTTER INFORMATION STATEMENT... Spotters in the Cody Foothills, please report any wind damage or wind gusts of 58 mph or higher. Thank you.
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
A maximum wind gust of 71 mph was reported 8 miles south of Clark.
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, December 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: 727980.