Strong gap winds with gusts of 60 to 70 mph developed across the Interstate 25 and 80 wind corridors in southeast Wyoming.
Every event with a place to put it; 18 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
Strong gap winds with gusts of 60 to 70 mph developed across the Interstate 25 and 80 wind corridors in southeast Wyoming.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Dec 17, 10:25 AM MST, 2 hours 50 minutes earlier.
Area Forecast Discussion...CORRECTED National Weather Service Cheyenne WY 1025 AM MST Sun Dec 17 2017 .UPDATE... Issued at 1018 AM MST Sun Dec 17 2017 Light mixed wintry precipitation and areas of freezing fog observed earlier this morning have dissipated. Areas of low stratus affecting Alliance, Douglas, Scottsbluff, Sidney and Torrington persist late this morning. Latest model trends show these low cloud ceilings lifting through early afternoon. Updated grids and zones to account for these trends. && .SHORT TERM...(Today through Monday) Issued at 305 AM MST Sun Dec 17 2017 Deep low-level saturation and moist upslope flow is supporting fog and patchy freezing drizzle, along with areas of light snow along/ east of the Laramie Range this AM. Radar & GOES-16 IR imagery have been indicative of a decrease in overall precipitation coverage w/ precipitation ending in northern areas. WYDOT web cams show little or no snow cover on roads in Converse county, so we have cancelled the inherited Winter Weather Advisory. Areas of dense fog continue along I-80 between Laramie & Cheyenne. We opted to remove the city of Cheyenne from the Dense Fog Advisory as local visibilities have improved and will likely not fall again with precipitation falling at this time. We will re-evaluate the I-80 summit prior to the 13z expiration. Generally minimal impacts from this, but will continue to strongly message potential for areas of icy road conditions and low visibility this AM. Conditions improving through the day w/sfc flow becoming westerly in response to a passing trough axis. Some concern for high winds in the wind corridors late tonight and early Monday. A strong short-wave will track across Saskatchewan & Manitoba during this time, enhancing low-lvl height gradients over southeast Wyoming. NAM/GFS CAG-CPR gradients climb to 50-60 meters at both H7/H85, but a lack of stronger flow aloft could limit risk for warning-criteria gusts. The GFS peaks H7 flow around 35 kts at ARL, and H8 flow near 50 kts at BRX early Monday. Am not confident enough to issue any high wind headlines at this time, but the best chance for 50+ kt gusts appears to be at BRX between 12-18z Mon. .LONG TERM...(Monday Night through Saturday) Issued at 305 AM MST Sun Dec 17 2017 Dry and somewhat mild conditions expected Tuesday and Wednesday before big changes sweep in Thursday through the next weekend when more typical Wyoming and western Nebraska winter conditions return home for a holiday visit. Models in fair agreement bringing a significant chance of snow to the area Wednesday night into Thursday morning behind a strong Arctic cold front that will move through late Wednesday. Model blends continue to be catching up with trends towards higher snow amounts Thursday, so we went a little above the blends on snow totals during the day on Thursday when colder air becomes more deeply entrenched along the deep moisture and lift axis as the upper trough moves across. ECMWF and to some degree the GFS bring a closed low across Colorado Thursday, which is a little stronger than the previous 00Z runs. The low level pressure gradient Thursday would suggest northerly winds 15 to 25 mph with strong cold advection and potential for some blowing and drifting snow. So, there is the real potential for travel impacts across the region on Thursday, and folks need to stay tuned in on that. Also, in addition to the snow potential, wind chills and cold temperatures will be the main message for the latter part of the week. && .AVIATION...(For the 18Z TAFS through 18Z Monday morning) Issued at 1017 AM MST Sun Dec 17 2017 Patchy MVFR/IFR cigs affecting mainly the Neb Panhandle will break up by 20Z with VFR conditions then expected areawide through tonight. Some gusty winds possible around the mtns later tonight as well. && .FIRE WEATHER... Issued at 245 AM MST Sun Dec 17 2017 Cooler temperatures and abundant low-level moisture will limit the potential for critical fire weather conditions. Minimum RHs should remain well outside of critical thresholds through the week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && UPDATE...MAJ SHORT TERM...CLH LONG TERM...JG AVIATION...RE FIRE WEATHER...CLH
Hazardous Weather Outlook...CORRECTED National Weather Service Cheyenne WY 1035 AM MST Sun Dec 17 2017 WYZ101>105-107>109-111>119-181700- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-East Platte County-Goshen County- Central Carbon County-Southwest Carbon County-Sierra Madre Range- Upper North Platte River Basin-Snowy Range-Laramie Valley- South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 1035 AM MST Sun Dec 17 2017 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A strong cold front will sweep across the region Wednesday night and Thursday. This front will be accompanied by widespread accumulating snowfall and much colder temperatures, with morning lows in the single digits below zero possible Friday. Those with early holiday travel plans from mid to late this week should continue to monitor the latest weather forecasts as details on this storm become more clear. .Spotter information statement... Spotter activation will not be required. WYZ106-110-181700- Central Laramie Range and Southwest Platte County- North Snowy Range Foothills- 1035 AM MST Sun Dec 17 2017 This hazardous weather outlook is for portions of south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Strong west winds with gusts of 50 to 60 mph may develop late tonight, impacting travel for lightweight and high profile vehicles along Interstate 25 between Chugwater and Wheatland, and Interstate 80 through Arlington and Elk Mountain. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Strong west winds with gusts of 50 to 60 mph may continue through late Monday afternoon. A strong cold front will sweep across the region Wednesday night and Thursday. This front will be accompanied by widespread accumulating snowfall and much colder temperatures, with morning lows in the single digits below zero possible Friday. Those with early holiday travel plans from mid to late this week should continue to monitor the latest weather forecasts as details on this storm become more clear. .Spotter information statement... Spotter activation will not be required. NEZ002-003-019>021-054-055-095-096-181700- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 1035 AM MST Sun Dec 17 2017 This hazardous weather outlook is for portions of western Nebraska. .DAY ONE...TODAY AND TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A strong cold front will sweep across the region Wednesday night and Thursday. This front will be accompanied by widespread accumulating snowfall and much colder temperatures, with morning lows in the single digits above zero Friday. Those with early holiday travel plans from mid to late this week should continue to monitor the latest weather forecasts as details on this storm become more clear. .Spotter information statement... Spotter activation will not be required.
Special Weather Statement National Weather Service Cheyenne WY 800 AM MST Sun Dec 17 2017 WYZ115-171630- Laramie Valley- Including the cities of Bosler and Laramie 800 AM MST Sun Dec 17 2017 ...AREAS OF FOG AFFECTING LARAMIE AND THE LARAMIE VALLEY THROUGH MID MORNING... Motorists traveling through the Laramie Valley, including Laramie, will encounter areas of dense fog through mid morning. Visibilities will be reduced to a quarter mile at times. In addition, freezing fog will cause slick spots on area roadways, including Interstate 80. Reduce speeds, use low beam headlights and increase following distances between vehicles.
Special Weather Statement National Weather Service Cheyenne WY 100 PM MST Sun Dec 17 2017 WYZ110-172300- North Snowy Range Foothills- Including the cities of Arlington and Elk Mountain 100 PM MST Sun Dec 17 2017 Sustained west winds of 30 to 40 mph with gusts to around 55 mph will occur along Interstate 80 between mile markers 240 and 285 this afternoon. This includes Arlington and Elk Mountain. Those traveling with lightweight and high profile vehicles should exercise caution and be alert for sudden wind gusts.
The national radar mosaic for the moment the first event began.
18 high wind. Local standard time, as filed.
The WYDOT sensor at Halleck Ridge measured sustained winds of 40 mph or higher.
The WYDOT sensor at Arlington measured sustained winds of 40 mph or higher, with a peak gust of 68 mph at 17/1500 MST.
The WYDOT sensor at Foote Creek measured sustained winds of 40 mph or higher.
The UPR sensor at Buford measured peak wind gusts of 64 mph.
The WYDOT sensor at Wildcat Trail measured sustained winds of 40 mph or higher, with a peak gust of 660 mph at 18/0710 MST.
The WYDOT sensor at Arlington measured wind gusts of 58 mph or higher, with a peak gust of 69 mph at 18/0830 MST.
The WYDOT sensor at Foote Creek measured sustained winds of 40 mph or higher, with a peak gust of 59 mph at 18/0900 MST.
The WYDOT sensor at Arlington East measured sustained winds of 40 mph or higher, with a peak gust of 58 mph at 18/0855 MST.
The WYDOT sensor at Cooper Cove measured sustained winds of 40 mph or higher, with a peak gust of 65 mph at 18/0850 MST.
The WYDOT sensor at Remount Road measured sustained winds of 40 mph or higher.
The WYDOT sensor at Otto Road measured wind gusts of 58 mph or higher, with a peak gust of 67 mph at 18/1040 MST.
The UPR sensor at Emkay measured wind gusts of 58 mph or higher, with a peak gust of 76 mph at 18/1055 MST.
The UPR sensor at Lynch measured wind gusts of 58 mph or higher, with a peak gust of 61 mph at 18/1055 MST.
A peak wind gust of 64 mph was measured at Wheatland.
The WYDOT sensor at Whitaker measured sustained winds of 40 mph or higher.
The WYDOT sensor at Interstate 80 mile post 353 measured sustained winds of 40 mph or higher, with a peak gust of 65 mph at 18/1230 MST.
The WYDOT sensor at Halleck Ridge measured sustained winds of 40 mph or higher, with a peak gust of 62 mph at 18/1210 MST.
The WYDOT sensor at Bordeaux measured peak wind gusts of 58 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, 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: 730733, 730727, 730730, 730735, 730738, 730728, 730731, 730726, 730729, 730737, 730742, 730739, 730736, 730725, 730743, 730740, 730734, 730724.