Thunderstorms produced strong wind gusts near Cheyenne and north of Lance Creek.
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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.
Thunderstorms produced strong wind gusts near Cheyenne and north of Lance Creek.
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 Aug 14, 1:58 PM MST, 47 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 258 PM MDT Mon Aug 14 2017 .SHORT TERM...(This Evening through Wednesday) Issued at 300 PM MDT Mon Aug 14 2017 Scattered showers and thunderstorms have developed in the past few hours across southeast WY. Current thinking is the main threat from these storms will be gusty downdrafts with deep boundary layers and large DCAPE values in place. Also cannot rule out small hail as the SPC mesoanalysis shows SBCAPE of 500-750 J/kg and decent bulk shear of 30-40 kts across northern zones. Chance of showers and isolated thunder will continue into the early night. Shortwave trough currently across the Great Basin will move eastward into central WY by Tuesday. Temps will be around 5-10 degrees cooler for tomorrow behind a weak fropa overnight. Expect another round of aftn/evening storms to develop, with the coverage highest for areas to the east of the Laramie Range. There will be a better chance of strong storms mainly over the Nebraska Panhandle during the aftn with CAPE of 1000-1250 J/kg and good deep layer shear. Shortwave trough axis will move into northeast Colorado by late Tuesday night into Wednesday morning. Wednesday will be coolest day with a more stable airmass in place and only isolated storms possible along the Laramie Range. .LONG TERM...(Wednesday night through Monday) Issued at 300 PM MDT Mon Aug 14 2017 Somewhat active northwest flow on Thursday will gradually become westerly by week's end and southwesterly for the weekend and into early next week. The latest GFS and to a lesser extent the ECMWF show shortwave energy diving southeast towards the Dakotas on Thursday. The associated sfc frontal boundary to be the focus for at least weak afternoon/evening convection. Progd SBCAPE's are at most 500 j/kg across our eastern portion of the Panhandle, so would not expect much organization to the convection. Dry, stable air mass will yield a dry day on Friday. Flow turns more southwest as the weekend wears on, which should advect moisture back northeast into the CWA. Have added afternoon precip chances to the Snowy/Sierra Madres on Saturday/Sunday as a result. This pattern would be conducive to afternoon/evening shower/thunderstorm chances lingering on Monday afternoon as well. For now, have confined these to areas in east-central Wyoming after 18z. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1225 PM MDT Mon Aug 14 2017 Main concerns for aviation ops will be the timing and location of afternoon and nighttime convection that will develop and move across the region. Latest info suggests thunderstorms will continue developing near KCYS/KLAR after 19z. KRWL will likely see some convective development as well, though the drier air mass will likely only yield high-based showers capable of producing gusty outflow winds. This area of -TSRA/-SHRA will lift northeast towards western Nebraska Panhandle sites 21-23Z. The bulk of the activity will likely depart by around 05Z, with perhaps a second round of showers and/or weak thunderstorms lingering overnight. For now have kept VCTS confined to the location and timing above. May need to linger convection a bit longer on the 00z/06z TAF cycles. && .FIRE WEATHER... Issued at 200 PM MDT Mon Aug 14 2017 Minimal fire weather concerns through midweek. We expect good chances for showers and thunderstorms this afternoon through Tuesday. Some of the storms will produce wetting rains. Afternoon humidities could drop down to 15-20 percent across portions of southeast Wyoming by this weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...ZF LONG TERM...CAH AVIATION...CAH FIRE WEATHER...ZF
Hazardous Weather Outlook National Weather Service Cheyenne WY 344 AM MDT Mon Aug 14 2017 NEZ054-055-WYZ103>106-109>119-151030- Kimball-Cheyenne-North Laramie Range- Ferris/Seminoe/Shirley Mountains-Shirley Basin- Central Laramie Range and Southwest Platte County- Central Carbon County-North Snowy Range Foothills- 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- 344 AM MDT Mon Aug 14 2017 This hazardous weather outlook is for portions of western Nebraska...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Widely scattered thunderstorms are expected over the area this afternoon and evening. Severe storms are not anticipated. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY Widely scattered afternoon and evening thunderstorms are possible mainly on Tuesday and Thursday. .Spotter information statement... Spotter activation will not be needed. NEZ002-003-019>021-095-096-WYZ101-102-107-108-151030- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-North Sioux- South Sioux-Converse County Lower Elevations-Niobrara County- East Platte County-Goshen County- 344 AM MDT Mon Aug 14 2017 This hazardous weather outlook is for portions of western Nebraska...east central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Scattered showers and thunderstorms are expected over the area this afternoon and evening. A few storms could become strong to severe with hail the main threat. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY Widely scattered afternoon and evening thunderstorms are possible mainly on Tuesday and Thursday. .Spotter information statement... Spotter activation is not anticipated at this time.
Special Weather Statement National Weather Service Cheyenne WY 329 PM MDT MON AUG 14 2017 WYZ117-118-142200- Central Laramie County WY-South Laramie Range Foothills WY- 329 PM MDT MON AUG 14 2017 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL LARAMIE COUNTY UNTIL 400 PM MDT... At 329 PM MDT, Doppler radar was tracking a strong thunderstorm over Cheyenne, moving northeast at 15 mph. Wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Cheyenne, South Greeley, Ranchettes, Warren AFB, Frontier Park, North Cheyenne, Warren Af Base, Fox Farm-College and South Greeley High. This includes the following highways... Interstate 25 in Wyoming between mile markers 6 and 21. Interstate 80 in Wyoming between mile markers 355 and 373. LAT...LON 4102 10474 4111 10494 4144 10477 4131 10445 TIME...MOT...LOC 2129Z 208DEG 15KT 4113 10480 Levin
The Cheyenne radar (KCYS), 1 km away, was scanning. The volume nearest the first event began at 21:46 UTC.
2 thunderstorm wind. Local standard time, as filed.
Estimated wind gusts of 55 to 60 mph were observed just east of Cheyenne.
Estimated wind gusts of 55 to 60 mph were observed north of Lance Creek.
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, August 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: 712267, 712269.