A brief period of strong post-frontal west to northwest winds occurred from the central Laramie Range to central Laramie County.
Every event with a place to put it; 9 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.
A brief period of strong post-frontal west to northwest winds occurred from the central Laramie Range to central Laramie County.
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 Sep 19, 2:23 PM MST, 1 hour 37 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 323 PM MDT Tue Sep 19 2017 .SHORT TERM...(This evening through Thursday Night) Issued at 305 PM MDT Tue Sep 19 2017 Cold front moving into the plains currently and will move across the Panhandle by early this evening. Expect area of rain and some light snow to continue out west for the rest of the afternoon then break up this evening as a shortwave lifts north away from the area. Skies gradually clearing later tonight. Dry and mild conditions on tap for Weds with breezy conditions over the plains in the afternoon as decent mid level flow mixes down. mainly clear Weds night and Thursday as the upper flow turns southwesterly and advects some drier air over the region. Warmer Thursday ahead of significant upper trough digging over the western CONUS. .LONG TERM...(Friday through Monday) Issued at 305 PM MDT Tue Sep 19 2017 Models are in rather good agreement at showing a cool and unsettled period from Friday into early next week. Unseasonably deep upper trough will be centered across the Great Basin on Friday. Little movement is forecasted through Saturday, and then the trough will shift eastward slowly into early next week. This will keep the CWA in an area of good upper level divergence and large scale lift from Friday evening into Monday morning, with an extended period of elevated precip chances. Wet bulb zero heights and snow levels will generally remain above 10000 ft through Saturday and then fall by Sunday night to Monday to around 8000 ft as the colder air aloft moves overhead. Current thinking is that lower elevations will be mostly rain through early next week, with the higher terrain of the Sierra Madre and Snowy Ranges potentially seeing more significant accumulations. Highs will struggle to get out of the low 50s by Monday, which is 15-20 degrees below normal for late September. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1154 AM MDT Tue Sep 19 2017 Mostly vfr conditions through the taf period. Rain showers will be possible through the afternoon for sites to the west of Laramie Range (RWL/LAR), with brief MVFR cigs at RWL. A cold front will push across the region through 00Z with winds becoming west to northwest. Gusts to 30-35 kts will be common behind the front through 03Z. && .FIRE WEATHER... Issued at 305 PM MDT Tue Sep 19 2017 Cold front will sweep across the area late this afternoon into early this evening bringing much cooler air and a period of gusty winds behind it. There will be areas of rain and snow over mainly western districts into this evening before ending. It will be a little cooler Wednesday. Some elevated fire weather concerns are expected over the plains Wednesday afternoon as humidities look to fall to about 15 to 20 percent and winds gust close to 25 mph. Warm temperatures will occur Thursday then an approaching low pressure system will bring cooler and wetter conditions by the weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning until 5 PM MDT this afternoon for WYZ309-310. NE...None. && SHORT TERM...RE LONG TERM...ZF AVIATION...ZF FIRE WEATHER...RE
Special Weather Statement
National Weather Service Cheyenne WY
345 PM MDT TUE SEP 19 2017
WYZ109>111-113-114-192315-
Upper North Platte River Basin-North Snowy Range Foothills-Central
Carbon County-Southwest Carbon County-Snowy Range-
345 PM MDT TUE SEP 19 2017
...SNOW SHOWERS REDUCING VISIBILITIES ALONG INTERSTATE 80 FROM
ARLINGTON TO RAWLINS THIS AFTERNOON...
At 340 PM MDT, snow showers were reducing visibilities periodically
along Interstate 80 west of Arlington to just east of Rawlins.
Visibilities at times will be reduced to one quarter to one half of
a mile, making for hazardous driving conditions due to reduced
visibility. These snow showers will continue through late afternoon
before diminishing in the early evening hours. Mostly wet roads are
being anticipated at this time.
Locations impacted include...
Rawlins, Saratoga, Hanna, Sinclair, Elk Mountain, Separation Lake and
Teton Reservoir.
This includes Interstate 80 in Wyoming between mile markers 200 and
270.
LAT...LON 4166 10770 4166 10751 4184 10751 4213 10718
4169 10607 4136 10681 4158 10779
TIME...MOT...LOC 2140Z 240DEG 49KT 4160 10694
GarmonSpecial Weather Statement National Weather Service Cheyenne WY 405 PM MDT Tue Sep 19 2017 NEZ002-003-019>021-054-055-095-096-WYZ102-106>108-116>119-200015- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux-Niobrara County- Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-South Laramie Range- South Laramie Range Foothills-Central Laramie County- East Laramie County- Including the cities of Chadron, Chadron St Park, Alliance, Scottsbluff, Gering, Harrisburg, Angora, Bridgeport, Bayard, Redington, Kimball, Brownson, Sidney, Harrison, Agate, Lusk, Redbird, Bordeaux, Wheatland, Guernsey, Torrington, Buford, Pumpkin Vine, Vedauwoo, Whitaker, Federal, Horse Creek, Cheyenne, and Pine Bluffs 405 PM MDT Tue Sep 19 2017 ...STRONG WIND GUSTS 45 TO 55 MPH BEING OBSERVED BEHIND A STRONG COLD FRONT MOVING SOUTHEAST OUT OF SOUTHEASTERN WYOMING AND ACROSS THE WESTERN NEBRASKA PANHANDLE... At 4 PM MDT, several observation stations across southeast Wyoming and the western Nebraska Panhandle were noting strong wind gusts of 45 to 55 mph blowing from the northwest. These strong crosswinds will affect Interstate 25 from the Colorado border north through the Cheyenne, Chugwater and Wheatland, Wyoming areas. Gust to 45 mph from the northwest will also affect Interstate 80 from Laramie east through Cheyenne, Pine Bluffs, Kimball and eventually the Sidney area. These strong winds from the northwest will continue through early evening. Those driving high profile vehicles or pulling trailers should be alert for sudden strong wind gusts from the northwest which could result in loss of control of the vehicle.
The national radar mosaic for the moment the first event began.
9 high wind. Local standard time, as filed.
The WYDOT sensor at Whitaker measured wind gusts of 58 mph or higher, with a peak gust of 67 mph at 19/2005 MST.
The WYDOT sensor at Bordeaux measured sustained winds of 40 mph or higher, with a peak gust of 62 mph at 16/1635 MST.
The WYDOT sensor at Bear Creek measured wind gusts of 58 mph or higher, with a peak gust of 69 mph at 19/1725 MST.
The wind sensor FE Warren AFB measured sustained winds of 40 mph or higher.
The UPR sensor at Emkay measured sustained winds of 40 mph or higher, with a peak gust of 69 mph at 19/2215 MST.
The WYDOT sensor at Interstate 80 mil post 353 measured sustained winds of 40 mph or higher.
A wind sensor near the Cheyenne Airport measured peak wind gusts of 58 mph.
The UPR sensor at Speer measured sustained winds of 40 mph or higher.
The WYDOT sensor at Wyoming Hill 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, September 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: 718688, 718684, 718690, 718691, 718685, 718686, 718692, 718687, 718689.