A large pressure gradient produced high gap winds throughout portions of east-central and southeast Wyoming. Frequent gusts of 65 to 75 mph were observed.
Every event with a place to put it; 21 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 large pressure gradient produced high gap winds throughout portions of east-central and southeast Wyoming. Frequent gusts of 65 to 75 mph were observed.
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 Oct 6, 10:43 PM MST, 27 minutes earlier.
Area Forecast Discussion
National Weather Service Cheyenne WY
1143 PM MDT Fri Oct 6 2017
.SHORT TERM...(Tonight - Sunday)
Issued at 309 PM MDT Fri Oct 6 2017
High winds are expected from late tonight through much of Saturday
across the typical wind corridors of southeast WY. A strong upper-
level jet is currently punching across southern British Columbia &
northern Washington, and should continue to spread over much of MT
through 00z Sun. As this occurs, large scale subsidence will begin
to increase this evening and become strong on Saturday as the area
is influenced by the right exit region of a 130 knot H25 jet. Low-
level gradients will increase, with the H85 CAG-CPR gradient above
60 meters by 03z this evening, and near 70 meters by 09z. The most
recent GFS shows the gradient remaining above 60 meters through at
least 21z-00z tomorrow. Winds aloft are not quite as strong as the
values we were seeing yesterday, but are still progged to be 40-50
knots in the H7-H8 layer over the wind corridors along w/ a few 50
knot barbs at 0.5 km. In-house probabilistic guidance for Bordeaux
also continues to flag high wind potential, so all High Wind Watch
products have been upgraded to Warnings starting at 3z, continuing
through 00z Sunday. Still concerned about Cheyenne with some model
soundings showing shallow mixing early in the AM w/ 52 knots avail
just off the surface, and both the GFS and NAM showing stronger H7
omega spreading into the I25 corridor. This one will likely depend
almost entirely on lapse rates, so we decided to issue a High Wind
Watch for the city of Cheyenne. Model winds over Laramie are some-
what weaker, but Laramie may get fairly close as well.
Fire weather is a concern Saturday as well for areas along/east of
the Laramie Range, especially into the I-25 corridor from Douglas-
Colorado State Line. Strong downsloping, along w/strong subsidence
should drive dew points much lower than MOS suggests, and actually
most of the consensus temperature guidance has trended warmer from
24 hours ago. We are still looking at RH falling to 10 percent for
parts of FWZ 301/309/310 along w/ strong winds. This required Fire
Weather Watch issuance with this forecast package.
On Sunday, a significant upper-level trough will dig southeastward
into the Great Basin, w/increasingly difluent/moist southwest flow
becoming established over the CWA. A strong cold front will arrive
over northern areas by 18z and should be roughly along a KRWL-KCDR
line by the end of the forecast period at 0z Monday. Precipitation
will initially develop over northern areas during the early to mid
afternoon hours on Sunday, and spread southeast. Snow may mix with
rain as well, along with some light accumulations after 18z Sun.
.LONG TERM...(Sunday Night - Friday)
Issued at 309 PM MDT Fri Oct 6 2017
Main focus this period will be with the post-fropa snow expected
across parts of the CWA Sunday night into Monday. Models in pretty
good agreement though the GFS is a bit of an outlier with its
slower solution. Will favor the EC/NAM which decreases snow Monday
morning with just some higher elevation snow showers by Monday
afternoon. Snowfall amounts look to be generally in the 3-6 inch
range over se Wyoming above about 5000 feet outside of the mtns,
with 6-12 inches or so over the mtns. Winds not looking too strong
though so blowing snow should be rather limited. Clearing out
Monday night with cold temperatures Tuesday morning, well into the
teens and 20s across the CWA. Rest of the week then looks mild
and mainly dry with temps close to seasonal averages.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1139 PM MDT Fri Oct 6 2017
Mainly vfr conditions through the taf period. Mvfr vis will be
possible at AIA for the next few hours. Strong west winds will be
the main aviation concern over especially southeast WY. The period
of highest winds will be from 15-00Z with gusts to 35-40 kts.
Winds will generally be weaker over the Nebraska Panhandle,
however a few gusts to 25-30 kts could occur by Saturday
afternoon.
&&
.FIRE WEATHER...
Issued at 309 PM MDT Fri Oct 6 2017
A Fire Weather Watch has been issued for FWZs 301, 309 and 310 for
strong winds and low humidities from 11 AM until 7 PM MDT Sat. The
main area of concern will be from the Laramie Range, eastward into
the I-25 corridor from Douglas to the CO State Line. A significant
downsloping wind is expected with widespread gusts of 45 to 55 MPH
(or higher) and RH values as low as 10 percent. No concerns beyond
Saturday with the arrival of colder air and accumulating snow over
much of the area by Sunday night.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 6 PM MDT Saturday for WYZ106-110-116-117.
Fire Weather Watch from 11 AM MDT Saturday through Saturday
evening for WYZ301-309-310.
High Wind Watch from 3 AM MDT Saturday through Saturday morning
for WYZ118.
NE...None.
&&
SHORT TERM...CLH
LONG TERM...RE
AVIATION...ZF
FIRE WEATHER...CLHHazardous Weather Outlook National Weather Service Cheyenne WY 323 AM MDT Fri Oct 6 2017 WYZ101>119-070930- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen 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- 323 AM MDT Fri Oct 6 2017 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Windy conditions will develop tonight and persist through Saturday afternoon. The strongest winds will be in the wind prone areas of southeast Wyoming where gusts to 60-65 mph are possible and a High Wind Watch is in effect. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A strong cold front will move through the region Sunday evening, bringing a good chance of accumulating snow to areas above 5000 feet on Sunday night into Monday morning. .Spotter information statement... Spotter activation will not be needed. NEZ002-003-019>021-054-055-095-096-070930- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 323 AM MDT Fri Oct 6 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...SATURDAY THROUGH THURSDAY A strong cold front will move through the region Sunday evening, potentially bringing accumulating snow to areas above 5000 feet on Sunday night into Monday morning. .Spotter information statement... Spotter activation will not be needed.
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</html>The national radar mosaic for the moment the first event began.
21 high wind. Local standard time, as filed.
The WYDOT sensor at Arlington measured sustained winds of 40 mph or higher, with a peak gust of 65 mph at 06/2310 MST.
The WYDOT sensor at Arlington measured sustained winds of 40 mph or higher, with a peak gust of 65 mph at 07/1345 MST.
The WYDOT sensor at Arlington East measured sustained winds of 40 mph or higher, with a peak gust of 62 mph at 07/0640 MST.
The WYDOT sensor at Otto Road measured sustained winds of 40 mph or higher, with a peak gust of 59 mph at 07/0740 MST.
The WYDOT sensor at Halleck Ridge measured sustained winds of 40 mph or higher, with a peak gust of 66 mph at 07/1250 MST.
The WYDOT sensor at Dale Creek measured wind gusts of 58 mph or higher, with a peak gust of 73 mph at 07/1125 MST.
The WYDOT sensor at Vedauwoo measured wind gusts of 58 mph or higher, with a peak gust of 75 mph at 07/1345 MST.
The wind sensor at the Elk Mountain Airport measured sustained winds of 40 mph or higher, with a peak gust of 61 mph at 07/1315 MST.
The WYDOT sensor at Interstate 80 mile post 353 measured a peak wind gust of 58 mph.
The WYDOT sensor at Bordeaux measured wind gusts of 58 mph or higher, with a peak gust of 75 mph at 07/1255 MST. A couple of semis were blown over near Interstate 25 mile post 71.
The WYDOT sensor at Lone Tree measured wind gusts of 58 mph or higher, with a peak gust of 70 mph at 07/1150 MST.
The UPR sensor at Buford measured wind gusts of 58 mph or higher, with a peak gust of 74 mph at 07/1045 MST.
The WYDOT sensor at Elk Mountain measured sustained winds of 40 mph or higher.
The WYDOT sensor at Buford East measured sustained winds of 40 mph or higher, with a peak gust of 67 mph at 07/1130 MST.
The WYDOT sensor at Wagonhound measured sustained winds of 40 mph or higher, with a peak gust of 63 mph at 07/1525 MST.
The WYDOT sensor at Foote Creek measured sustained winds of 40 mph or higher, with a peak gust of 60 mph at 07/1215 MST.
A RAWS sensor near Muddy Gap measured wind gusts of 58 mph or higher, with a peak gust of 75 mph at 07/1650 MST.
The WYDOT sensor at Coleman measured sustained winds of 40 mph or higher.
The WYDOT sensor at Shirley Rim measured sustained winds of 40 mph or higher.
The WYDOT sensor at Deer Creek measured a peak wind gust of 58 mph.
The WYDOT sensor at Interstate 80 mile post 249 measured a peak wind gust of 63 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, October 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 2026-10-01. Each event’s entry at NCEI: 724904, 724905, 724903, 724920, 724910, 724916, 724918, 724907, 724919, 724902, 724917, 724915, 724906, 724914, 724912, 724909, 724805, 724806, 724803, 724802, 724911.