A strong, slow-moving low pressure system moved across southeast Wyoming and produced widespread moderate to heavy snowfall. Wind gusts to 30 mph created areas of drifting snow and poor visibility.
Every event with a place to put it; 34 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 strong, slow-moving low pressure system moved across southeast Wyoming and produced widespread moderate to heavy snowfall. Wind gusts to 30 mph created areas of drifting snow and poor visibility. Storm total snowfall ranged from 6 to 18 inches, heaviest over the Snowy Range.
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 Feb 17, 4:45 PM MST, 1 hour 15 minutes earlier.
Area Forecast Discussion
National Weather Service Cheyenne WY
445 PM MST Sat Feb 17 2018
.SHORT TERM...(Tonight - Monday Night)
Issued at 252 PM MST Sat Feb 17 2018
An extremely active period of weather across southeast Wyoming and
the western Nebraska Panhandle over the next 24-48 hours. Concerns
remain focused on strong winds through tonight, and the threat for
significant snowfall on Sunday and Monday.
A few wind gusts around 60 MPH have been observed around Arlington
this afternoon, but generally speaking most areas have remained at
or below 50 MPH with fairly modest flow aloft. We still anticipate
a dramatic up-tick in wind speeds overnight as a fairly strong sfc
low tracks across northeast WY into western SD. H7 and H85 CAG-CPR
gradients climb to between 80 and 90 meters as this happens, along
with H7-H8 flow of 55-65 knots over much of southeast WY and 65-75
knots over the N. Laramie Range. Significant downward omega should
support widespread strong wind gusts over the wind prone areas, as
well as some adjacent plains/valley areas as well. We extended our
High Wind Warnings through 16z as flow aloft remains elevated into
mid Sunday morning. After that, the high wind threat should slowly
diminish with an approaching cold front and weakening gradients. A
blustery day is likely Sunday along/w of the Laramie Range, but it
appears winds will remain below criteria at this time. Next couple
of shifts will want to re-evaluate, however.
Attention then shifts to our Winter Storm Potential. There is some
potential for snow to begin as early as mid Sunday morning, mainly
across northern Converse county w/ the initial passage of the cold
front. This initial period of snow may be fairly heavy, with model
guidance suggesting very strong frontogenesis along w/ a favorable
position of the upper jet. That said, we upgraded those areas to a
Winter Storm Warning with this package and opted to include higher
elevations in the N. Laramie Range and Ferris/Seminoe Mountains as
well. Special thanks to WFOs UNR and RIW for the coordination this
afternoon in making a decision to upgrade. Otherwise, this appears
likely to be a widespread significant snowfall as the RRQ of a 120
knot H25 jet traverses the CWA. Snow is likely to spread southeast
across the area through the day, and in general become heaviest in
the Sunday night/Monday time frame with impressive frontogenesis &
strong upper level dynamic support. Consensus guidance and WPC are
all looking very reasonable with widespread 8-12 inch amounts with
locally higher totals in the mountains. Slightly lower amounts are
expected from the Cheyenne area into the S. Panhandle, but we will
still likely have Advisory level amounts. NAM soundings also would
suggest some potential for a period of light freezing drizzle late
Sunday night for these areas, while the GFS is colder and suggests
predominantly snow. Will need to keep an eye on this as well. Kept
Winter Storm Watches generally as-is, but decided to include areas
from Torrington/Goshen county toward Alliance/Box Butte county for
expected amounts in the 4-8 inch range through Monday night.
Dangerous wind chills are also likely on Sunday night, but more so
Monday night with snow ending and deeper cold air in place.
.LONG TERM...(Tuesday - Saturday)
Issued at 252 PM MST Sat Feb 17 2018
No major forecast concerns through the remainder of next week. The
upper-level pattern favors a few passing weak disturbances, but we
expect these to be fairly dry systems with limited chances for any
precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday afternoon)
Issued at 445 PM MST Sat Feb 17 2018
Strong westerly winds with gusts 35-50 kt will continue to be the
primary aviation concern across southeast Wyoming through early
Sunday morning, especially along and west of Interstate 25. Moderate
to severe mountain wave turbulence can be expected. Introduced VCSH
at Rawlins beginning 15Z Sunday, with MVFR-IFR conditions developing
in light snow and fog from east central Wyoming to the northern
Nebraska Panhandle behind an Arctic cold front after 20Z. There will
be occasional mountain obscurations from snow shower activity.
&&
.FIRE WEATHER...
Issued at 313 AM MST Sat Feb 17 2018
Strong winds continue today ahead of an approaching arctic front
moving into the area from the north. Will see widespread strong
winds through the day today into this evening. By Sunday late
morning, we begin to see the front move into Converse and Niobrara
Counties with winds shifting north and northeast behind the front.
Widespread moderate snow and much colder air moving in behind the
front. Just about every location in southeast Wyoming and Nebraska
panhandle are going to see snow accumulations with the most
significant along and north/west of a line from Chadron to
Wheatland to Buford. Snow continues into Tuesday before ending.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Watch from Sunday evening through Monday evening
for WYZ106>117.
High Wind Warning until 9 AM MST Sunday for WYZ104>107-109-110-
113-115>117.
Winter Storm Warning from 9 AM Sunday to midnight MST Monday
night for WYZ101-103>105.
High Wind Warning until 9 AM MST Sunday for WYZ101-103.
Winter Storm Watch from Sunday morning through Monday evening
for WYZ102.
NE...Winter Storm Watch from Sunday evening through Monday evening
for NEZ002-003-095-096.
&&
SHORT TERM...CLH
LONG TERM...CLH
AVIATION...MAJ
FIRE WEATHER...GCCHazardous Weather Outlook...CORRECTED National Weather Service Cheyenne WY 518 PM MST Sat Feb 17 2018 WYZ101>119-190030- 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- 518 PM MST Sat Feb 17 2018 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TONIGHT Strong west to southwest winds will continue across portions of south central and southeast Wyoming tonight, mainly along and west of Interstate 25 tonight where High Wind Warnings remain in effect. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY The strong winds will ease Sunday morning as an Arctic cold front slowly progresses south across the area. Light rain and snow showers will develop ahead of the front, with snow gradually increasing in coverage and intensity behind the front Sunday afternoon through Monday. A prolonged period of moderate to heavy snow will occur behind the front, leading to adverse travel conditions Sunday night and Monday. Winter Storm Watches and Warnings are in effect from Sunday morning through Monday evening for all except central and eastern Laramie County. The cold front will exit southeast Wyoming early Monday morning. Very cold temperatures and dangerous wind chills of 15 to 30 degrees below zero Monday through Tuesday may cause frostbite in less than 30 minutes to exposed skin. .Spotter information statement... Spotter activation will not be required at this time. NEZ002-003-019>021-054-055-095-096-190030- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 518 PM MST Sat Feb 17 2018 This hazardous weather outlook is for portions of western Nebraska. .DAY ONE...TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY An Arctic cold front is forecast to slowly move south through the Nebraska Panhandle late Sunday afternoon through early Monday morning. A prolonged period of moderate snow will occur along and behind the front. Significant snow accumulations are expected leading to hazardous travel conditions, especially across the northern Nebraska Panhandle where Winter Storm Watches have been issued. Winter Storm Watches may need to be expanded south into southern portions of the Panhandle as the event unfolds. Very cold temperatures and dangerous wind chills of 15 to 30 degrees below zero Monday through Tuesday may cause frostbite in less than 30 minutes to exposed skin. .Spotter information statement... Spotter activation will not be required at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
411 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0400 PM NON-TSTM WND GST ARLINGTON 41.59N 106.21W
02/17/2018 M53 MPH CARBON WY DEPT OF HIGHWAYS
0402 PM NON-TSTM WND GST WARREN AF BASE 41.15N 104.86W
02/17/2018 M59 MPH LARAMIE WY OTHER FEDERAL
0341 PM NON-TSTM WND GST 15 NE CENTENNIAL 41.45N 105.91W
02/17/2018 M59 MPH ALBANY WY DEPT OF HIGHWAYS
&&
BCHAPMANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
443 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0430 PM NON-TSTM WND GST BORDEAUX 41.95N 104.95W
02/17/2018 M50 MPH PLATTE WY DEPT OF HIGHWAYS
&&
BCHAPMANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
502 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0450 PM NON-TSTM WND GST ARLINGTON 41.59N 106.21W
02/17/2018 M61 MPH CARBON WY DEPT OF HIGHWAYS
SUSTAINED 45 MPH.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
526 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0515 PM NON-TSTM WND GST 7 NW ELK MOUNTAIN 41.76N 106.51W
02/17/2018 M59 MPH CARBON WY DEPT OF HIGHWAYS
HALLECK RIDGE WYDOT SITE. SUSTAINED 43 MPH.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
546 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0535 PM NON-TSTM WND GST ELK MOUNTAIN 41.69N 106.41W
02/17/2018 M57 MPH CARBON WY DEPT OF HIGHWAYS
0535 PM NON-TSTM WND GST 7 NW ELK MOUNTAIN 41.76N 106.51W
02/17/2018 M57 MPH CARBON WY DEPT OF HIGHWAYS
&&
BCHAPMANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
558 PM MST SAT FEB 17 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0552 PM NON-TSTM WND GST NE ESTERBROOK 42.41N 105.36W
02/17/2018 M58 MPH CONVERSE WY MESONET
&&The national radar mosaic for the moment the first event began.
34 winter storm. Local standard time, as filed.
A foot of snow was observed at Encampment.
The Old Battle SNOTEL site (elevation 10000 ft) estimated 12 inches of snow.
The Webber Springs SNOTEL site (elevation 9250 ft) estimated 12 inches of snow.
The Little Snake River SNOTEL site (elevation 8915 ft) estimated 12 inches of snow.
The Blackhall Mountain SNOTEL site (elevation 9820 ft) estimated 12 inches of snow.
The Sand Lake SNOTEL site (elevation 10050 ft) estimated 16 inches of snow.
The Medicine Bow SNOTEL site (elevation 10500 ft) estimated 18 inches of snow.
Seven inches of snow was observed at Rawlins.
Six inches of snow was measured a mile north of Rawlins.
None inches of snow was measured at Sinclair.
Six to eight inches of snow was observed in and around Baggs.
Twelve inches of snow was observed 15 miles northwest of Garrett.
Eight and a half inches of snow was measured at Shirley Basin.
Seven inches of snow was measured two miles south of Elk Mountain.
Seven inches of snow was measured two miles north-northeast of Encampment.
Six inches of snow was measured 29 miles north of Torrington.
Eleven inches of snow was measured at Elk Mountain.
Six inches of snow was measured near Muddy Gap.
Six inches of snow was observed at Rock River.
Eight inches of snow was observed 15 miles southwest of Wheatland.
Six inches of snow was observed at Vedauwoo.
Six inches of snow was observed between Federal and Horse Creek.
Nine inches of snow was measured 13 miles south-southwest of Manville.
Six inches of snow was observed at Wheatland.
Fourteen inches of snow was measured at Manville.
Nine inches of snow was observed 13 miles west of Lance Creek.
Ten inches of snow was observed at Lusk.
Thirteen inches of snow was observed at Keeline.
Ten inches of snow was measured five miles south of Douglas.
Seven inches of snow was measured a mile southwest of Glenrock.
Eight inches of snow was measured 11 miles northwest of Lost Springs.
Nine inches of snow was measured three miles east of Douglas.
Fourteen inches of snow was measured four miles north-northeast of Glenrock.
Eight and a half inches of snow was measured four miles west-southwest of Douglas.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2018Every state in 2018This day in weather historyWarnings in Wyoming, February 2018
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: 756081, 756060, 756061, 756062, 756063, 756064, 756065, 756083, 756084, 756089, 756090, 756100, 756101, 756102, 756103, 756104, 756105, 756106, 756107, 756108, 756110, 756111, 756113, 756115, 756117, 756118, 756119, 756120, 756121, 756122, 756123, 756124, 756125, 756126.