With the recent passing of a low pressure trough, cold arctic air settled in across the region bringing wind chill values into the minus 30 and 40 degree range.
Every event with a place to put it; 10 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.
With the recent passing of a low pressure trough, cold arctic air settled in across the region bringing wind chill values into the minus 30 and 40 degree 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 6, 10:53 AM MST, 7 minutes earlier.
Area Forecast Discussion
National Weather Service Cheyenne WY
1053 AM MST Wed Feb 6 2019
.SHORT TERM...(Today through Friday)
Issued at 330 AM MST Wed Feb 6 2019
Plethora of forecast issues this morning for the short term as a
winter storm system moves through the area. Concerns deal with
snow amounts today and tonight...followed by bitter cold
temperatures and windchills tonight into Thursday.
Currently...This mornings water vapor imagery showing cyclonic
ration in the upper levels over northeastern Nevada and
northwestern Utah. This low pressure system slowly tracking east.
Plumes of moisture being pulled up from the southwest ahead of
this low. First band just off to the west of Rawlins over
Sweetwater County down into northeast Utah. Another over
southeastern Idaho just ahead of the low. At the surface...the
stationary front still hangs over central Colorado roughly along a
line from Denver...north to Laramie...then northwest to Riverton
and finally up into extreme western Montana. Current temperatures
over the northern Panhandle ...4 degrees at Chadron...5 at Casper.
Below zero temperatures further north over Montana and
northeastern Wyoming.
Winter headlines today look on tracks and have not made any
changes for todays headlines. Did get a report from Rawlins
Sheriff office of 4-5 inches of snow in Rawlins last night at
1123PM. With another band of snow over Sweetwater
County...warnings out that way should easily verify later this
morning.
Widespread upper level diffluence expected later this morning and
afternoon as the upper low tracks into northwestern Colorado. This
expected to create widespread snow across the CWA after 18Z that
will continue through at least 03Z this evening. Need to be
watching the Panhandle as GFS and NAM hinting at band of quarter
inch plus qpf from Cheyenne to Chadron towards 00Z. May need a
short fused warning for heavier snow bands. HIRES guidance
hinting at a heavier band from Scottsbluff to Cheyenne around 22Z.
Dayshift will need to monitor closely.
Bottom falls out of temperatures tonight into Thursday morning
with 700mb temperatures falling from -3C here at Cheyenne
currently to -21C this time Thursday morning. Thinking currently
is once the snow ends tonight...temperatures are really going to
tank. All areas falling well below zero for overnight lows as low
level winds shift to northwest at 15 to 20kts just off the
surface. Getting -40F windchills over Niobrara County with -30F
down here at Cheyenne after 06Z tonight. Decided on a Windchill
Watch to cover much of the CWA through 18Z Thursday.
Slow warmup Thursday afternoon into Friday as 700mb temperatures
climb back to around -10C by Friday morning. Depending on
snowpack and clearing skies...temperatures are once again going to
be a challenge for Friday morning as 700mb winds decrease to
10-15kts.
.LONG TERM...(Friday night through Tuesday)
Issued at 330 AM MST Wed Feb 6 2019
Friday night/Saturday...Southwest flow aloft strengthens as the next
shortwave trough aloft approaches from Utah, which will help the
next Canadian cold front to slowly move southward across our
northeast counties Saturday afternoon, producing a colder day there.
Elsewhere, temperatures will be slightly warmer than Friday.
Sunday...Will be a colder day in the wake of the progressive
shortwave trough aloft and its associated cold frontal passage. Will
see a chance of snow early in the day, though amounts will be
limited due to the brisk movement of the trough aloft.
Monday...Another fast moving shortwave trough aloft and its
associated cold front will move into our western counties in the
afternoon bringing colder weather there, though everywhere else will
be slightly warmer in the warm sector ahead of the cold front. Snow
chances will be limited due to minimal low and mid level moisture.
Tuesday...Breezy to windy, and slightly warmer as fast zonal flow
aloft develops and downslope west winds occur at the surface. Dry
weather prevails due to limited low and mid level moisture.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1047 AM MST Wed Feb 6 2019
Weather conditions continue to deteriorate across the area as
upslope snow and fog have developed this morning. Visibility for
most terminals was between 1/2 to 2sm with snow and freezing fog.
Expect these conditions to continue through 2300z. Aviators use
extreme caution in and around terrain as low ceilings and
visibility will obscure terrain. Winds from the north will
increase greatly after 00z. Hi res models show snow begining to
end from west to east at RWl near 23-03z with isolated shower
activity there after. Snow will continue through the night ending
between 10 and 14z at CYS and LAR. Expect snow to continue
through the first part of the morning for the panhandle taf
sites. Celings will remain low tomorrow with BKN to OVC skies at 2
to 4 thousand feet and fog. gradual improvements are expected
there after but flying weather remains treacherous for the time
being.
&&
.FIRE WEATHER...
Issued at 330 AM MST Wed Feb 6 2019
Widespread accumulating snow event ongoing this morning which will
last through early Thursday morning. Low pressure system currently
over northeastern Nevada and northwestern Utah will slowly tracks
across southern Wyoming and Northern Colorado the next 24
hours...bringing all areas measurable snowfall. As the low exits
east Thursday morning...bitterly cold temperatures and windchills
will develop. No fire weather concerns expected through the
weekend as all areas should have existing snowpack and cold
temperatures. Next snow event still on track for Sunday as another
front moves into the area.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 6 AM MST Thursday for WYZ106>108-
115>119.
Wind Chill Watch from this evening through Thursday morning for
WYZ101>103-105>108-110-114>119.
Winter Weather Advisory until 11 PM MST this evening for WYZ105-
113.
Winter Storm Warning until 11 PM MST this evening for WYZ104-
109>112-114.
Winter Weather Advisory until midnight MST tonight for
WYZ101>103.
NE...Winter Weather Advisory until 6 AM MST Thursday for NEZ002-003-
019>021-054-055-095-096.
Wind Chill Watch from this evening through Thursday morning for
NEZ002-003-019>021-054-055-095-096.
&&
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...ADL
FIRE WEATHER...GCC<!doctype html>
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</html>The national radar mosaic for the moment the first event began.
10 extreme cold/wind chill. Local standard time, as filed.
Union Pacific Railroad sensor at Rock River measured wind chills in the minus 30 to even the minus 40 range.
The Dodge Creek and Esterbrook sites both measured wind chill values in the minus 30 to minus 35 range.
Wyoming Department of Transportation sensor at Coleman or eight miles south of Sibley Peak measured wind chill values in the minus 30 to minus 34 range.
Union Pacific Railroad sensor twelve miles south of Van Tassell measured wind chills in the minus 30 to minus 35 range.
Union Pacific Railroad sensor located seven miles west-northwest of Van Tassell measured wind chills in the minus 30 to minus 35 range.
Several Wyoming Department of Transportation sensors along Interstate 80 measured wind chills in the minus 30 to even minus 40 range from Vedauwoo to Buford.
Wyoming Department of Transportation sensors along Interstate 80 by Arlington and Elk Mountain measured wind chills in the low minus 30 range.
Wyoming Department of Transportation sensors near Whitaker and southwest of South Greeley High measured wind chill values around minus 31.
Wind chills ranging from minus 30 to minus 35 measured at the Union Pacific Railroad sensor five miles west-northwest of Burns.
Wyoming Department of Transportation sensor at Deer Creek along Interstate 25 east of Casper measured wind chill values in the minus 30 to minus 34 range.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2019Every state in 2019This day in weather historyWarnings in Wyoming, February 2019
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: 805804, 805809, 805802, 805803, 805805, 805826, 805811, 805831, 805799, 805800.