High sustained winds occurred along the South Laramie Range Foothills on the morning of the 20th, including portions of Interstate 25 between Wheatland and the Colorado border.
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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.
High sustained winds occurred along the South Laramie Range Foothills on the morning of the 20th, including portions of Interstate 25 between Wheatland and the Colorado border.
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 20, 4:24 AM MST, 5 hours 2 minutes earlier. Its key messages:
Area Forecast Discussion
National Weather Service Cheyenne WY
424 AM MST Tue Feb 20 2024
.KEY MESSAGES...
1) Strong winds likely this evening and overnight across the
wind-prone areas, spreading east along the Interstate 25
corridor through the late evening.
2) Another round of mountain snowfall for south central Wyoming
Tuesday night through Thursday.
3) Unsettled weather continues with strong winds expected over
the weekend and into early next week.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 405 AM MST Tue Feb 20 2024
High Wind Warnings and Watches remain in effect early this
morning until 11 AM today. Current ASOS and WYDOT observations
across the region show south to southwest winds sustained
between 25 to 35 MPH with occasional gusts of 45 to 52
MPH...mainly around Arlington and Elk Mountain. A peak gust of
56 MPH was observed at county road 402 west of Arlington late
last night. Decided to keep the High Wind Watch out for this
zone and northern Carbon County. Can not rule out a few gusts
over 58 MPH, but confidence is still limited at this time. A few
of the typically windier locations are struggling to get gusts
over 25 MPH, further limited confidence in this event. Models
continue to show strong subsidence as the strong 150+ knot jet
to our south begins to influence the wind prone areas near
sunrise Tuesday. Should start to see increasing winds over the
I-80 corridor between Laramie and Cheyenne in addition to I-25
near Bordeaux. Kept the High Wind Warnings going for these three
zones, which have the best chance to see sustained winds over
40 MPH and/or gusts of around 60 MPH. Thankfully, the wind event
should be pretty short with winds just above the surface mixing
out by the afternoon hours. Outside of the wind prone areas,
winds will increase late this morning and into this afternoon
with westerly winds gusting between 30 to 45 MPH through this
afternoon. Models show a Pacific cold front moving eastward
into southern Wyoming this evening and into tonight, which
should gradually lower low level pressure gradients with snow
developing over Carbon and Albany counties.
Next forecast concern will relate to snowfall as we head into
tonight (Tuesday night) and Wednesday. Models remain uncertain
with the coverage of precipitation and any potential impacts
across mainly southeast Wyoming. Believe it will be warm enough
for all rain below 5500 feet if any precipitation makes it as
far east as the Wyoming/Nebraska border Wednesday and Wednesday
night. The NAM and ECMWF are in good agreement tonight, showing
a band of snowfall, likely associated with some low level
frontogenesis/frontal dynamics and the strong upper level jet
lifting northeast across the Front Range and into the central
plains by Wednesday. Models seem to have a good handle on the
upper level forcing, showing very good diffluence near the left
entrance region of the upper level jet max late on Wednesday and
Wednesday night. Peak diffluence seems to be located across
Carbon, Albany and western Platte and Laramie Counties during
this time period. However, the GFS and the GEFS ensembles are
still the driest solution(s) with only periods of snowfall even
in the mountains and little precipitation for the valleys and
high plains. High res models are starting to pick up on the
wetter ECMWF and NAM solutions, even though the SREF is still
showing a wide variety of outcomes in it's ensemble spreads.
Expect this to be a tricky forecast due to overall low
confidence with locally moderate to heavy snowbands. Would like
to note: model soundings and model 1km reflectively suggest CSI
(Conditional Symmetric Instability) snowbands, which fits the
current pattern pretty well with weak cyclogenesis to the south
and a strong upper level jet stream. Decided to increase POP
across most of Carbon county to start off and gradually
increased probabilities further east towards Wednesday night
near the Wyoming/Nebraska border. Highest confidence for the
higher mountains of southeast Wyoming, so issued a Winter
Weather Advisory for the Snowy Range and Sierra Madre Range.
Currently have warning snowfall amounts for the Sierra Madre
Range, but expect snowfall to come in waves and not be a steady
during the whole forecast period. In addition, these amounts
will be 48 to 60 hour snow totals. The tricky part is the
surrounding valleys and possibly high plains of western Platte
and Laramie Counties. Locations such as Rawlins, Saratoga,
southwest Carbon County should see some snow, but accumulations
may vary quite a bit. May need a Winter Weather Advisory shortly
for these locations with 2 to 4 inches of snow with locally
higher amounts due to banding. Further east, analysis of
overall dynamic forcing suggests the the NAM may be overdoing
liquid and snowfall amounts towards the I-25 corridor. Increased
snow accumulations up to one inch for Laramie, Cheyenne, and
south of Wheatland with ensemble means showing a quick band of
heavy snow associated with increasing frontogenesis.
Snow should come to an end early Thursday morning as the upper
level trough axis pushes eastward into the Great Plains.
Although colder temperatures are expected late Wednesday and
Wednesday night, it should still be near or slightly above
average for this time of the year. Clouds may be a little slow
to clear out early Thursday morning as models suggest, so kept
low temperatures mainly in the upper teens to upper 20s. If
skies clear out earlier, may be looking at temperatures about 10
degrees cooler than the current forecast.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 330 AM MST Tue Feb 20 2024
An unsettled pattern is expected through the remainder of the week
into the weekend. Zonal 250mb flow begins to amplify as an upper-
level ridge builds into the western CONUS Thursday into Friday. A
subtle 500mb shortwave traverses across the central CWA Thursday
afternoon, bringing with it the chance for mountain snow showers in
the Sierra Madre and Snowy Ranges. Southwesterly 700mb flow turns
westerly throughout the day as surface winds remain southwesterly.
Surface winds will be favorable for orographic lift producing snow
showers across the higher terrain. With average moisture for this
time of year combined with orographic lift will allow for snow
showers to develop across the higher terrain, but poor upper-level
support will minimize snow accumulation in the ranges. Snow chances
decrease significantly early Friday morning through the afternoon
hours as the upper-level ridge continues to push easterly. The upper-
level ridge will be firmly in place across the region by Saturday
with little to no precipitation chances expected.
Dry conditions are expected over the weekend, but the upper-level
ridge will be placed favorably for a 120kt westerly 250mb jet to set
up across the region. Similarly, at 500mb a modest jet will be
overhead with westerly flow throughout the middle atmosphere.
Looking further down, 700mb flow will also turn westerly with a 45kt
jet developing Saturday afternoon and strengthening to a 50kt jet by
Sunday morning. Vertical stacking of westerly flow Sunday will
combine to produce favorable conditions for strong winds at the
surface. Further supporting the strong winds, GFS downward omega
values are at a maximum across the Laramie Range near Bordeaux with
strong upward omegas just to the east. In house random forest
guidance suggests a 60% probability of high winds at Bordeaux on
Sunday. Similarly at Arlington, in house guidance suggests a 60%
probability of high winds on Sunday. 850mb Craig to Casper height
gradients soar to the upper-60s Sunday morning into the afternoon
hours with 700mb gradients not far behind in the upper-50s to low-
60s. Strong upward/downward/upward omega fields exist across the
high terrain Sunday afternoon favoring a mountain wave setup for
Arlington with a more downslope driven event at Bordeaux. These
parameters will need to be monitored over the next several days to
determine the probability for high winds as Saturday and Sunday
approach. For now, increased winds at Arlington and Bordeaux to near-
high wind criteria throughout Saturday and Sunday, with a longer
period of increased winds for Bordeaux. Luckily, with most wind
events across southeast Wyoming, temperatures on Sunday will be much
warmer than previous days with upper-50s east of the Laramie Range
to mid-60s across the Panhandle.
Another period of high winds will be possible Monday, with highest
chances at Bordeaux where in house guidance suggests a 50%
probability of high winds. GFS omega fields are once again maxed out
across the Laramie Range, but upper-level support is not as
favorable on Monday. The 700mb jet will remain rather strong, around
45kts, but southwesterly winds will dominate throughout the middle
and upper atmosphere resulting in decreased upper-level support.
Despite this, Monday still looks to be quite windy with near high
wind criteria winds for Bordeaux. More precipitation will be
possible across the CWA on Monday as a cold front pushes through and
drops temperatures from the mid-50s to low-60s on Monday to mid-30s
to 40s on Tuesday. This cold front will be associated with an upper-
level trough progged to push across the region Monday evening into
Tuesday. There is some disagreement between long range models on how
cold it will get with this next system. The GFS suggests 700mb
temperatures dropping back into the -14 to -16C range on Tuesday,
while the ECMWF keeps temperatures slightly warmer around the -10 to
-12C range. NAEFS mean 700mb temperatures support the -10 to
-12C range for Tuesday. Despite this disagreement, temperatures
are expected to drop significantly for the middle of the week.
Trends will need to be monitored to determine exactly how cold
it will get with this early-week system.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 419 AM MST Tue Feb 20 2024
VFR conditions expected for almost all terminals throughout the
TAF period. Primary aviation concern as of the 12Z TAF issuance
is the possibility for low level wind shear at all terminals,
except KRWL, through 16Z. As winds begin to increase later this
morning into the afternoon hours, low level wind shear will
decrease. Expect gusty winds at all terminals by the afternoon.
KRWL has the potential to see snow showers late in the TAF
period with MVFR conditions likely. KLAR may see snow showers
near the terminal, but confidence is low that snow will fall at
KLAR.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch until 11 AM MST this morning for WYZ104-110.
High Wind Warning until 11 AM MST this morning for WYZ106-116-
117.
Winter Weather Advisory from 5 PM this afternoon to 5 AM MST
Thursday for WYZ112-114.
NE...None.
&&
SHORT TERM...TJT
LONG TERM...AM
AVIATION...AMHazardous Weather Outlook National Weather Service Cheyenne WY 607 AM MST Tue Feb 20 2024 WYZ101-103>105-107-109-111>115-118-119-211315- Converse County Lower Elevations-North Laramie Range- Ferris/Seminoe/Shirley Mountains-Shirley Basin-East Platte County- Central Carbon County-Southwest Carbon County-Sierra Madre Range- Upper North Platte River Basin-Snowy Range-Laramie Valley- Central Laramie County-East Laramie County- 607 AM MST Tue Feb 20 2024 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Breezy conditions are expected today with west to southwest winds gusting up to 45 MPH at times. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A Pacific storm system will arrive Wednesday night and Thursday, bringing the chance for accumulating snowfall and colder temperatures to the area. .Spotter information statement... Spotter activation will not be needed. WYZ106-110-116-117-211315- Central Laramie Range and Southwest Platte County- North Snowy Range Foothills-South Laramie Range- South Laramie Range Foothills- 607 AM MST Tue Feb 20 2024 This hazardous weather outlook is for portions of south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT A High Wind Warning remains in effect this morning with westerly winds gusting between 50 and 60 MPH. Please see the High Wind Warning statement for further details. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY The potential for elevated to gusty winds being present for a majority of this week in the wind prone corridors. A weather system will arrive Wednesday night and Thursday, bringing the chance for accumulating snowfall and colder temperatures to the area. .Spotter information statement... Spotter activation will not be needed. NEZ002-003-019>021-054-055-095-096-WYZ102-108-211315- Dawes County-Box Butte County-Scotts Bluff County-Banner County- Morrill County-Kimball County-Cheyenne County- Northern Sioux County-Southern Sioux County-Niobrara County- Goshen County- 607 AM MST Tue Feb 20 2024 This hazardous weather outlook is for portions of panhandle Nebraska...east central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT No hazardous weather is expected. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY The probability of widespread hazardous weather is low. .Spotter information statement... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
WYDOT mesonet station Wyo Hill (KWYH) along Interstate 25 reported sustained winds over 40 MPH for over an hour 10 miles southwest of Cheyenne. Maximum wind gust was 54 MPH during this period.
WYDOT mesonet station Bordeaux (KBRX) along Interstate 80 measured sustained winds over 40 MPH for an hour 9 miles south of Wheatland. Maximum observed wind gust was 55 MPH during this period.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2024Every state in 2024This day in weather historyWarnings in Wyoming, February 2024
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: 1154661, 1154660.