High Wind in Wyoming, February 28, 2024

Area Forecast Discussion
National Weather Service Cheyenne WY
1040 PM MST Tue Feb 27 2024

.KEY MESSAGES...

- Snow ending this evening. Strong winds returning to the wind
  prone areas of southeast WYoming tonight through Wednesday.

- Mild temperatures will return for Thursday through Saturday,
  with strong winds again looking increasingly likely for the
  wind prone locations of southeast Wyoming for Friday and
  Saturday.

- Another round of heavy mountain snow possible Saturday through
  Monday with much colder temperatures. Light to moderate snow
  possible in valleys and lower elevations.

&&

.UPDATE...
Issued at 616 PM MST Tue Feb 27 2024

The last round of snow showers combined with breezy winds is
quickly advancing across extreme portions of southeast WY early
this evening. Expect coverage to dissipate quickly in the next
couple of hours as we have surface high pressure sweeping
towards our cwa. The cold air continues to be entrenched across
the region, but partial cloud cover will limit most areas to
single digits and teens for overnight lows. The remainder of the
forecast is on track as we quickly transition to gusty winds in
the wind prone areas overnight.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 230 PM MST Tue Feb 27 2024

Cold front lays along a line from north central Colorado...north
to Laramie...then west northwest to Medicine Bow and Muddy Gap.
Getting some pretty healthy snow showers developing along this
front with a line moving through northern Laramie County at this
time. HRRR simulated radar seems to be picking up this activity
pretty good on timing and location this afternoon.

Kept winter headlines going this afternoon for Arlington and the
Snowy/Sierra Madre Ranges. SNOTELS still picking up some SWEs
and we have seen low visibilities on and off out near Arlington
this afternoon. Decided to let the winter headlines continue
through expiration time.

HRRR simulated radar continues to show snow shower development
roughly from Shirley Basin...southeastward to Cheyenne after 00Z
for a time before lifting northeast and eventually dissipating
through the late evening. Winds shift back to the west this
evening as upper shortwave shifts southeast. Gradients begin to
increase this evening as winds shift westerly. Craig to Casper
850/700mb height gradients near Arlington up near 58/53mtrs at
03Z...increasing to near 90/74mtrs by 12Z Wednesday. Random
Forest high wind guidance shows a marked increase in high wind
chances up near 40 percent by 03Z and 90 percent by 12Z out at
Arlington. Bordeaux up near 30 percent by 06Z and 50 percent by
12Z. GFS 700/750mb winds increase to 60kts/50kts after 06Z. Decided
to upgrade watches to warnings for the wind prone areas.

Later shifts will need to watch the surrounding forecast zones
around the wind prone areas...namely WYZ 115 (Laramie) and 118
(Cheyenne) for possibly short fused high wind warnings. GFS
soundings showing 45kts forecast just off the surface at both
Cheyenne and Laramie. Gradients as strong as forecast usually do
result in some spillage of high winds out into adjacent
zones...so evening and mid shift may want to consider including
these zones.

Winds look to ease Wednesday afternoon over the Summit and by
Bordeaux. Local WRKHGT product still showing strong wins out
west by Arlington and Muddy Gap through 12Z Thursday before they
ease...so ending times of these warnings run through 12Z
Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 230 PM MST Tue Feb 27 2024

Warm temperatures and gusty to strong winds remain the story until a
cold front moves through Saturday night followed by a stronger cold
front Sunday bringing much colder temperatures, heavy mountain snow,
and potentially light to moderate snow at lower elevations and
valleys.

Forecast high temperatures Friday and Saturday with ridging and
strong westerly, downsloping flow, are sitting in the 40s to low 50s
west of the Laramie Range and 50s to low 60s east of the Laramie
Range. These temperatures in the High Plains are 15 to 20 degrees
above-normal for the end of February! Wind gusts are expected to
remain elevated through Friday night before starting a downward
trend. Internal guidance has 40 to 60 percent probabilities of high
winds (greater than 58 mph wind gust and/or sustained 40+ mph for 1
hour) near Arlington and Bordeaux and near 20 percent in the South
Laramie Range. For now, the highest confidence is in wind gusts 40
to 50 mph with brief periods of 55+ mph wind gusts through Friday
afternoon.

The pattern change comes over the weekend. Most long range guidance
has the low staying well north of the forecast area, which typically
means heavy mountain snow, light to moderate snow in valleys, and
breezy conditions. Looking at ensemble clusters, even the most
aggressive solutions still only have 1 to 3 inches of snowfall in
valleys and lower elevations. Highest confidence at this time is in
much colder temperatures starting Saturday night. Ensembles are
generally in agreement showing the initial, weaker cold front
pushing through Saturday evening with low temperatures 5 to 15
degrees cooler than the previous night's. Then, the stronger cold
front moving into southeast Wyoming and western Nebraska Sunday
afternoon. Low temperatures Sunday night are forecast to be in the
low teens to 20s, and high temperatures Monday in the mid 20s to 30s
with the warmest temperatures in the High Plains. Snowfall in the
mountains will likely persist from Saturday afternoon through Monday
afternoon. In the High Plains, the best chance for snowfall based on
the current frontal timing is Sunday night through Monday.
Confidence remains low in snowfall amounts though. Confidence should
increase Friday into Saturday as the low makes its way into the
Pacific Northwest.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1040 PM MST Tue Feb 27 2024

The Upper level trough that brought some snow to the region on
Tuesday will continue to push east across the Great Plains tonight.
Occasionally breezy or windy conditions expected through Wednesday
afternoon with mostly sunny skies.

HAZARDS/WEATHER TRENDS: CIGS have lift or dissipate across most of
the area with VFR conditions expected for the rest of tonight and
through Wednesday. Localized MVFR CIGS have held on near KAIA
tonight, but are expected to dissipate shortly by 08z. Windy
conditions will redevelop for KRWL, KLAR, and KCYS and continue
through most of Wednesday with gusty westerly winds. 30 to 40 knots
gusts are expected, with gusts up to 25 knots for the western
Nebraska terminals.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 1 AM Wednesday to 5 AM MST Thursday for
     WYZ104.
     High Wind Warning from 1 AM to 5 PM MST Wednesday for WYZ106.
     High Wind Warning until 5 AM MST Thursday for WYZ110.
     High Wind Warning from 11 PM this evening to 2 PM MST
     Wednesday for WYZ116-117.
NE...None.

&&

UPDATE...BW
SHORT TERM...GCC
LONG TERM...LEG
AVIATION...TJT

Preliminary Local Storm Report
National Weather Service Cheyenne WY
1039 PM MST Tue Feb 27 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0600 PM     Snow             9 SSW Arlington         41.46N 106.28W
02/27/2024  E12.8 inch       Carbon             WY   Park/Forest Srvc

            SAND LAKE SNOTEL IN THE SNOWY RANGE.
            ELEVATION 10098 FEET. SNOW WATER EQUIVALENT
            IS 0.8 INCHES AND THE SNOW TO LIQUID RATIO
            USED WAS 16 TO 1. ACCUMULATION WAS OVER 22
            HOURS. CRITERIA REACHED AT APPROX. 02/27
            8:00.

0600 PM     Snow             14 WNW Centennial       41.38N 106.35W
02/27/2024  E15.0 inch       Carbon             WY   Park/Forest Srvc

            MEDICINE BOW SNOTEL IN THE SNOWY RANGE.
            ELEVATION 10512 FEET. SNOW WATER EQUIVALENT
            IS 0.9 INCHES AND THE SNOW TO LIQUID RATIO
            USED WAS 17 TO 1. ACCUMULATION WAS OVER 24
            HOURS. CRITERIA REACHED AT APPROX. 02/27
            7:00.

&&