-- Discussion containing changed information from previous version are highlighted. --
767
FXUS65 KCYS 221743
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1143 AM MDT Wed May 22 2024

.KEY MESSAGES...

-- Changed Discussion --
- Strong wind gusts up to 60mph possible in the wind prone and
  gap areas of southeast WY on Thursday. See the latest High
  Wind Watch Statement for further details.

- Daily shower and thunderstorm chances continue through the
  long term from Thursday afternoon onwards.
-- End Changed Discussion --

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 330 AM MDT Wed May 22 2024

Lingering light rain showers have dissipated across western
Nebraska, and most clear skies have began to be the main story
early this morning. Surface temperatures across the valley
regions and high plains as of 9Z are in the low 30s to low 40s,
with the warmest temperatures along the North Platte River
Valley. Colder temperatures remain in the higher terrain, where
low to middle 20s have been observed.

As the day presses on, we will see a quiet weather day with
mostly sunny skies and warmer temperatures. It will take some
time to warm up for most locations as we will have a chilly
start, on the order of 10-15 degrees below normal for late May.
Patchy frost would not be a surprise for a few valley areas when
the workday begins for the public today. We will transition to a
weak zonal flow aloft across our cwa, which will assist with afternoon
highs reaching the 60s to middle 70s for the lower elevations.
By late afternoon, we will have a slight uptick is surface
pressure gradients, so elevated winds will begin to spread
across the region. The highest areas of confidence reside west
of the Laramie Range, where wind gusts up to 30-40mph are
anticipated.

A shortwave disturbance located over the Pacific Northwest
CONUS today, will propagate toward the Great Basin area by early
Thursday morning. As this happens, H5 flow aloft will
transition to a southwesterly regime. The upper level low center
will be located across north-central WY by 12Z Thursday. A
deepening surface low is progged to be realized in western SD by
midday Thursday. This is a familiar weather pattern for
stronger wind gusts to be realized across the wind prone and gap
areas of southeast WY. Omega fields coupled with 45-50+ knot at
700-800mb depict a weak mountain wave signature. Have gone with
a High Wind Watch to reflect this feature due to higher
confidence than 24 hours previously. It is still on the marginal
side of a wind signal, but we will see a steep surface pressure
gradient begin to occur on Thursday. Additionally, there will
be increasing cloud cover, CAA from a cold front, and
precipitation for our western zones. Have nudged temperatures
down for areas along and west of the Laramie Range. The stronger
wind gusts are expected to push further to the east, especially
into western NE by late Thursday afternoon into the early
morning hours. A windy day is in store for most of the area on
Thursday. Isolated to scattered rain showers will be possible
east of the Laramie Range by Thursday afternoon and evening, but
there is not a strong signal for organized thunderstorms to
occur.

Breezy to gusty winds will slowly wind down from west to east on
Friday morning. The aforementioned shortwave disturbance will
quickly trek to the east, giving way for a brief period of quiet
weather. This will be a short window however, as the next
shortwave disturbance further upstream will arrive by Friday
afternoon and evening. Daytime highs on Friday will be seasonal,
remaining in the 60 to 70 degree range for the high plains, and
cooler in the mountain zones. Stay tuned for updates in the
short term regarding the potential for strong winds as we get
closer to time that they will be present on Thursday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Issued at 330 AM MDT Wed May 22 2024

Shortwave ridging across the CWA Saturday night that tracks east
Saturday morning. as the ridge axis shifts east...the
ECMWF...GFS and SREF guidance shows showers developing across
Carbon County early Saturday morning as next shortwave trough
begins moving into the CWA. Confidence is increasing on this
happening...so increased PoPs Friday night into Saturday.

Associated surface front hangs around the CWA through the
weekend for showers and thunderstorms. Stronger upper low moves
through Saturday night into Sunday morning. Have pretty high
PoPs (60-70%) chances for Saturday and Saturday night.

Finally dry out Sunday night into Monday as upper ridging builds
back in from the southwest.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
-- Changed Discussion --
Issued at 1135 AM MDT Wed May 22 2024

VFR conditions currently across area terminals with increasing
upper level cloud cover showing up on latest satellite imagery
and will continue into this afternoon. Gusty winds expected this
afternoon around 25-35 kt for southeast WY terminals and around
20 kt across the NE panhandle. Additionally, strong southerly
winds look to develop tonight across northern portions of the NE
panhandle with a strengthening nocturnal LLJ as KCDR could see
gusts around 35 kt overnight. A cold front approaching from the
west Thursday morning will bring gusty winds throughout the day
along with a chance for light precipitation near KRWL. Latest
HREF guidance show probability of MVFR ceilings around 30%
briefly near KRWL Thursday morning.
-- End Changed Discussion --

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from Thursday morning through Thursday
     afternoon for WYZ101-106-107-110-116-117.
NE...None.

&&

$$

SHORT TERM...BW
LONG TERM...GCC
AVIATION...MB