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FXUS65 KCYS 221953
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
153 PM MDT Wed May 22 2024

.KEY MESSAGES...

- Strong wind gusts 50-60mph possible in the wind prone and gap
  areas of southeast WY Thursday mid-morning through early
  afternoon. See the latest High Wind Watch Statement for
  further details.

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

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 149 PM MDT Wed May 22 2024

The low pressure system currently in Idaho will continue makings its
way eastward over the next 24 hours, bringing with it mainly strong
winds, but also cooler temperatures, mainly to northern and western
portions of the CWA. In addition, the precipitation will heavily
depend on the overall track of the low. As of now, models bring the
center of the low along the northern Wyoming border, keeping
southeast Wyoming and western Nebraska mostly dry. In areas that do
receive precipitation, it will likely not be significant amounts,
less than 0.10 inches. NBM is showing 30 to 60 percent probabilities
of 24 hour rainfall amounts greater than 0.01 inches. The greater,
more impactful, threat is expected to be the winds. Opted to keep
the High Wind Watch in effect instead of upgrading it because the
probabilities of high winds is still very marginal and heavily tied
to the frontal timing and positioning. The best chances for high
winds are going to be along and just east of the North Laramie
Range. Internal guidance did trend upward in the high wind chances
near Coleman and Bordeaux along Interstate 25 with 40 to 60 percent
probabilities. Looking at hi res guidance, there is high confidence
in frequent gusts along and just behind the front of 45-50+ mph, it
is really a matter of reaching the 58 mph (50 knot) criteria. The
NBM has near 10 to 20 percent probabilities of greater than 50 mph
wind gusts Thursday late morning through afternoon, with nearly 0
percent probabilities of greater than 60 mph wind gusts. That being
said, it is certainly not out of question, there is just low
confidence that there will be enough subsidence to mix down 60+ mph
wind gusts to the surface.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 149 PM MDT Wed May 22 2024

Friday will be on the cooler side behind Thursday`s passing system
with afternoon highs running ~5F degrees below normal for late May,
primarily in the 60s. Could see a few showers develop late in the
afternoon Friday near the CO/WY border with northeast post-frontal
upslope flow into the Front Range and a weak shortwave passing in
the westerly flow aloft.

Looking at an overall active pattern headed into this weekend with
multiple weak shortwave passages. It does not appear like any
significant, long duration troughing or ridging patterns setup over
the Intermountain-West leading to fairly steady temperatures with
daily chances for showers and thunderstorms through Monday.
Temperatures will remain steady in the 60s to low-70s.

500mb height rises beginning around the middle of next week could
lead to warmer and drier conditions, however model uncertainty
exists with the timing of the onset of this pattern. GEFS members
are a little stronger with the 500mb ridge development while EC
members generally keep flow aloft more zonal with the polar jet
running closer to the Canadian border rather than lifting up into
central Alberta.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
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.

&&

.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...LEG
LONG TERM...MB
AVIATION...MB