779
FXUS65 KCYS 010540
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1140 PM MDT Sun Aug 31 2025

.KEY MESSAGES...

- Drier conditions expected to return Sunday and through much of
  next week with a warming trend bringing closer to near normal
  temperatures by early in the week.

- The probability for widespread hazardous weather is low.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 150 PM MDT Sun Aug 31 2025

Quiet conditions expected over the next 48 hours as high
pressure ridging continues to overspread the region from the
west, keeping precipitation chances near to nil and the overall
pressure gradient fairly weak. This will promote a gradual
warming trend, with temperatures coming back to closer to near
normal with highs in the mid 70`s to mid 80`s by Monday.
Meanwhile winds will remain generally on the light to breezy
side, with speeds across the region gusting around 15-25 mph
today and tomorrow under a diurnally driven northerly flow. The
troughing off to our east may be able to produce a passing
shower or weak thunderstorm today that could move near or across
Chadron this afternoon or evening, but the overall risk remains
at a slight chance at the very best, and by tomorrow all
precipitation chances will be well outside of our CWA. Finally,
some smoke could begin to creep in to our western zones thanks
to wildfires further west, and low clouds into locally patchy
fog may occur overnight into tomorrow morning for the
northeastern Nebraska Panhandle with a favorable and moist low-
level inversion setting up, but this should be brief and clear
quickly after sunrise.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 150 PM MDT Sun Aug 31 2025

Ridging aloft across the western CONUS continues to hold firm at the
start of the long term, bringing pleasant weather for most of the
CWA. This will allow drier air to flow into the region due to
northwest flow aloft, bringing limited chances of precipitation
along with generally cooler temperatures. Highest precipitation
chances will be confined to the Snowy and Laramie Ranges for
Tuesday, Wednesday, and again on Friday, while the remaining CWA
will remain relatively dry through the week with a return of
moisture over the weekend and an increasing threat of precipitation
across a majority of the CWA. Temperatures will top out in the 70s
to low 80s for most of the long term, except on Tuesday when we can
see the warmest day with highs climbing into the upper 70s across
the western zones while eastern Wyoming and the Nebraska panhandle
will enjoy the lower to upper 80s.

There is some disagreement in the global models with the evolution
of the ridge across the western CONUS and the strength of a stout
upper level low that drops south out of Canada into the Great Lakes
region by Wednesday, with the GFS being the strongest solution,
while the placement of the aforementioned features seems reasonable.
By the weekend, solutions diverge a bit with the placement and
timing of the two main synoptic features affecting our CWA in the
long term. Ensemble members show a bit of discrepancy too on how far
west the edge of a much cooler air makes it to our CWA due to the
upper level low coming out of Canada. GEFS members are mostly
clustered on an eastward position of the trough while the ECMWF
ensemble is more clustered westward. The GEFS solution would keep
temperatures near normal while the ECMWF ensemble would bring much
cooler temperatures into our CWA. Regardless of either ensemble
scenario, expect limited rainfall chances overall across most of the
CWA along with generally cooler temperature for the long term.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1140 PM MDT Sun Aug 31 2025

Upper level ridge axis across western Wyoming and Colorado will
dominate the weather pattern over the next day or two. This will
result in dry conditions and somewhat breezy northerly winds.

HAZARDS/WEATHER TRENDS: VFR conditions will continue for most
terminals tonight and Monday. There is a 15% to 25% chance for low
CIGS and some patchy fog for KCDR, KSNY, KAIA, and on the lower end,
KBFF between 08z and 14z this morning. Relatively low confidence in
these conditions becoming persistent through the early morning
hours, so kept MVFR to near IFR conditions for most of these
terminals. North to northeast winds will gust around 20 knots after
17z Monday.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...CG
LONG TERM...RZ
AVIATION...TJT