423
FXUS65 KCYS 302107
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
307 PM MDT Sat Aug 30 2025

.KEY MESSAGES...

- Scattered precipitation chances continue today, with drier
  conditions expected to return Sunday and through much of next
  week.

- Warming trend starts Sunday with temperatures closer to, or
  slight above, seasonal averages.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 210 PM MDT Sat Aug 30 2025

Scattered showers and storms ongoing this afternoon as the
trough begins to move out of the region. Modest instability
alongside PWAT values around 0.75-1 inch will continue to fuel
moderate to occasionally heavy downpours through this evening,
with rainfall rates approaching 1-2 inches per hour. A lack of
favorable support however should preclude strong to severe
storms, though an occasional stronger wind gust cannot be ruled
out.

Moving into Sunday the western ridge begins to overspread and
take control, drying our CWA out and bringing calm conditions
overall. Pressure gradients will be too weak to promote much
more than light winds, and with most notable forcing to our east
the only locations expected to see even a chance of
precipitation will be Dawes County, but this is a low-end chance
through the afternoon. With the ridging building we should also
see temperatures on the rise, though highs for the day should
still linger in the 70`s to low 80`s, remaining several degrees
below normal for this time of year.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 210 PM MDT Sat Aug 30 2025

Pleasant weather is in store to begin the week with limited chances
of precipitation coupled with cooler temperatures across the CWA.
One of the main synoptic features that will dominate weather
conditions here locally will be a stout ridge that builds aloft
across the western CONUS. This will allow drier air to flow into the
region due to northwest flow aloft along with with slightly below
normal temperatures. Temperatures will vary through the long term,
with highs generally topping out in the 70s, with the warmest days
being Monday and Tuesday, with temps climbing into the upper 70s
across the western zones while the eastern forecast zones will enjoy
the warmest temperatures as highs climb into the lower to mid 80s.
With drier air in place for the majority of the long term,
precipitation chances will be at a minimum.

Global model solutions seem reasonably aligned for the long term
with some subtle differences with the main features on the synoptic
scale, an upper level ridge that builds across the western CONUS and
a stout upper level low that dives south out of Canada into the
Great Lakes region by late Wednesday into early Thursday. Ensemble
members show a bit of discrepancy on how far west the edge of a much
cooler airmass 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 through most of the long term.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1148 AM MDT Sat Aug 30 2025

A mix of flight categories expected through tomorrow. Primarily
all sites will have a low risk of a passing shower or storm
which could briefly lower CIGs or VIS, but not expecting a long
duration event at any site. Otherwise, expecting a deck of low
clouds and possibly some BR at KCDR/KAIA tomorrow morning much
like this morning. Otherwise CIGs will be generally mid level,
around 8-10k feet. Winds around 5 to 15 knots, with some
occasional stronger gusts possible, particularly if a storm or
shower moves near or over a site. Storms expected through this
evening, weakening after the sun sets.

&&

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

&&

$$

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