Veteran, Wyoming Weather Forecast Discussion

978
FXUS65 KCYS 231914
AFDCYS
Area Forecast Discussion
National Weather Service Cheyenne WY
114 PM MDT Tue Sep 23 2025
.KEY MESSAGES...
- A cold front and Pacific storm system will bring much cooler
  temperatures and unsettled weather Tuesday. Mountain snowfall
  is expected above 8500 feet.
- A Freeze Warning is in effect for the high valleys west of the
  Laramie Range Wednesday morning. Freezing temperatures and
  frost possible.
- A ridge of high pressure aloft will lead to drier and warmer
  weather for Thursday through the weekend.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 104 PM MDT Tue Sep 23 2025
Radar still shows fairly good coverage of stratiform precipitation
across the southern half of the CWA early this afternoon. As the
upper-level low associated with this system slowly moves southeast
throughout the day, precipitation will taper off this afternoon from
north to south. A Winter Weather Advisory remains in effect for the
Snowy Range until 6 PM as areas above 8500 feet could see
accumulating snow through the afternoon. Webcams still show snow
falling, but as the afternoon progresses, a rain/snow mix will be
possible. While precipitation is expected to be stratiform for the
most part, cannot rule out a few convective showers/storms for areas
further north. Areas further north will see some sunshine later this
afternoon, leading to warmer temperatures and perhaps some
destabilization which could result in some convection. Most
precipitation will clear out of the CWA by the evening hours as the
upper-level low enters Kansas.
Clouds are also expected to clear out relatively quick later this
evening. Clearing skies combined with calm winds could cause
temperatures to tank overnight. Model guidance has done poorly on
anticipating the well below average high temperatures during the day
Tuesday. With cooler than expected temperatures during the day, it
will not take much for temperatures overnight to also drop below
model guidance. Went with a blend of the NBM 25th percentile
for overnight lows around freezing for areas west of the Laramie
Range. A Freeze Watch was already in effect for the high
valleys out west, so upgraded to a Freeze Warning with this
forecast package to account for the freeze potential. There is a
failure mode for temperatures to stay above freezing in these
areas overnight. Given the ample low-level moisture from the
precipitation, some models show fog developing in the valleys
which could keep lows from reaching freezing. Even if some
locations do not reach freezing, the ample moisture could at
least produce widespread frost which could be damaging to
sensitive vegetation. The Freeze Warning is in effect until 10
AM, at which point temperatures will begin to warm up.
Warmer and drier air will begin to push into the CWA Wednesday as
a ridge of high pressure sits over the Great Basin. 700 mb
temperatures will begin to climb into the upper single digits
with much drier air aloft. This will lead to a 10 to 15 degree
warm up on Wednesday, with highs returning to the 60s and 70s.
The dry air will also keep skies sunny with no chance of
precipitation during the day or Wednesday night. Cool and calm
conditions Wednesday night will lead to another chilly night for
areas west of the Laramie Range.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 104 PM MDT Tue Sep 23 2025
An upper level ridge will keep things rather dry
starting Thursday. Following the trough that pushed through the
Intermountain West, a amplified ridge sets in. The strong subsident
flow is expected to suppress any rising motion to decrease any
rain/snowfall chances. 700mb temperatures look to remain stagnant
between 9 to 11C Thursday through the weekend. So temperatures look
to remain the the 70`s in Wyoming with low to mid 80`s in the
Nebraska Panhandle. Friday into Saturday, an upper level trough
traverses across the Canadian Providences as well and another trough
pushing into the southern California coast. The southern trough will
inject some moisture into the region however will strengthen the
ridge over the intermountain west as the Rex Block sets up. The
northern trough will compress the ridge to give us a dry but gusty
weekend. Our next precipitation chances after the weekend may come
Monday afternoon with another shortwave pushing through the
intermountain west.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1133 AM MDT Tue Sep 23 2025
Ceilings look to bounce between LIFR and MVFR as the system
slowly pushes south. For KCDR and KAIA ceilings will bounce
between MVFR and VFR as the skies start to clear first then onto
KBFF. By 00z all sites should be hovering between MVFR and VFR
with the rain tapering off and by 06z all sites should be VFR.
Intermittent rainy conditions are expected through the evening
for most sites. Winds looks to be gusty with the rain showers
but gusts dont look to exceed 30 knots.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Freeze Warning from 2 AM to 10 AM MDT Wednesday for WYZ105-
     109>111-113-115.
     Winter Weather Advisory until 6 PM MDT this evening for WYZ114.
NE...None.
&&
$$
SHORT TERM...SF
LONG TERM...MM
AVIATION...MM

NWS CYS Office Area Forecast Discussion