257
FXUS65 KCYS 141148
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
548 AM MDT Mon Sep 14 2026

.KEY MESSAGES...

- Critical fire weather conditions expected today alongside the
  potential for high winds.

- Much cooler on Tuesday with temperatures a few degrees warmer
  through the end of next week and daily chances of showers and
  thunderstorms.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 230 AM MDT Mon Sep 14 2026

Widspread lingering showers and thunderstorms across the region
will continue to progress out of our area through the morning
hours. Behind this activity as a cold front moves into our
region and aloft a deep low spins across to our north with
attendant troughing moving across the region, drier air will
filter in behind it with PWAT values plummeting from around 1
inch to under or around a quarter. Meanwhile surface pressure
gradients will remain enhanced, with Craig to Casper gradients
around 50-55 meters at 850mb, and a low-level jet at up to 50
knots at 700mb. This will promote two potential threats for the
day, the first of which will be possible strong to high winds.
For now, have kept the High Wind Watch in effect and not
upgraded because in-house guidance is still around or under a
40% probability our wind prone locations will see high winds,
and most of the above guidance is just below what we would like
to see for a Warning. Still, winds 50-55 mph are likely, and it
wouldn`t be surprising if a site or two reached 58+ today.
Secondly, the dry air plus strong winds will promote a Critical
Fire Weather environment, with Red Flag Warnings out across
Southeast Wyoming and now into the Nebraska Panhandle.
Otherwise, look for temperatures west of the Laramie Range to be
quite cool as this area will remain behind the front, with 60`s
to 70`s for the day. But to the east, it`ll be another warm one
with 70`s to 80`s.

This will change on Tuesday however as all zones will be behind
the front. Highs for the day will only peak in the 60`s to 70`s
giving a nice shot of fall air. Breezy winds from enhanced
pressure gradients will remain, but not nearly as strong as
today, and showers and thunderstorms should return alongside
moisture, but strong to severe activity will be unlikely.
Wednesday ridging builds back in and temperatures should warm
back up, with highs in the 70`s to 80`s for the day. Similarly
to Tuesday, another round of afternoon showers and thunderstorms
is expected, but also similarly a lack of strong severe
parameters will keep this activity sub-severe for the day.
Pressure gradients will be relaxing as well, and gusty winds
should finally subside for now.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Issued at 240 PM MDT Sun Sep 13 2026

Tuesday and into the weekend, the upper level low
keeps migrating east into the Great Lakes and Hudson Bay region. The
counter clockwise circulation will begin filtering cold air from the
Arctic into the region undergoing some warming/modification as it
pushes south over us. 700mb temperatures will drop between 8 and 12C
translating daily surface temperatures into the cooler 60`s and
70`s and overnight temperatures into the 40`s and 50`s. Daily
rainfall chances start to occur Wednesday as a train of Low
pressure system system are expected to travel through the
Pacific Northwest over the next 7 days. This precession of low
pressure systems will push the ridge eastward into the central
and southern plains leaving the intermountain west susceptible
to multiple accompanied shortwaves but ahead and following each
progged low pressure system.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 544 AM MDT Mon Sep 14 2026

Lingering showers, storms, and low clouds will continue to
promote a mixture of all flight categories for all sites except
for KRWL/KLAR over the next few hours. But these should be
clearing and lifting as stronger winds from the SW to W move
across the region and continue to turn more NW`ly into the later
hours before becoming N`ly to NE`ly overnight. Widespread gusts
of 20-35 knots expected, but locally stronger gusts of 40+ knots
possible, primarily impacting KRWL for the highest speeds. While
winds should weaken into the evening hours, some stronger speeds
10-20 knots could impact KCYS/KSNY/KAIA overnight. CIGs will
lift through the day and clear, with mid to high level clouds or
SKC by tonight.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from noon today to 8 PM MDT this evening for
     WYZ417>423-427-432-433.
     High Wind Warning until 6 PM MDT this evening for WYZ110.
NE...Red Flag Warning from noon today to 8 PM MDT this evening for
     NEZ434>436.

&&

$$

SHORT TERM...CG
LONG TERM...MM
AVIATION...CG