Carpenter, Wyoming Weather Forecast Discussion

713
FXUS65 KCYS 102317
AFDCYS
Area Forecast Discussion
National Weather Service Cheyenne WY
517 PM MDT Wed Sep 10 2025
.KEY MESSAGES...
- Daily chances for afternoon showers and thunderstorms continue
  through Friday with gusty winds, downpours, and isolated hail
  possible.
- A cold front will impact the area later this week bringing
  cooler temperatures through the weekend.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 330 PM MDT Wed Sep 10 2025
Current KCYS radar loop shows some widely scattered showers and
a few embedded thunderstorms across eastern Wyoming this
afternoon. Convection looked a little more impressive when it
developed further west late in the morning/earlier in the
afternoon, but has since moved over a region of increasing
boundary layer CIN. Expect this to continue into the evening
hours with a slight erosion of BL CIN across the
Wyoming/Nebraska border. Model soundings continue to show a
marginal environment for strong to severe thunderstorms, mainly
along and east of the Laramie Range this afternoon due to SBCAPE
of 1000 to 1500 j/kg. However, the best shear (>30kt) is located
in the area with the highest CIN. Can`t rule out a few stronger
storms producing near quarter sized hail and wind gusts around
50 to 60 mph for the rest of this afternoon and into this
evening.
Not as cool tonight with intervals of mid to high level
cloudiness and some fog/low clouds possible. Low temperatures
will generally be in the 50s to near 60, with a few mid to upper
40s across the high valleys west of the Laramie Range. Added
patchy fog to portions of the NE panhandle with short range
ensembles showing probabilities over 30%. Think coverage should
be pretty limited due to midlevel cloudiness.
Models show similar weather on Thursday with a continuation of
southwest flow aloft. There will be some boundary layer CIN over
far eastern Wyoming and western Nebraska, but do not expect the
cap to be as strong as today. Convective parameters do not look
quite as impressive at first glance, with CAPE values around
1000 j/kg over the eastern plains. 0-6 km shear looks a little
more favorable for strong to severe thunderstorms even though
dew points and boundary layer moisture aren`t nearly as
impressive. Models do show some jet energy aloft and some upper
level diffluence centered over far southeast Wyoming and
western Nebraska late Thursday afternoon. Latest runs of the
high res CAMs indicate widely scattered multicells eventually
becoming more linear as they push northeast. Agree with SPC`s
marginal risk for wind gusts over 50+ mph and hail up to quarter
size. One last above normal day for temperatures before the
next cold front moves into the region with highs in the upper
70s to upper 80s...warmest below 4500 feet. Kept POP between 15
to 30 percent for widely scattered thunderstorms, and closer to
50 percent for the mountains.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 140 PM MDT Wed Sep 10 2025
Friday is expected to be the warmest day of the long term as
high pressure ridging begins to shift eastwards, but the region
remains under a warm southwesterly flow as a deep trough begins
approaching our area. This system will move across and continue
eastwards through the weekend. This should allow for two fairly
similar days over the weekend, with cooler temperatures and
highs in the 70`s mostly, though some high 60`s may be possible
further west, while to the east in the Nebraska Panhandle highs
will peak in the low 80`s. A transitory ridge then helps to
warm us back up for the first couple of days next week, with
70`s to 80`s returning to the CWA before another upper level low
is expected to bring a return to cooler conditions by the
middle of next week. With this initial system we should see
precipitation to end the week and begin the weekend, with
widespread rain and thunder through Saturday. Moisture won`t be
extremely high, with PWAT values only around 125-150% of normal
according to ensembles, which is still under an inch for our
CWA. This leads to QPF of around or under a quarter of an inch
for Friday and Saturday, hardly a widespread soaker as we see
the best fetch of moisture kept off to our northeast. Still
anything helps, and a few locations may see locally heavier
amounts depending on the strength of thunderstorms in the
region. Sunday and Monday are expected to be dry with the
transient ridge moving in, but we`ll see moisture return on
Tuesday alongside precipitation chances once again. Overall
there is only moderate confidence (50%) in the forecast, with
ensemble clusters finding less agreement on the aforementioned
features and their placement and strength.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 515 PM MDT Wed Sep 10 2025
Isolated storms are ongoing across the region, with a strong
thunderstorm approaching KBFF. This storm looks to hang around
the KBFF terminal for a while, so kept -TSRA as prevailing.
Storms will continue to be in the vicinity of other terminals
and occasionally impacting the terminals. Thunderstorms will
come to an end in the next 2 to 4 hours, with isolated showers
continuing behind the storms. Gusty winds are ongoing at all
Nebraska terminals and will continue through the evening into
the overnight hours.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...TJT
LONG TERM...CG
AVIATION...AM

NWS CYS Office Area Forecast Discussion