078
FXUS65 KCYS 022104
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
304 PM MDT Tue Sep 2 2025

.KEY MESSAGES...

- Drier conditions expected through much of this week with a
  warming trend bringing near normal temperatures today through
  Thursday.

- A few isolated showers and thunderstorms possible this afternoon.
  Mainly near the mountains.

- Cooler temperatures and more unsettled Friday through next
  weekend as a Canadian cold front and a Pacific cold front
  impact the region.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 303 PM MDT Tue Sep 2 2025

Hi-res guidance continues to agree on some possible weak
thunderstorms in our mountainous areas along a convergence zone.
Given the HREF paints about 100-300 joules of CAPE for that area
with much of the models not deviating from the range, confidence is
higher that these will be weak showers/thunderstorms. Can`t rule out
some claps of thunder and very small hail but overall should be a
lackluster performance. The models also maintain a consensus that
these storms should be done by the late evening. Wednesday, The
upper level ridge over the Western United States wobbles a little
more east compressing the pressure gradient a little more placing us
in a north-northwest flow. Due to the deeper mixing and the jet
overhead tomorrow will be breezy east of the mountains or the I-25
corridor with the highest gusts produced will likely be in the
Panhandle. With this elevated Northerly flow, cool air will be
transported over the region giving us a morning crisp Autumn feel
Thursday morning. However, with the upper level ridge close by
temperature recovery throughout the day should be sufficient for
temperatures to climb back into the 70`s and 80`s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 303 PM MDT Tue Sep 2 2025

Analysis of the ensemble clusters show a bit more disagreement
today on the expected pattern over the long term, but overall
there is still at least moderate agreement leading to moderate
confidence on the forecast in the long term. Upper level ridging
will be shunted backwards by a very deep and powerful low and
trough over eastern Canada and the US on Thursday, with this
ridge expected to try and recover then going into the weekend,
but a weakening low (the expected remnants of Tropical Storm
Lorena) lifting up from Mexico will help to continue to weaken the
ridge (though remaining south of our region), with a Pacific
trough moving inland across the West Coast expected to be the
final nail in the coffin for this high pressure system moving
into next week. For our weather across the CWA, this means we`ll
see a bit more warmth on Thursday with widespread 80`s for
highs, followed by a Canadian cold front on Friday expected to
pull temperatures down by around 10 degrees with Cheyenne only
reaching 68 for a high according to the NBM, with temperatures a
bit more steady then over the weekend and into the beginning of
next week in the 70`s to low 80`s. Meanwhile the pressure
gradient on Thursday is expected to be stout, and with an upper
level jet max grazing the region, we`ll see a very gusty day
with gusts of 25-40 mph expected east of the Laramie Range.
Finally, precipitation chances don`t see a very noteworthy rise
until the weekend, but more widespread thunderstorms look
possible by then with Sunday looking to be the best day for more
widespread activity.


&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1155 AM MDT Tue Sep 2 2025

VFR conditions expected over the next 24 hours. Winds breezy
today with gusts in the 15-25 knot range expected. A few clouds
possible at mid levels around 8-10k feet, with a passing shower
over the mountains near KLAR. Winds lessen overnight but expect
another diurnal push with stronger gusts possible tomorrow into
the afternoon.

&&

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

&&

$$

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