279
FXUS65 KCYS 072347
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
545 PM MDT Sat Jun 7 2025

.KEY MESSAGES...

- A back door cold front Saturday night will bring scattered
  showers and thunderstorms to our northern zones late Saturday
  night/Sunday morning, followed by another round Sunday PM near
  the WY higher terrain.

- Mostly dry and mild weather will prevail for Monday and Tuesday,
  with increasing chances for late day showers and
  thunderstorms for Wednesday through Friday.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 140 PM MDT Sat Jun 7 2025

Mostly dry and fair conditions this afternoon after our wet and
active week, with mostly clear skies and some breezy winds due
to an enhanced pressure gradient. As we move into the evening, a
backdoor cold front is expected to drop down from the north with
scattered showers and possibly isolated thunderstorms expected
for our northern zones. Unfortunately, this system is also
expected to bring Canadian wildfire smoke. High res guidance
indicates we should see some hazy conditions and will impact our
northern and eastern zones through Sunday, and could make it
down as far as Cheyenne itself, but will be likely along the
borders of Wyoming and South Dakota as well as all along the
Nebraska Panhandle.

Moving into Sunday itself, an influx of moisture and flow back
towards the high terrain will promote scattered shower and
thunderstorm development across our higher terrain of Wyoming
during the afternoon. Instability will be meager and shear
lacking, so most of this activity will likely be general thunder
with limited risk of stronger storms. That being said, inverted
V soundings do suggest we could see some stronger gusts from
any activity, so as usual be on the lookout for gusty outflows
from any showers or storms that do develop. Precipitation
activity should wane as daytime heating subsides. The cold
front plus precipitation should also cool us back down into the
60`s to 70`s for highs tomorrow, but expect this to be the
coolest day of the next week as high pressure ridging begins to
move in and bring us more summer-like warmth.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 140 PM MDT Sat Jun 7 2025

Monday, The upper level low that dropped down from Alberta
looks to push off to the east Monday morning into the afternoon.
Being on the west side of the low, the Intermountain west will
be in Northwest flow with some drier air filtering in. Our
region looks to remain dry and breezy through Tuesday afternoon.
Wednesday and Thursday are predominantly westerly flow but weak
shortwaves Look to provide enough forcing and lift to produce
some isolated to scattered storms and showers. Friday, An upper
level trough pushes through the Intermountain West. The models
anticipate a lee cyclone between Wyoming and Colorado which
creates enough lift and forcing for scattered thunderstorms by
which a vorticity gradient pushing through with 1200-2000 joules
of CAPE. So Friday will be worth monitoring for trends and see
how the Hi-res models resolve the trough when it comes into
their time span.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 545 PM MDT Sat Jun 7 2025

A back door cold front will quickly move south across the high
plains this evening. Increasing low to midlevel cloudiness is
expected with bands of rain showers after midnight across the
western Nebraska terminals.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail this evening
and tonight with winds shifting into the north behind the cold
front. MVFR conditions are possible after 08z for KCDR, KAIA, and
possibly KBFF, but confidence is pretty low at this time. Best
chance for afternoon showers and thunderstorms will be for
KLAR and KCYS, but timing is highly uncertain.

&&

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

&&

$$

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