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105
FXUS65 KCYS 122344
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
544 PM MDT Sat Jul 12 2025

.KEY MESSAGES...

- Temperatures will be warming Sunday through Monday, before a
  potent cold front brings cooler temperatures for Tuesday and
  Wednesday, with another warming trend for Thursday and Friday.
  Shower and thunderstorm chances will be greatest for Tuesday
  and Wednesday.

- Elevated fire weather conditions expected late this weekend
  and early next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
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Issued at 224 PM MDT Sat Jul 12 2025

There is an upper level ridge pushing into the Intermountain West
placing us in Northwest flow. Looking at water vapor imagery there
is some moisture advecting in from the Pacific Northwest that could
provide enough moisture for some shower possibly storm development
later on this evening. Models are holding onto 1000 joules of CAPE
along the I-80 corridor with only a couple hundred joules elsewhere.
There is still lingering low stratus along the I-80 corridor keeping
temperatures cool and stable. There`s also a very weak shortwave
passing through later this evening which looks like the primary
forcing for any storm development. However, with this low stratus
its uncertain if we will reach convective temperature to spark
initiation this afternoon. Also, with the timing of this shortwave it
may pass through a little late for storm development as we become
more stable with this nocturnal inversion. Slight chance for
thunderstorms was kept in case we hit convective temperature with
our 1000 joules of CAPE but its more likely that we remain
relatively dry today into tonight.

Sunday, there could be some fog development as this nocturnal
inversion sets up over the low level moisture. The upper level ridge
should stabilize our region of the Intermountain West as the
subsident flow may inhibit any convection. Sunday afternoon the
winds will switch to easterly upslope flow. THis upslope flow may
produce some showers in the mountains and morning foggy mess Monday
morning for the Summit and Foothills along the mountains if showers
do develop. Otherwise temperatures should return to warmer
temperatures as the 700mb temperatures reach between 17 to 20
celsius tomorrow. With these warmer temperatures there are some
elevated fire concerns mainly for Carbon County as RH values
drop into the low teens, however winds gusting over 25 mph will
be harder to do under the ridge.
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&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 224 PM MDT Sat Jul 12 2025

The long term will fluctuate between warmth and cooler
temperatures thanks to a mid-week system. Monday begins as the
warmest day of the period, with highs in the upper 80`s to upper
90`s with some locations across the Nebraska Panhandle eclipsing
100 for the day. A shortwave will be making its way across the
region though helping to disrupt the deep high across the
southwestern US and with it moisture will return as well. This
will start to fuel chances for scattered showers and
thunderstorms, but precipitation looks to be mostly sub-severe
at this time. That being said, daytime warmth alongside low RH
values and breezy winds could bring elevated fire weather
concerns for our western and northern zones where fuels have
reached critical status. Tuesday a cold front begins to move
into the region bringing a more widespread shower and
thunderstorm risk alongside cooler temperatures aided by cloud
cover. Storms could see a bit more severe risk compared to
Monday under more favorable conditions. Wednesday the front
should fully pass through the region with highs back down into
the 70`s to mid 80`s. Storms could once again initiate thanks to
this slow moving feature however, so anticipate another round
of potential precipitation. Thursday features temperatures
similar to Wednesday, but ridging will start to take back
control, and by Friday warming begins anew with 80`s to 90`s
once again in the forecast. Precipitation chances linger on both
days however as moisture remains and a shortwave on Friday
could fuel some stronger activity yet again.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
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Issued at 543 PM MDT Sat Jul 12 2025

A shortwave will move some high clouds into the area this evening
and overnight. Clouds will not pose any issues, with conditions
remaining VFR through the TAF period. Expect light and variable
winds overnight.
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&&

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

&&

$$

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