660
FXUS65 KCYS 101718
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1118 AM MDT Thu Jul 10 2025

.KEY MESSAGES...

- There is a potential for isolated strong to severe storms on
  Thursday afternoon and evening for portions of the western
  Nebraska panhandle.

- Much cooler Thursday night and Friday as a strong cold front
  moves south across the high plains.

- Brief warming trend Sunday & Monday ahead of the next strong
  July cold front.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 305 AM MDT Thu Jul 10 2025

Pretty warm early this morning with thick mid to high cloud
cover pushing across the area and some downslope winds ahead of
the Pacific disturbance which is moving eastward along the
Colorado/Wyoming border. Temperatures at 2:30 am local time are
in the middle 70s to low 80s across the area along and east of
the Laramie Range. Further west, well-advertised light showers
and embedded thunder currently lifting northeast ahead of the
Pacific disturbance and weak midlevel cold pool. These showers
and thunderstorms are producing gusts over 50 mph over portions
of Carbon County early this morning. Gusts have been very brief,
so handling with convective Special Weather Statements for now.

Upper level ridge axis will continue to break down today as it
pushes eastward, allowing the Pacific disturbance to cross into
eastern Wyoming and western Nebraska by the afternoon. This
will aid in shower and thunderstorm development this afternoon
after a brief lull later this morning. As the trough axis and
midlevel cooler air moves over the area, instability will
increase with marginal 0-6km shear around 25 knots. Model
soundings and convective parameters do not look as impressive
compared to this time yesterday with SBCAPE values around 1000
to 1500 j/kg lower, likely due to the partly to mostly cloudy
skies today and the midlevel cold pool lagging a few hours
behind. There is decent forcing but 0-6km shear has remained
around the same. Agree with SPC, which has lowered the severe
threat to a marginal risk for the eastern plains today. High res
CAM guidance showers multicell clusters and occasional linear
bands developing after noon today and continuing through 700 pm
across the Nebraska Panhandle this evening. Thunderstorm
activity will linger through the evening hours as the trough
axis pushes east of the Nebraska/Wyoming border, but should end
before midnight. Gusty winds up to 65 mph and ~1.00 diameter
hail appear to be the high end threats with these storms today.
Slight cooler temperatures today across the area, but highs will
be around normal for this time of the year.

Once the shortwave trough axis moves east of the area by early
Friday, models show the upper level flow veering into the
northwest as a relatively strong cold front for this time of
year digs south into the Front Range. Expect much cooler
temperatures for Friday and Saturday, however...not as cool
as we were expecting a few days ago as the cooler air behind the
front is trending slower, and the forecast stratus deck looks
like it will be brief over southeast Wyoming. With ensemble
means and deterministic trending higher with high temps,
increases max temperatures on Friday a few degrees and generally
in the mid 70s to low 80s...warmest for far eastern Wyoming and
western Nebraska. Low stratus and potential fog looks like it
will be delayed until Friday night...for mainly the I-80 Summit
and vicinity as surface winds finally shift into the east and
then southeast. With more sunshine expected on Friday afternoon,
this also means a much better potential for showers and
numerous thunderstorms, especially for southeast Wyoming.
Increased POP up to 70 percent along and west of I-25. Will have
to watch for a better chance of severe weather, but agree with
SPC and the marginal risk for now.

Saturday will be similar to Friday but with a warming trend
beginning a day early north of Interstate 80. Further south,
clouds may hang on into the early afternoon hours with a better
chance for thunderstorms...generally from Elk Mountain eastward
to Sidney Nebraska.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Issued at 329 PM MDT Wed Jul 9 2025

For later this weekend, a gradual warming trend is expected as
the upper level high across the desert southwest slowly builds
northward and intensifies. Thunderstorm activity is forecast to
become more isolated through by late Saturday and Sunday as
700mb climb above 15c. Highs in the upper 80s to mid 90s will
return for much of the forecast area by Sunday and next Monday.

Models are still showing another potent upper low over southern
Canada dropping another strong cold front across the forecast area
on Monday. Timing of the front at this time looks to be in the
afternoon, so high temps will remain hot and thunderstorm chances
and intensity will depend on the midlevel cap. Expect cooler
temperatures in the post frontal environment for Tuesday along with
upslope stratus/fog in the early morning. Upslope forcing along with
cooler midlevel temps will keep chances for showers and
thunderstorms in place through Tuesday evening.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1118 AM MDT Thu Jul 10 2025

Primarily VFR will continue through the forecast period for
southeast Wyo and western Neb terminals. The main aviation
weather concerns are scattered rain showers and thunderstorms
through this evening, along with gusty north winds. Gusts 25+
kts are likely near and outside any shower activity in Wyo this
afternoon and everywhere tomorrow morning. Stronger gusts will
accompany any storm this evening. An overnight lull with a brief
transition to south/southeast flow may contribute to a limited stratus
deck and/or fog from KCYS to KLAR. Low confidence and coverage
has precluded any mention in the TAF for now.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...WFOCYS
AVIATION...DS