Cheyenne, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

410
FXUS65 KCYS 292335
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
535 PM MDT Mon Jun 29 2026

.KEY MESSAGES...

- Strong winds early this afternoon will gradually weaken this
  afternoon and evening.

- Elevated fire weather conditions will continue for much of
  the week ahead.

- Scattered thunderstorms late Tuesday evening will have the
  potential to become strong to severe, mainly in the central
  and southern Nebraska panhandle.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 303 PM MDT Mon Jun 29 2026

The unseasonably strong upper level low to our north continues to
drive active weather across our area today. The axis of the main
trough is currently on its way through the area. South to southwest
flow remains out ahead of the frontal boundary, while westerly flow
prevails behind. A plume of very dry air is being pulled across our
area underneath the upper level low. All together, this is
supporting an out-of-season high wind event and continuing fire
weather concerns across the area. Winds are exceeding expectations
in southeast Wyoming this afternoon. Widespread gusts over 60 mph
are occurring in Platte county. The highest measured gusts was 79
mph around 1:30PM between Wheatland and Glendo. Winds are rapidly
surging upward behind the slow moving frontal boundary progressing
from west to east this afternoon, but the window for high winds is
fairly short. Low-level height gradients are tightest right along
the trough axis, which is just moving east of the I-25 corridor at
the time of this writing. Therefore, we probably have another 1-2
hours of this before winds start to gradually come down through the
evening hours. While relative humidity isn`t really critical across
most of the area, the fairly extreme winds (for this time of year)
will lead to control issues. The Red Flag Warning remains in effect
until 9PM for the High Plains.

While high winds will be gone by the evening, we will remain breezy
for much of the night tonight as winds slowly come down. As the main
parent trough lifts off to the northeast, we will see weak ridging
try to nudge into our area Tuesday. Expect temperatures to be about
5 to 10F warmer than today, but fortunately, weaker gradients will
mean weaker winds. Still, breezy westerlies will remain over the US-
20 corridor and northward Tuesday. Therefore, these areas were added
into another Fire Weather Watch for Tuesday afternoon. As the ridge
lifts northward, expect southerly winds to follow, spreading into
the High Plains from south to north through the day. Confidence is
lower in these winds being consistent and strong enough to classify
as critical fire weather conditions. Later shifts will need to take
another look at this for a possible expansion of fire weather
headlines. South to southeast flow will eventually improve low-level
moisture, but this may not occur until later in the evening.
Meanwhile, another weaker upper level shortwave will approach the
area in the southwest flow aloft. In a fairly similar setup (but
overall weaker magnitude) to last night, we can expect to find
another lee cyclone developing over northeast Colorado and ejecting
northeastward Tuesday evening. Elevated instability will improve
through the evening hours in place with another round of potent
isentropic lift ahead of the approaching system. Expect some shower
activity to kick up late Tuesday afternoon likely in southeast
Wyoming or the central/southern Nebraska panhandle. As elevated
instability increases, the probability for lightning will also
increase, along with the potential for hail. The primary window for
storms looks to be between about 8PM and 2AM. Hail (some of which
could be large to very large) will be the primary concern, though
locally heavy rainfall due to training thunderstorms will be
possible too.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 303 PM MDT Mon Jun 29 2026

As we progress past Tuesday, we become stuck in Southwest flow
on the front side of this ridge. The warm, dry, but smokey air
from the Desert southwest and the Colorado/Utah fires will be
filtering over the area for the remainder of the week. This will
limit our rain chances as this dry air removes all the moisture
from the surface and lower dewpoints and RH values. The models
have a few shortwaves pushing into the region past Tuesday but
with no moisture and very limited forcing there isn`t much
confidence these waves will do anything beside increase our
gradient and produce the normal amount of wind through our area.
Fire weather will be the biggest concern as our fuels will
enter a curing state once again despite our stormy 7 days last
week. Winds will be light to marginal so it may be difficult to
reach Red Flag criteria for most of our area despite the low RH
and curing fuels. There is another trough that may move through
Friday night into Saturday morning for a possibly wet start to
our 4th of July weekend plans. Looking at the global models,
each one has a different intensity of forcing but there is a
general uptick by the models compared to yesterday. While it
still doesn`t look to be a strong four corner low, the shortwave
trough may be strong enough to overcome the dry air and give us
some measurable precipitation. Given it is the 4th of July, we
will be monitoring this set up closely and try to narrow down
timing and locations for everyone.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 535 PM MDT Mon Jun 29 2026

VFR conditions will dominate across all terminals for the duration
of this TAF period. Gusty westerly winds up to 45 knots will ease
over the next hour or so and become generally less than 6 knots by
06Z this evening. However, this is short-lived as winds will ramp
right back up Tuesday to around 25 knots, by 19Z for the Wyoming
terminals and by 22Z for the Nebraska sites.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning until 9 PM MDT this evening for WYZ417>419-
     430>433.
     Fire Weather Watch from Tuesday morning through Tuesday
     evening for WYZ417-418.
     High Wind Warning until 6 PM MDT this evening for WYZ106-107-
     110.
     High Wind Watch until 6 PM MDT this evening for WYZ116.
NE...Red Flag Warning until 9 PM MDT this evening for NEZ434>437.
     Fire Weather Watch from Tuesday morning through Tuesday
     evening for NEZ434.

&&

$$

SHORT TERM...MN
LONG TERM...MM
AVIATION...RZ