988
FXUS65 KCYS 261103
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
503 AM MDT Sat Jul 26 2025

.KEY MESSAGES...

- There is a Marginal Risk (Level 1 of 5) for severe weather
  across the western Nebraska Panhandle.

- A Red Flag Warning has been issued for portions of southeast
  Wyoming for this afternoon and evening. Critical fire weather
  conditions possible again on Sunday.

- Warm and dry conditions continue Sunday and Monday, though a
  strong cold front will push through the region Tuesday,
  cooling temperatures significantly.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 250 AM MDT Sat Jul 26 2025

Quiet weather overnight tonight with just a few high level clouds
drifting across portions of the CWA. Clear skies will continue
through the early and late morning hours before more clouds move
into the region. Temperatures tonight are quite mild, in the 50s and
60s at most locations. Wheatland is the warm spot tonight at 73F as
of 08Z. Light winds are ongoing and will continue into the late
morning hours before increasing this afternoon.

Southwesterly flow aloft will lead to yet another active day across
southeast Wyoming and western Nebraska, though the best chances will
be in western Nebraska where SPC has indicated a Marginal Risk
(Level 1 of 5) for severe weather this afternoon. Multiple 500mb
vorticity maxima will eject out from an upper-level shortwave over
the western CONUS leading synoptic lift across the region this
afternoon. 700mb winds from the southwest will enable orographic
lift across the Laramie Range this afternoon, leading to some modest
convective initiation between 1 and 2 pm this afternoon. Surface
flow east of the Laramie Range will be southerly to southeasterly,
advecting in additional moisture into the region. Precipitable water
values will surge into the 0.9 to 1.0 inch range across the
Panhandle this afternoon, leading to ample moisture with any storms
that develop. Forecast soundings from the NAM and RAP do suggest
very dry low-level with a clear Inverted-V signature across the
Panhandle. Therefore, gusty winds look to be the primary threat
across the Panhandle this afternoon. Hail threat appears minimal due
to the very moist mid- and upper-levels thanks to monsoonal moisture
in the region. Very moist soundings and high PW values favor heavy
rain, but with the dry low-level some of this may evaporate leading
to strong microbursts. However, if the rain is heavy enough to
resist some of the evaporation from dry low-levels, wet microbursts
are not completely out of the question. 0-6km Bulk Shear will once
again be fairly weak across the region. Combined with moist
soundings, slow storm motion and fairly straight hodograph heavy
rains and flooding will be possible across portions of the Panhandle
that have seen a lot of precipitation in the past week. Despite
this, temperatures east of the Laramie Range will rise into the mid-
80s to low-100s.

West of the Laramie Range has the complete opposite situation today.
Strong westerly winds at 700mb and the surface will aide in drying
conditions across western portions of the CWA. With minimal
precipitation chances, it will be quite dry and windy across western
portions. Downward omega fields in the GFS suggest that further
drying from subsidence will occur this afternoon and persist through
the evening hours. Relative humidity values will drop into the 10 to
15% range this afternoon with winds gusting upwards of 30mph.
Therefore, the Fire Weather Watch has been upgraded to a Red Flag
Warning and expanded to include the Saratoga Valley and the
Arlington fire weather zones.

Sunday looks fairly dry across the region as an upper-level ridge
begins to more strongly influence the region. Southwesterly flow
aloft will remain, though subsidence will increase at the ridge
wobbles westward and strengthens over the southeastern CONUS. This
movement westward will cut off some of the additional moisture the
region has been seeing, with dewpoints dropping back into the 20s
and 30s across the region. Winds will remain fairly gusty due to
stronger 700mb winds and increasing surface pressure gradients.
Therefore, Sunday looks to hold another fire weather concern and
fire weather headlines will likely be needed. To avoid confusion,
decided to not issue a Fire Weather Watch for portions of the region
on Sunday as there is already a fire weather headline out for
southeast Wyoming. 700mb temperatures increase back into the 15 to
18C range Sunday afternoon, leading to very warm temperatures at the
surface. High east of the Laramie Range will be in the 90s to 100s
with high west of the Laramie Range in the mid-80s to low-90s. With
low dewpoints and gusty winds, it will feel slightly cooler than the
actual temperature. However, a dry heat is better than a wet heat.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 250 AM MDT Sat Jul 26 2025

Hot and dry conditions will continue Monday with only isolated
chances for precipitation across the western Panhandle. Temperatures
will be quite warm in the 90s to low-100s for much of the ahead as
700mb temperatures in the 15C range. Luckily, a potent cold front is
progged to move across the region Tuesday night into the day
Wednesday. This front will likely lead to a chance for strong
thunderstorms given the strength of the front. However, severe
chances will be hashed out in the coming forecast packages as
details are still difficult to ascertain. Luckily, this strong cold
front will lead to a significant heat relief as it drops
temperatures into the 70s and 80s for Wednesday onwards. In addition
to this, Tuesday will boast the best chances for widespread
precipitation as the front moves through. Temperatures will remain
cooler throughout the week before a warming trend starts again for
the weekend. For more details, see previous discussion below...

An upper level ridge will pull in warm but dry air into the
Intermountain west Sunday to keep us dry but brings along some Fire
weather concerns. NAEFS has PWAT values in the 10th and lower
percentile for SUnday and Monday to reinforce the fire weather
concerns. Winds look also to be a little breezy to put some areas
into the critical fire weather category so a Red flag may be
warranted especially for area west of the Laramie range. While the
RH values look to be under 15 percent across the forecast area the
fuels may not be cured enough to warrant a red flag warning.
Tuesday, a cold front looks to push through and provide us with our
next precipitation chances in the long term. Looking at the 700mb RH
field there looks to be a little bit of moisture associated with
this front to be utilized in afternoon convection. Wednesday, an
upper level trough moves across the Canadian Providences flattening
our upper level ridge even more than Tuesday. The synoptic ascent
combined with the continued moisture advection should continue our
precipitation chances into Wednesday night. This should also result
in cooler temperatures for the rest of the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 500 AM MDT Sat Jul 26 2025

Mostly clear skies early this morning with only a few patchy,
upper-level clouds drifting overhead. Winds are mostly calm this
morning across the terminals. Some smoke and haze from wildfires
may drift across the region this morning/early afternoon. No
visibility reductions are expected at this time, but this may
change as the smoke moves into the terminals. Winds increase
this afternoon and drive away and residual smoke. Primary
aviation concern today will be isolated to scattered showers and
storms across the Nebraska Panhandle with isolated showers
possible across southeast Wyoming. Very gusty conditions
expected at KRWL this afternoon, with gusts approaching 30kts.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from noon today to 8 PM MDT this evening for
     WYZ421>423-425-427.
NE...None.

&&

$$

SHORT TERM...AM
LONG TERM...MM/AM
AVIATION...AM