783
FXUS65 KCYS 040509
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1109 PM MDT Sun Aug 3 2025

.KEY MESSAGES...

- There is a Marginal Risk (Level 1 of 5) for severe weather for
  Sunday and Monday across portions of Southeast Wyoming and the
  Nebraska Panhandle, with gusty winds and hail the primary
  hazards.

- Critical fire weather conditions are expected beginning on
  Monday and continuing through the course of the week across
  Carbon and Albany Counties with very low afternoon RH values,
  poor overnight recoveries, and gusty winds.

- Gradual warming trend will bring potential triple digit heat
  by the middle of the week.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 200 PM MDT Sun Aug 3 2025

A weaker storm day is expected today as instability remains
limited across the region based on mesoanalysis (around 500-1500
J/kg), with almost nil wind shear, and limited forcing. Still, a
few echoes are showing up including one stronger storm as of
this writing in Sioux County, and the risk for some hail or
gusty winds through this evening can`t be ruled out. Inverted V
soundings would also support drier, gusty showers/storms further
west. Storms should weaken as diurnal heating wanes, with
clearing through the nighttime hours expected.

Tomorrow a similar setup is expected, but models aren`t nearly
as keen on development as today, with most CAMs only indicating
an isolated storm or two possible in the Nebraska Panhandle.
Once again dry surface levels will also contribute to the
potential for showers or storms being quite gusty as well.

But on the note of dry conditions, concerns are continuing to
rise for a problematic fire weather week for our western zones
where fuels are currently critically receptive to fire starts.
Daytime relative humidities into the single digits alongside
gusty winds as an upper level westerly flow pattern starts to
set in paired with poor overnight recoveries will bring a
hazardous setup that favors rapid fire spreads across Carbon and
Albany Counties. A Red Flag Warning has been issued for several
zones today, with a fire weather watch out for other zones
starting Tuesday and both continuing through the entirety of the
week. See the long term discussion for information on the
duration of this event as well as some recovery finally expected
by the end of the forecast period.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 200 PM MDT Sun Aug 3 2025

Storm chances are expected to drop off Tuesday as an upper-level
ridge builds over the southwestern CONUS and subsidence returns to
southeast Wyoming and western Nebraska. PWATs are expected to be in
the 10th percentile and gusty returning to the region to bring some
Fire Weather concerns Tuesday. This high is expected to remain
firmly in place, leading to more zonal flow across the region
throughout the week. With the ridge so close by, its influence will
be felt as temperatures once again rise into the 90s to near 100s.
The warmest day looks to be Thursday at this time, though Wednesday
through Friday will be quite hot. RH recovery looks to be minimal
until Friday prompting a Red Flag Warning west of the Laramie Range
for the long term forecast period. Winds look to meet criteria as a
low level jet forms to influence the winds for the remainder of the
week. On Thursday, an upper level trough will dive south from the
Canadian providences in the early evening into the overnight period.
Cluster analysis shows some uncertainty with how far south this
trough is able to dive slightly flattening our ridge possibly
reducing temperatures for Friday. There looks to be some moisture
with this trough aiding in RH recovery Friday night and into the
weekend. This trough may give some storm chances Friday afternoon
east of the Laramie range. However details are subject to change due
to how far south that trough dives and flattens our ridge a little
bit.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1108 PM MDT Sun Aug 3 2025

Mostly quiet tonight across the region as skies continue to
clear overnight. Light and variable winds are expected at most
terminals. KSNY and KAIA may see some lower clouds moving in
briefly overnight into the early morning hours, but confidence
is low at this time. Included TEMPO groups to showcase this
threat. Winds pick up in the afternoon, especially across
western Nebraska, with wind gusts up to 30kts.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Fire Weather Watch from Tuesday afternoon through Friday
     afternoon for WYZ420-421-427>429.
     Red Flag Warning from noon Monday to 6 PM MDT Friday for
     WYZ422>426.
NE...None.

&&

$$

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