738
FXUS65 KCYS 210524
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1124 PM MDT Mon Jul 20 2026

.KEY MESSAGES...

-Hot, dry, and breezy conditions continue today.

-Numerous to widespread beneficial showers and scattered
thunderstorms will occur Wednesday and Thursday afternoons and
evenings, with lesser coverage of late day shower and thunderstorm
coverage for Friday through the weekend and into early next week.

-Maximum temperatures will be moderated by clouds and precipitation
coverage for Wednesday and Thursday, then hot temperatures will
return for Friday through Monday due to lesser coverage of late day
showers and thunderstorms and cloud cover.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 1229 PM MDT Mon Jul 20 2026

The hottest day of the year is underway today across much of
southeast Wyoming and western Nebraska. Highs in the mid 90s are
expected for location such as Cheyenne and Rawlins with triple-
digit heat throughout all of the NE panhandle and east- central
Wyoming including Torrington and Douglas. This upward tick in
temperatures today is a result of slightly more subsident flow
coming off the higher terrain to the west. Heat Advisories
remain in effect until 6pm tonight for east-central Wyoming as
well as most of the Nebraska Panhandle.

The high plains region remains on the eastern periphery of a
broad monsoonal ridge, however PWAT values have inched up ever
so slightly today given the aforementioned light westerly flow.
As a result, isolated showers and thunderstorms will once again
move off the higher terrain of the Snowy, Sierra Madre, and
Laramie ranges and drift in a southeasterly direction. Extremely
dry speckled layers with nearly 50-degree surface dewpoint
depressions will limit any precipitation amounts to only a few
hundredths to perhaps a tenth of an inch underneath storm cores
today. Overnight, expect partly cloudy skies and above-normal
temperatures.

Temperatures will drop back slightly on Tuesday as heights lower
and monsoon moisture increases from the west. Expect an uptick
in thunderstorm coverage in the higher terrain, possibly
spreading a bit farther east into Cheyenne and the high plains
after around 21z. However, higher PWAT values still remain a bit
too far off to the west of southeast Wyoming to significantly
impact the forecast. By Tuesday night, this monsoonal plume will
better position itself over our region, resulting in some
overnight weak convection as a weak area of lift impinges on the
high plains from the north. Forecast confidence remains medium
throughout the short-term due to the unpredictable nature of the
exact location of thunderstorms. High confidence persists for
the very warm temperature forecast today.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 1229 PM MDT Mon Jul 20 2026

Wednesday...Beneficial rains will become more widespread in areal
coverage with s decent increase in low level dewpoints and mid level
monsoonal moisture and upslope mechanical southeast winds advecting
low level moisture into our counties. Will see scattered to numerous
afternoon and evening shower and thunderstorm coverage, most
prevalent along the I-25 corridor where lift and orographic lift
will be maximized corresponding to the deepest moisture supply. The
most widespread coverage of showers and thunderstorms will lie along
the 850/700 mb theta-e ridge axis from Douglas to Laramie to
Cheyenne.

Thursday...More beneficial rains are anticipated as a decent
positively tilted shortwave trough aloft passes overhead near peak
heating, and with beaucoup...plenty of low and mid level moisture
and decent upslope southeast winds advecting low level moisture
northwestward, expect to see numerous to widespread showers with
scattered thunderstorms in the afternoon and evening, focused once
again along the I-25 corridor and near the mountains where
orographics will coincide with the best 850/700 mb theta-e ridge
axis.

Friday...Drier air at low and mid levels advects into our counties
as the dominant ridge over Colorado and southern Wyoming reasserts
itself. Thus dry and hotter.

Saturday through Monday...Isolated to scattered afternoon and
evening thunderstorms expected, with areal coverage increasing each
day due to increased mid level moisture. Fortunately, more
beneficial rains expected concentrated south of a Rawlins to
Scottsbluff line and over and near the Snowy, Sierra Madre and
Laramie Ranges. Typical weak northwest flow aloft on the northeast
periphery of the ridge aloft will aid in occasional passing
shortwave troughs aloft near peak heating.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1115 PM MDT Mon Jul 20 2026

Continued scattered shower activity is evident on regional
radars. This activity is not widespread enough to warrant
including as a group in TAFs and is expected to diminish as the
night progresses. Winds are variable and light at most
terminals, but KLAR and KSNY are gusting to 25 knots out of the
east. No MVFR CIGs are expected through tomorrow afternoon. In
the early afternoon hours showers and thunderstorms are expected
to start near KRWL and spread in coverage eastward through the
afternoon and evening. Based on current trends and confidence in
coverage in model guidance, prob30 group were added/kept to
southeast Wyoming terminals. These cover tomorrow afternoon
through the end of the forecast period. Some of these storms
could produce strong winds to 45 knots or greater, lightning,
and heavy rain at terminals. Outside convection the prevailing
winds are out of the southeast between 10 to 20 knots.

&&

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

&&

$$

SHORT TERM...MAC
LONG TERM...RUBIN
AVIATION...RV