Severe Thunderstorm Warning 3, NWS Cheyenne, WY

Area Forecast Discussion
National Weather Service Cheyenne WY
208 PM MDT Sat May 9 2026

.KEY MESSAGES...

- Numerous rain showers and widely scattered thunderstorms
  expected on Saturday. A few strong thunderstorms or an
  isolated severe storm possible.

- Mostly dry and warmer weather will prevail for Sunday through
  Wednesday, with thunderstorms possibly returning late in the
  week.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 152 PM MDT Sat May 9 2026

Scattered showers and some weak thunderstorms are noted on radar
across the area as of this afternoon primarily for our northern
zones with much stronger activity seen to the northwest moving
into Central Wyoming. At the surface, a cold front is currently
draped across portion of the northern Nebraska Panhandle and up
into northeastern Wyoming, while aloft an upper level shortwave
is making its way across Wyoming and into Nebraska through the
day. Current expectation for the rest of today is in line with
the morning forecast package, and expecting scattered
thunderstorms with widely scattered strong to possibly severe
activity today.

High resolution guidance remains largely in agreement on this
continuing over the next several hours, with a few thunderstorms
possible but remaining largely sub-severe. Then as the front
drops across the area, we should see an uptick in thunderstorm
activity along this boundary across the I-25 and I-80 corridors,
with an increase in severe parameters fueling stronger to
possibly severe activity. Along this area should be increasing
CAPE values with pockets of 800-1200 J/kg, 0-6 KM shear values
of 40-60 knots but isolated peaking at around 70-80 knots noted
as well on the HRRR, and steepening low and mid level lapse
rates. Storms will likely be clustered in nature with limited
potential for individual supercells, though cannot rule out at
least one to occur early on. By the later part of this
timeframe, most CAMs agree that activity will congeal into more
linear fragments as they move into Nebraska with intensity
waning as the sun sets. Greatest threats will be gusty winds and
isolated large hail with activity being higher based in nature.

Overnight temperatures should actually chill notably behind the
cold front in tandem with clearing skies fueling radiational
cooling, with widespread lows in the 30's expected Sunday
morning. A building ridge will then control the weather across
the area for the remainder of the short term as we see
temperatures rebounding into the 60's and 70's on Sunday, and
then significant warmth on Monday as highs skyrocket into the
80's and 90's. This will be knocking on the door of record highs
for most of our forecast area with highs 20 degrees above
normal. Alongside this record warmth brings the return of
critical fire weather conditions as our RH values bottom out in
the low teens to near single digits on Monday with some breezy
winds possible along the I-25 corridor and along the base of the
Laramie Range. Will have to take a deeper dive into fire fuels
as we move into Sunday and determine if Red Flag products will
be necessary or not.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 152 PM MDT Sat May 9 2026

The general pattern going into Tuesday is one of upper level
ridging. A rather large high pressure system will be building over
the Four Corners Region with an axis of it passing through. This
should allow temperatures to reach the mid 70s to low 80s. We do
have fire weather conditions showing up in the interior mountains
near Rawlins this day. Humidities appear very low, possibly getting
into the low teens with gusty conditions. Elsewhere, dry conditions
may favor some elevated concerns. These conditons should persist
into Wednesday where some spots in valleys east of the Laramie Range
could reach the 90s and near daily record temperatures. Humidities
plummet given the favorable environment for deep layer mixing.
Relative humidities reaching the mid and low teens are a
possibility. Attention to conditions these few days should be
maintained for fire weather interests. Thursday a plume of monsoonal
like moisture makes its way north from the Eastern Pacific into our
area. The ridge gets pushed southeast into Texas allowing increasing
chance of isolated to scattered showers and storms. PoPs are low at
this time, and surface layer mixing will still be high creating dry
conditions at the surface. So, the most likely outcome Thursday are
the continued fire weather risk, but maybe throw in a few dry and
windy thunderstorms. About this time a compact, but high amplitude
trough will be passing over the northwestern Pacific Coast. Global
models differ on the speed and strength of this feature. The GFS is
much more aggressive with this trough and is a bit slower/south with
the progression as it reaches our area Friday. ECMWF is a bit more
progressive, weaker and northward with its trajectory. Both have the
general negative tilt form to the trough which tend to be more
dynamic than positive and flatter systems. The timing is somewhat
important from a severe weather angle, a slower and more southward
system may allow for the favorable left exit region of the jet to
the south of the trough to be in phase with the better daytime
heating. At the moment the models make this a more north and
eastward event. A dry slot on the south side of the system will
create sinking air and may tighten pressure gradients in the 700
mbar enough to create strong winds. Indeed our machine learning
models highlight an elevated risk Friday morning and afternoon
(~40%) for west to east mountain gap flow locations. Conditions area
wide continue to by dry and warm, so fire weather is likely to
continue, even going into Saturday. Fuels in our Nebraska Panhandle
zones are not in good shape with little green up reported. The
snowfall received on the eastern slopes and ridges of the Laramie
Range has caused some greenup with vegetation. The periods of recent
rain may stave off more critical fire concerns going into this
period.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1132 AM MDT Sat May 9 2026

Showers are developing across the Nebraska Panhandle and within
the vicinity of KCDR, KBFF, and KAIA. This activity is expected
to become more widespread before the arrival of a mid level
shortwave. Widespread showers and thunderstorms are expected to
form over the mountain ranges and spread southeast into the
high plains. Impacts to terminals may include variable surface
winds and gusts above 50 kts, hail, lightning, and reduced
visibilities down to two statue miles or less. KBFF, KAIA, and
KSNY have the highest confidence of thunderstorms this
afternoon. Storms are possible at all other terminals with the
same threats to aviation. A few hour lull in storms is expected
after sunset before more shower and storm development is
possible for the Nebraska Panhandle terminals. The intensity of
this convection is expected to be less than the afternoons,
however ceilings could be lower. Elsewhere, weak, variable winds
and high humidity may create fog near sunrise. Probabilities
are too uncertain at the moment and were left out of the TAFS
for this synoptic forecast period. Cloud coverage is expected to
diminish going into tomorrow afternoon.

&&

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

&&

SHORT TERM...CG
LONG TERM...RV
AVIATION...RV

Special Weather Statement
National Weather Service Cheyenne WY
226 PM MDT Sat May 9 2026

WYZ104-109-092115-
Central Carbon County WY-Ferris/Seminoe/Shirley Mountains WY-
226 PM MDT Sat May 9 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTH CENTRAL CARBON COUNTY
THROUGH 315 PM MDT...

At 226 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Split Rock to near Independence Rock.
Movement was southeast at 30 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Muddy Gap, Dome Rock, and Miracle Mile.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4243 10752 4244 10720 4243 10671 4226 10657
      4209 10737 4235 10753
TIME...MOT...LOC 2026Z 324DEG 26KT 4247 10749 4250 10719

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Natoli

Special Weather Statement
National Weather Service Cheyenne WY
319 PM MDT Sat May 9 2026

WYZ104-105-092215-
Shirley Basin WY-Ferris/Seminoe/Shirley Mountains WY-
319 PM MDT Sat May 9 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN CARBON AND
NORTHWESTERN ALBANY COUNTIES THROUGH 415 PM MDT...

At 319 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Dome Rock, or 37 miles southwest of Casper, moving
east at 40 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Dome Rock, Shirley Basin, and Prior Flat Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4243 10674 4243 10607 4205 10607 4230 10679
TIME...MOT...LOC 2119Z 289DEG 34KT 4235 10665

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Natoli

Special Weather Statement
National Weather Service Cheyenne WY
321 PM MDT Sat May 9 2026

WYZ104-105-109-110-092215-
Shirley Basin WY-North Snowy Range Foothills WY-
Central Carbon County WY-Ferris/Seminoe/Shirley Mountains WY-
321 PM MDT Sat May 9 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN CARBON COUNTY
THROUGH 415 PM MDT...

At 321 PM MDT, Doppler radar was tracking a strong thunderstorm near
Miracle Mile, or 33 miles northeast of Rawlins, moving southeast at
45 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Hanna, Seminoe Campground, Miracle Mile, Seminoe Dam, Kortes Dam,
Seminoe State Park, and Dome Rock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4223 10705 4234 10690 4207 10610 4180 10661
TIME...MOT...LOC 2121Z 302DEG 38KT 4222 10695

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Natoli

Special Weather Statement
National Weather Service Cheyenne WY
416 PM MDT Sat May 9 2026

NEZ020-054-WYZ118-119-092245-
Kimball NE-Banner NE-Central Laramie County WY-
East Laramie County WY-
416 PM MDT Sat May 9 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN KIMBALL...
SOUTHWESTERN BANNER AND EAST CENTRAL LARAMIE COUNTIES THROUGH 445 PM
MDT...

At 416 PM MDT, Doppler radar was tracking a strong thunderstorm near
Gun Barrel, or 29 miles northeast of Cheyenne, moving east at 45 mph.

HAZARD...Wind gusts of 50 to 55 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Pine Bluffs, Albin, Egbert, and Pine Bluffs Municipal Airport.

This includes the following highways...
 Interstate 80 in Wyoming between mile markers 392 and 402.
 Interstate 80 in Nebraska between mile markers 1 and 5.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4127 10449 4138 10447 4143 10435 4146 10383
      4105 10402
TIME...MOT...LOC 2216Z 286DEG 39KT 4137 10432

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...55 MPH

Natoli