Severe Thunderstorm Warning 331, NWS Cheyenne, WY

063 
WWUS55 KCYS 052344
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
544 PM MDT Sat Sep 5 2026

NEC123-060000-
/O.CON.KCYS.SV.W.0331.000000T0000Z-260906T0000Z/
Morrill NE-
544 PM MDT Sat Sep 5 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM MDT
FOR CENTRAL MORRILL COUNTY...

At 544 PM MDT, a severe thunderstorm was located near Northport, or
26 miles south of Alliance, moving northeast at 15 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Trained weather spotters.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Bridgeport, Northport, and Bridgeport State Recreation Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4166 10312 4174 10322 4186 10301 4172 10289
TIME...MOT...LOC 2344Z 225DEG 12KT 4175 10306 

HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Vasquez

388 
WWUS55 KCYS 060000
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
600 PM MDT Sat Sep 5 2026

NEC123-060009-
/O.EXP.KCYS.SV.W.0331.000000T0000Z-260906T0000Z/
Morrill NE-
600 PM MDT Sat Sep 5 2026

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MORRILL COUNTY WILL
EXPIRE AT 600 PM MDT...

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
the Panhandle of Nebraska.

Remember, a Severe Thunderstorm Warning still remains in effect for
Central Morrill County until 630 PM.

&&

LAT...LON 4166 10312 4174 10322 4186 10301 4172 10289
TIME...MOT...LOC 2359Z 225DEG 12KT 4178 10302 

$$

Vasquez

Area Forecast Discussion
National Weather Service Cheyenne WY
253 PM MDT Sat Sep 5 2026

.KEY MESSAGES...

- Chances for afternoon and evening thunderstorms continue until
  mid week. Strong gusty winds and brief heavy rainfall are the
  primary threats.

- A temporary drying trend begins Mid-week and possibly
  continues through the end of next week.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 235 PM MDT Sat Sep 5 2026

Not too many changes to the previous forecast package with
shower and thunderstorms, some strong with heavy rainfall,
remaining the primary concern today. Overall, strong upper
level ridge axis is forecast to remain across the central Great
Plains for much of the weekend. Fall-like upper level trough
will meander its way across the Pacific NW coastline and move
inland on Sunday. Ahead of this trough, some shortwave energy
will eject northeast over Colorado and Wyoming along with a 100
knot jet max nudging east into the northern Front Range Sunday
night and Monday. Generally expect a slow cooling trend Sunday
and Monday as some cooler air makes its way into Central
Wyoming. Further east, surface winds are expected to shift into
the east or southeast, resulting in some upslope flow and minor
cooling over mainly southeast Wyoming.

Shallow convection from this morning has lifted northeast of the
area and dissipated. However, radar loop shows activity starting
to fire up again over the northern and central Nebraska
panhandle early this afternoon. Expect this trend to continue
through late this evening as coverage is likely going to
increase across the entire Nebraska Panhandle. Convective
parameters look favorable for scattered to numerous showers and
thunderstorms, which may linger past midnight across portions of
the southern panhandle. Meso Analysis shows MLCAPE of 1000 to
2000 j/kg (slightly higher SB) over mostly western Nebraska,
with values increasing a bit more through the afternoon as we
near the peak heating of the day. Severe thunderstorm potential
looks limited today, but can't rule out a few marginally severe
multicell clusters developing into this evening. Main limiting
factor is shear with 0-6km and overall effective shear around 20
to 25 knots, maybe up to 30 knots. Hodographs are fairly
straight, with some curvature across the southern Panhandle this
evening. Generally expect some very heavy rainfall with gusty
winds as high res guidance shows clusters of thunderstorms
forming and then building upshear into this evening. Can't
totally rule out some hail producers (including large hail) in
this area, but its not the most favorable environment this time
of the year. There is some considerable concern for some areal
flooding or localized flash flooding. Area of concern is not
generally known for flash flooding issues however. Kept POP
above 35 percent through midnight for Alliance, Sidney, and
Kimball Nebraska.

Another warm day for Sunday, but not quite as warm as guidance
suggests due to east to southeast upslope winds across the
plains. Similar weather pattern during the day with even higher
dewpoints due to some low level moisture advection. Model
soundings show some lingering CIN in the low to midlevels on
Sunday, likely due to the nocturnal convection early Sunday
morning. Upper level shortwave/vort max is not as strong as
today's forcing and arrives a bit later in the day, so expect
more isolated coverage of thunderstorms. Shear looks even more
marginal with around 20 knots of Bulk Shear by mid to late
afternoon. A few strong thunderstorms are possible, but having a
hard time with the severe potential with such limited 0-6 km
shear. Further west, may say some gusty winds associated with
shower and isolated thunderstorm activity as the leading edge of
the Pacific cold front and jet max aloft moves into central
Wyoming by late Sunday evening. Increased POP across the whole
area, but mainly for later in the day (after 6 PM) due to the
better forcing.

Drier air forecast to push into the area on Monday behind the
front with some cooler air. Expect a lower coverage of
thunderstorms, mainly located south along the I-80 corridor and
the mountains. High temperatures in the mid 70s to mid 80s are
expected for most of southeast Wyoming, with highs in the low
90s for western Nebraska. It will be windy during the day with
southwest winds between 25 to 35 MPH with gusts around 45 MPH
likely along and west of Interstate 25.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Issued at 200 PM MDT Sat Sep 5 2026

The very persistent low pressure system loitering in the Pacific
Northwest will finally be ejecting eastward on Monday and Tuesday.
The models are trending towards a slightly more eastward and
amplified evolution of this low's passage, possibly influenced by a
stronger shortwave just ahead of it. Moisture content ahead of this
system seems to be on track with previous forecasts. PWAT values are
running about 2 to 3 standard deviations above climatology. The few
CAMs that go out to Monday evening do not show much in the way of
rainfall with most of the synoptic forcing staying well north of the
area. Regardless a few showers and storms from the afternoon will
linger through the early evening. Tuesday the western most lobe of
the upper level system will swing southeast to pass just north of
our area. With it a weak cold front will pass through. There is
enough moisture ahead of the front that a few storms are possible,
particularly for the southern NE Panhandle areas. No severe weather
is anticipated at this time for this round of storms before they
depart to our east. The front should cut afternoon highs by about 5
degrees, so that is nice. What isn't nice are the low humidity and
gusty winds behind it which could elevate fire weather conditions.

Post cold front Wednesday is also slightly cooler and drier.
The ridge that has been patiently waiting for its chance to
build back west will do so by Thursday. Downsloping flow from
the Intermountain West will act to heat us back up and keep us
dry. Continued gusty winds does mean fire weather will be the
topic of upcoming forecast. The type of pattern will continue
until our next Pacific upper level system arrives in the very
long term, hopefully with more rain.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1123 AM MDT Sat Sep 5 2026

Scattered thunderstorms are anticipated for the Nebraska
Panhandle terminals this afternoon and evening as a complex of
storms develops from north to southeast. Storms will be capable
of producing variable wind gusts to 50 knots, lightning, and
reduced vis from heavy rain, down to 2SM. The earliest onset is
around 20z at KBFF and KCDR and ending around 06z at KSNY. At
KLAR and KCYS the chances of storms is slightly lower, but the
latest high resolution model guidance does support at least a
few showers and storms in the vicinity. VFR conditions outside
of this storm activity at terminals through the rest of the
forecast period, though lowered CIGs behind storms may occur.
Breezy conditions at KRWL possible to 35 knots out of the
southwest this afternoon. Highly variable wind directions
possible post storms and during the overnight hours at KCDR,
KBFF, KAIA, and KSNY.

&&

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

&&

SHORT TERM...TJT
LONG TERM...RV
AVIATION...RV

Special Weather Statement
National Weather Service Cheyenne WY
508 PM MDT Sat Sep 5 2026

NEZ020-052345-
Banner NE-
508 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN SCOTTS BLUFF AND
NORTHEASTERN BANNER COUNTIES THROUGH 545 PM MDT...

At 508 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles east of Harrisburg, or 21 miles south of Scottsbluff, moving
northeast at 10 mph.

HAZARD...Wind gusts up to 40 mph and half inch 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...
Wrights Gap.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4146 10357 4157 10367 4170 10352 4170 10350
      4158 10337 4156 10337
TIME...MOT...LOC 2308Z 218DEG 9KT 4156 10354

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Vasquez

Preliminary Local Storm Report
National Weather Service Cheyenne WY
512 PM MDT Sat Sep 5 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0507 PM     Flash Flood      Alliance                42.10N 102.87W
09/05/2026                   Box Butte          NE   Public

            Multiple Facebook reports of roadways having
            rivers running down them.

0509 PM     Flash Flood      Alliance                42.10N 102.88W
09/05/2026                   Box Butte          NE   Public

            Report from mPING: River/Creek overflowing;
            Cropland/Yard/Basement Flooding.

&&

Special Weather Statement
National Weather Service Cheyenne WY
524 PM MDT Sat Sep 5 2026

NEZ019>021-060000-
Scotts Bluff NE-Morrill NE-Banner NE-
524 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN SCOTTS BLUFF...
NORTHWESTERN MORRILL AND NORTHEASTERN BANNER COUNTIES THROUGH 600 PM
MDT...

At 524 PM MDT, Doppler radar was tracking a strong thunderstorm over
Bridgeport State Recreation Area, or 29 miles southeast of
Scottsbluff, moving northeast at 10 mph.

HAZARD...Wind gusts up to 50 mph and half inch 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...
Bridgeport, Bayard, McGrew, Chimney Rock National Historic Site,
Northport, Bridgeport State Recreation Area, Angora, Morrill County
Fairgrounds, Wrights Gap, The Intersection Of Highway 385 And L62,
and South Bayard Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4158 10355 4170 10361 4190 10299 4164 10293
TIME...MOT...LOC 2324Z 227DEG 9KT 4169 10313

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Vasquez

Preliminary Local Storm Report
National Weather Service Cheyenne WY
526 PM MDT Sat Sep 5 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0520 PM     Flash Flood      Alliance                42.10N 102.87W
09/05/2026                   Box Butte          NE   Public

            Public report on Facebook of flooded
            roadways in Alliance. Flood waters cross
            multiple roads.

&&

Special Weather Statement
National Weather Service Cheyenne WY
526 PM MDT Sat Sep 5 2026

NEZ003-021-060000-
Box Butte NE-Morrill NE-
526 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN BOX BUTTE AND
NORTHEASTERN MORRILL COUNTIES THROUGH 600 PM MDT...

At 526 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles southwest of Alliance Municipal Airport, or 9 miles south of
Alliance, moving east at 10 mph.

HAZARD...Wind gusts up to 40 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...
Alliance Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4184 10301 4196 10312 4210 10281 4197 10267
      4193 10268
TIME...MOT...LOC 2326Z 254DEG 11KT 4196 10293

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Vasquez

Preliminary Local Storm Report
National Weather Service Cheyenne WY
529 PM MDT Sat Sep 5 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0527 PM     Hail             9 SSW Alliance          41.98N 102.94W
09/05/2026  M1.00 Inch       Morrill            NE   Trained Spotter

            Trained Spotter reported 1 inch hail along
            Highway 385, 9 miles SSW of Alliance.

&&