Alert archive / Nebraska / Flash Flood Warnings in 2026

Flash Flood Warning 28, NWS Cheyenne, WY

September 18, 2026Dawes County, Sioux County, Nebraska

NWS Cheyenne, WY issued this flash flood warning at Sep 18, 2026, 9:12 PM MDT for Dawes County, Sioux County, Nebraska. It was in force for 103 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 18, 2026, 9:12 PM MDT (03:12 UTC)
Expired: Sep 18, 2026, 10:55 PM MDT
In force: 103 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

Counties Dawes County, NE, Sioux County, NE

The radar

The Rapid City radar (KUDX), 171 km from the middle of the area, began a volume at 03:12 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 3.2 hours before the alert went out and 164 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 404 J/kg
Mixed-layer CIN: -164 J/kg
Mixed-layer LCL: 1033 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -25 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

267 
WGUS55 KCYS 190312
FFWCYS
NEC045-165-190515-
/O.NEW.KCYS.FF.W.0028.260919T0312Z-260919T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
912 PM MDT Fri Sep 18 2026

The National Weather Service in Cheyenne has issued a

* Flash Flood Warning for...
  The South Fork Burn Scar in...
  Western Dawes County in the panhandle of Nebraska...
  East Central Sioux County in the panhandle of Nebraska...

* Until 1115 PM MDT.

* At 912 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain over the South Fork Burn Scar. Between 0.5 and 1 inch of
  rain has fallen. Additional rainfall amounts up to 1.5 inches are
  possible in the warned area. Flash flooding is ongoing or expected
  to begin shortly. Excessive rainfall over the burn scar will result
  in debris flow moving through the Soldier Creek and the White River
  drainages. The debris flow can consist of rock, mud, vegetation and
  other loose materials.

  HAZARD...Flash flooding caused by thunderstorms in and around the
           South Fork Burn Scar.

  SOURCE...Radar indicated.

  IMPACT...Flooding of areas in and around the South Fork Burn Scar.

* Some locations that will experience flash flooding include...
  Crawford, Fort Robinson State Park and Soldier Creek Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause
extensive and severe flash flooding of creeks...streams...and ditches
in the South Fork Burn Scar. Severe debris flows can also be
anticipated across roads. Roads and driveways may be washed away in
places. If you encounter flood waters...climb to safety.

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

&&

LAT...LON 4263 10348 4262 10354 4265 10363 4270 10369
      4273 10366 4276 10357 4273 10343 4268 10339
      4263 10346

FLASH FLOOD...RADAR INDICATED

$$

MN

1 follow-up statement

755 
WGUS75 KCYS 190455
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
1055 PM MDT Fri Sep 18 2026

NEC045-165-190505-
/O.CAN.KCYS.FF.W.0028.000000T0000Z-260919T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Dawes NE-Sioux NE-
1055 PM MDT Fri Sep 18 2026

...FLASH FLOOD WARNING FOR THE SOUTH FORK BURN SCAR IS CANCELLED FOR
WESTERN DAWES AND EAST CENTRAL SIOUX COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

&&

LAT...LON 4263 10348 4262 10354 4265 10363 4270 10369
      4273 10366 4276 10357 4273 10343 4268 10339
      4263 10346

$$

AM

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Cheyenne, WY wrote its last area forecast discussion before this flash flood warning went out at Sep 18, 5:38 PM MDT, 3 hours 34 minutes earlier. Its key messages:

Active with scattered to numerous showers and thunderstorms into the weekend. Strong to marginally severe thunderstorms may return to the area as a potent Pacific storm system moves into Wyoming Saturday and Saturday night.
Active weather with cooler temperatures expected for much of the upcoming week.

Area forecast discussion, Sep 18, 5:38 PM MDT, 3 hours 34 minutes before

Area Forecast Discussion
National Weather Service Cheyenne WY
538 PM MDT Fri Sep 18 2026

.KEY MESSAGES...

- Active with scattered to numerous showers and thunderstorms
  into the weekend. Strong to marginally severe thunderstorms
  may return to the area as a potent Pacific storm system moves
  into Wyoming Saturday and Saturday night.

- Active weather with cooler temperatures expected for much of
  the upcoming week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 259 PM MDT Fri Sep 18 2026

An active evening and weekend is in store for us. The upper level
low is further south than what the models originally had when
comparing current satellite Water vapor to global model outputs. The
position of the upper level low will really be important over the
next 48 to 72 hours. There is a low amplitude ridge over the
southern plains that if the central pressure shifts a little west
will slow down this low. If that occurs, expect heavy rain
showers and borderline severe to severe thunderstorms over the
weekend. Judging by its current speed and anticipated trajectory
this low is more likely to straddle the Colorado/Wyoming giving
us decent widespread rainfall but a little bit less likely on
the severe aspect. Hi-res guidance puts about 500 to 1000 joules
east of I-25. There are some pockets of 2,000 joules which may
be over done with the okay lapse rates between 6.5 to 7.0c and
700mb temperatures between 8 and 10C. Some cold air will be
following this low dropping 700mb temperatures from 10C to 6C
leafing to high temperatures slowly dropping through the
weekend. By Sunday the high temperatures are in the 60's and the
forecast area may be a little too cool for severe weather but
heavy rainfall looks to be a daily afternoon and evening
occurrence.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 259 PM MDT Fri Sep 18 2026

Forecast for next week looks to remain largely the same from day
to day under weak pressure gradients aloft with a few chances
for some scattered precipitation, but otherwise a cool start to
the weak with a slow and steady warming trend through the
remainder of. Upper level pattern will consist of weak ridging
trying to build in on Monday, but this will be overtaken by a
weak low lifting up from California and slowly progressing
across the region through the end of the forecast period. At the
surface, Monday will see our forecast region in a post-frontal
environment, with a weak boundary then sitting across the WY/NE
border area and then lifting east-northeast as a warm front into
the later days of the week. Under this pattern Monday will be
the coolest day of the forecast period as widespread highs
generally sit in the 60's to right around 70 in the warmest
spots. Increasing warmth then expected as warmer air from the
southwest moves across the region, but don't expect a crazy
warmup as we increase only 1-3 degrees each day, keeping the
region mostly in the 70's through the week until Thursday when a
few more 80's may finally begin popping up. A brief blip of
moisture may produce increased chances of showers and storms on
Tuesday as the California low lifts up, but without a stout
forcing mechanism don't expect much outside of general showers
and thunderstorms and coverage isolated to scattered at best.
Otherwise, a few isolated showers or storms possible each day as
well with nothing impactful expected.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 531 PM MDT Fri Sep 18 2026

A rather tricky forecast for terminals with all flight category
rules on the table. Heavy thunderstorms are spreading east,
currently near KCYS and KLAR. Visibility drops down to 2SM
possible, wind gusts to 45 knots and CIGs reduced to 2 kft
possible. Shower and storm activity becomes more widespread as
it progresses into the NE Panhandle. Post storms a near
saturated surface layer and light winds will be favorable for
widespread fog for the NE Panhandle terminals. The window for
fog development is from around 9z to 16z. Conditions improve in
the mid to late morning, but another round of showers and
thunderstorms in the afternoon hours is expected to bring
similar forecast conditions as this evening.

&&

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

&&

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

In the hours before

Special weather statement, Sep 18, 7:40 PM MDT, 1 hour 32 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
740 PM MDT Fri Sep 18 2026

NEZ019-020-096-WYZ108-190230-
Scotts Bluff NE-South Sioux NE-Banner NE-Goshen County WY-
740 PM MDT Fri Sep 18 2026

...STRONG THUNDERSTORMS WILL IMPACT SCOTTS BLUFF...NORTHWESTERN
BANNER...SOUTHWESTERN SIOUX AND SOUTHEASTERN GOSHEN COUNTIES THROUGH
830 PM MDT...

At 739 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 12 miles northeast of Lingle to Henry to near
La Grange. Movement was east at 25 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Scottsbluff, Torrington, Gering, Mitchell, Terrytown, Morrill, Lyman,
Henry, Huntley, Wildcat Hills State Recreation Area, Hawk Springs
Reservoir, Stegall, Southern Hills Estates, Scotts Bluff County
Fairground, Torrington Municipal Airport, Hawk Springs State
Recreation Area, Hawk Springs, Scotts Bluff National Monument,
Hubbard Hill, and Scottsbluff Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4232 10371 4190 10359 4167 10365 4170 10434
      4200 10426 4232 10426
TIME...MOT...LOC 0139Z 284DEG 23KT 4226 10415 4198 10405 4166 10413

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

Natoli

Local storm report, Sep 18, 7:56 PM MDT, 1 hour 16 minutes before

Preliminary Local Storm Report
National Weather Service Cheyenne WY
756 PM MDT Fri Sep 18 2026

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

0747 PM     Tstm Wnd Gst     2 E Torrington          42.07N 104.15W
09/18/2026  M60 MPH          Goshen             WY   ASOS

            ASOS station KTOR Torrington Airport - Tor.

&&

RV

Local storm report, Sep 18, 8:11 PM MDT, 1 hour 1 minute before

Preliminary Local Storm Report
National Weather Service Cheyenne WY
811 PM MDT Fri Sep 18 2026

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

0759 PM     Tstm Wnd Gst     2 SW Harrison           42.67N 103.91W
09/18/2026  M62 MPH          Sioux              NE   Public

            Personal weather station.

&&

Special weather statement, Sep 18, 8:42 PM MDT, 30 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
842 PM MDT Fri Sep 18 2026

NEZ054-055-190315-
Kimball NE-Cheyenne NE-
842 PM MDT Fri Sep 18 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN CHEYENNE AND EASTERN
KIMBALL COUNTIES THROUGH 915 PM MDT...

At 842 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms along a line extending from near Kimball to near Dix to
8 miles south of Potter. Movement was northeast at 25 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Kimball, Potter, Dix, Kimball Municipal Airport, and Kimball County
Fairgrounds.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4112 10360 4122 10373 4139 10354 4130 10325
      4100 10316 4101 10357
TIME...MOT...LOC 0242Z 242DEG 21KT 4123 10357 4121 10346 4111 10337

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Natoli

Special weather statement, Sep 18, 8:44 PM MDT, 28 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
844 PM MDT Fri Sep 18 2026

NEZ003-019-021-096-190330-
Scotts Bluff NE-Box Butte NE-Morrill NE-South Sioux NE-
844 PM MDT Fri Sep 18 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN BOX BUTTE...
NORTHEASTERN SCOTTS BLUFF...NORTHWESTERN MORRILL AND SOUTHEASTERN
SIOUX COUNTIES THROUGH 930 PM MDT...

At 844 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles south of Agate Fossil Beds National
Monument to near Lake Alice. Movement was east at 10 mph.

HAZARD...Wind gusts up to 50 mph and pea 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...
Flahertys Corner, Lake Alice, and Lake Alice Number 2.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4236 10338 4195 10334 4197 10374 4234 10383
TIME...MOT...LOC 0244Z 255DEG 10KT 4229 10373 4204 10366

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

Natoli

Special weather statement, Sep 18, 9:04 PM MDT, 8 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
904 PM MDT Fri Sep 18 2026

NEZ002-003-095-096-190345-
Box Butte NE-Dawes NE-North Sioux NE-South Sioux NE-
904 PM MDT Fri Sep 18 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN BOX BUTTE...SOUTHERN
DAWES AND EAST CENTRAL SIOUX COUNTIES THROUGH 945 PM MDT...

At 904 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Flahertys Corner, or 34 miles southwest of Chadron,
moving east at 35 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...
Hemingford, Box Butte Campground, Box Butte County Fairgrounds, Box
Butte Reservoir, Marsland, Belmont, and Box Butte Dam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4235 10359 4255 10360 4265 10293 4223 10286
TIME...MOT...LOC 0304Z 267DEG 33KT 4246 10347

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

Natoli

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 18, 7:10 PM MDT	Special Weather Statement	CYS	Kimball	50 min
Sep 18, 7:35 PM MDT	Special Weather Statement	CYS	Sioux	25 min
Sep 18, 7:40 PM MDT	Special Weather Statement	CYS	Scotts Bluff	50 min
Sep 18, 7:42 PM MDT	Severe Thunderstorm Warning	CYS	Sioux	48 min
Sep 18, 7:56 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Scotts Bluff, Sioux	49 min
Sep 18, 8:22 PM MDT	Severe Thunderstorm Warning	CYS	Dawes, Sioux	53 min
Sep 18, 8:42 PM MDT	Special Weather Statement	CYS	Kimball	33 min
Sep 18, 8:44 PM MDT	Special Weather Statement	CYS	Scotts Bluff	46 min
Sep 18, 9:04 PM MDT	Special Weather Statement	CYS	Box Butte	41 min
Sep 19, 3:30 PM MDT	Special Weather Statement	CYS	Dawes	45 min
Sep 19, 4:15 PM MDT	Severe Thunderstorm Warning	CYS	Dawes	45 min
Sep 19, 4:16 PM MDT	Special Weather Statement	CYS	Box Butte	44 min
Sep 19, 4:57 PM MDT	Severe Thunderstorm Warning	CYS	Dawes	43 min
Sep 19, 4:58 PM MDT	Special Weather Statement	CYS	Box Butte	47 min

Nearby

Flash Flood Warnings in Nebraska, 2026 Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.