Alert archive / Nebraska / Flash Flood Warnings in 2026

Flash Flood Warning 25, NWS Cheyenne, WY

September 5, 2026Box Butte County, Nebraska

NWS Cheyenne, WY issued this flash flood warning at Sep 5, 2026, 5:07 PM MDT for Box Butte County, Nebraska. It was in force for 3 hr. 14 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 5, 2026, 5:07 PM MDT (23:07 UTC)
Expired: Sep 5, 2026, 8:00 PM MDT
In force: 3 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

County Box Butte County, NE

The radar

The Cheyenne radar (KCYS), 191 km from the middle of the area, began a volume at 23:10 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.

What was reported inside it

Time	Report	Where	Remark
Sep 5, 5:07 PM MDT	FLASH FLOOD	Alliance, NE	Multiple Facebook reports of roadways having rivers running down them.
Sep 5, 5:09 PM MDT	FLASH FLOOD	Alliance, NE	Report from mPING: River/Creek overflowing; Cropland/Yard/Basement Flooding.
Sep 5, 5:20 PM MDT	FLASH FLOOD	Alliance, NE	Public report on Facebook of flooded roadways in Alliance. Flood waters cross multiple roads.
Sep 5, 5:35 PM MDT	FLASH FLOOD	Alliance, NE	Public report with an image on Facebook of a car submerged in water under and overpass in Alliance.
Sep 5, 5:45 PM MDT	RAIN 3.19	0.7 Wnw Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:47 PM MDT	RAIN 2.52	0.1 Nne Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:48 PM MDT	FLASH FLOOD	Alliance, NE	Alliance Police Department send out a statement saying residents are "urged to stop driving around town and remain where they are unless travel is absolutely necessary." This is in reference to the flash flooding ongoing around town.
Sep 5, 5:48 PM MDT	RAIN 3.03	0.6 Nw Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:49 PM MDT	RAIN 2.69	0.7 Nnw Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:50 PM MDT	RAIN 2.36	1 Nw Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:50 PM MDT	RAIN 2.46	0.4 N Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 5:52 PM MDT	RAIN 1.89	0.4 Nne Alliance, NE	Heavy rain reported with personal weather station in Alliance.
Sep 5, 6:13 PM MDT	RAIN 4.57	3 Sw Alliance, NE	Mesonet station 3 miles SW of Alliance reported 4.57 inches of rain with the storms this afternoon.
Sep 5, 7:05 PM MDT	FLASH FLOOD	Alliance, NE	Public sent in video of fast flowing water down a street in Alliance.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 6 storm reports to this flash flood warning; the first came 0 minutes after it went out.

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 text

As transmitted.

594 
WGUS55 KCYS 052307
FFWCYS
NEC013-060200-
/O.NEW.KCYS.FF.W.0025.260905T2307Z-260906T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
507 PM MDT Sat Sep 5 2026

The National Weather Service in Cheyenne has issued a

* Flash Flood Warning for...
  Southeastern Box Butte County in the panhandle of Nebraska...

* Until 800 PM MDT.

* At 507 PM MDT, gauge reports indicated thunderstorms producing
  heavy rain across the warned area. Between 1.5 and 2 inches of rain
  have fallen. Additional rainfall amounts up to 1 inch are possible
  in the warned area. Flash flooding is ongoing or expected to begin
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Gauges reported.

  IMPACT...Flash flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other poor
           drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Alliance.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4210 10293 4214 10289 4212 10283 4207 10283
      4204 10292

FLASH FLOOD...GAUGE INDICATED

$$

SF

1 follow-up statement

510 
WGUS75 KCYS 060152
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
752 PM MDT Sat Sep 5 2026

NEC013-060202-
/O.EXP.KCYS.FF.W.0025.000000T0000Z-260906T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Box Butte NE-
752 PM MDT Sat Sep 5 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR
SOUTHEASTERN BOX BUTTE COUNTY...

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

&&

LAT...LON 4210 10293 4214 10289 4212 10283 4207 10283
      4204 10292

$$

SF

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 5, 2:53 PM MDT, 2 hours 14 minutes earlier. Its 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.

Area forecast discussion, Sep 5, 2:53 PM MDT, 2 hours 14 minutes before

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

In the hours before

Special weather statement, Sep 5, 4:09 PM MDT, 58 minutes before

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

NEZ021-052245-
Morrill NE-
409 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MORRILL COUNTY
THROUGH 445 PM MDT...

At 409 PM MDT, Doppler radar was tracking a strong thunderstorm near
Broadwater, or 31 miles south of Alliance, moving northeast at 15
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...
Broadwater and The Intersection Of Highway 385 And 92.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4156 10301 4166 10305 4182 10281 4163 10269
TIME...MOT...LOC 2209Z 239DEG 14KT 4165 10293

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

Vasquez

Special weather statement, Sep 5, 4:15 PM MDT, 52 minutes before

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

NEZ020-054-052245-
Kimball NE-Banner NE-
415 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN KIMBALL AND
SOUTHEASTERN BANNER COUNTIES THROUGH 445 PM MDT...

At 415 PM MDT, Doppler radar was tracking a strong thunderstorm over
Kimball, 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...
Kimball, Dix, Kimball Municipal Airport, and Kimball County
Fairgrounds.

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 4115 10375 4125 10380 4143 10354 4120 10340
TIME...MOT...LOC 2215Z 247DEG 7KT 4125 10366

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

Vasquez

Local storm report, Sep 5, 4:39 PM MDT, 28 minutes before

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

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

0430 PM     Hail             4 SSW Alliance          42.05N 102.90W
09/05/2026  M2.00 Inch       Box Butte          NE   Trained Spotter

            Trained Spotter reported 2 inch hail 4 miles
            SSW of Alliance.

&&

Special weather statement, Sep 5, 4:44 PM MDT, 23 minutes before

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

NEZ021-052315-
Morrill NE-
444 PM MDT Sat Sep 5 2026

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL MORRILL COUNTY
THROUGH 515 PM MDT...

At 444 PM MDT, Doppler radar was tracking a strong thunderstorm near
Broadwater, or 28 miles south of Alliance, moving northeast at 10
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.

This storm will remain over mainly rural areas of east central
Morrill County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4161 10293 4171 10299 4182 10281 4166 10270
TIME...MOT...LOC 2244Z 237DEG 10KT 4169 10290

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

Vasquez

Local storm report, Sep 5, 5:04 PM MDT, 3 minutes before

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

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

0500 PM     Hail             4 SSW Alliance          42.05N 102.91W
09/05/2026  E1.00 Inch       Box Butte          NE   Storm Chaser

            Storm chaser live stream shows accumulating
            hail along Highway 387 southwest of
            Alliance. The shoulders were completed
            covered, with the left lane completely
            covered at times.

&&

Local storm report, Sep 5, 5:06 PM MDT, 1 minute before

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

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

0505 PM     Hail             3 SSW Alliance          42.06N 102.90W
09/05/2026  M2.00 Inch       Box Butte          NE   Trained Spotter

            Trained Spotter reports accumulating hail up
            to 2 inches in diameter and around 3 inches
            deep along Highway 385 SSW of Alliance.

&&

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 2:43 PM MDT	Special Weather Statement	CYS	Dawes	32 min
Sep 5, 3:00 PM MDT	Special Weather Statement	CYS	Box Butte	30 min
Sep 5, 3:09 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte	36 min
Sep 5, 3:13 PM MDT	Special Weather Statement	CYS	Box Butte	32 min
Sep 5, 3:22 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte	23 min
Sep 5, 3:44 PM MDT	Flash Flood Warning	CYS	Box Butte, Dawes	3 hr
Sep 5, 3:44 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte	46 min
Sep 5, 3:47 PM MDT	Special Weather Statement	CYS	Box Butte	28 min
Sep 5, 4:09 PM MDT	Special Weather Statement	CYS	Morrill	36 min
Sep 5, 4:15 PM MDT	Special Weather Statement	CYS	Kimball	30 min
Sep 5, 4:22 PM MDT	Severe Thunderstorm Warning Considerable damage threat	CYS	Box Butte, Morrill	38 min
Sep 5, 4:30 PM MDT	Areal Flood Advisory	CYS	Box Butte	37 min
Sep 5, 4:44 PM MDT	Special Weather Statement	CYS	Morrill	31 min
Sep 5, 4:57 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Morrill	33 min
Sep 5, 5:03 PM MDT	Severe Thunderstorm Warning	CYS	Morrill	27 min
Sep 5, 5:08 PM MDT	Special Weather Statement	CYS	Banner	37 min
Sep 5, 5:24 PM MDT	Special Weather Statement	CYS	Morrill	36 min
Sep 5, 5:26 PM MDT	Special Weather Statement	CYS	Morrill	34 min
Sep 5, 5:30 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Morrill	30 min
Sep 5, 5:32 PM MDT	Severe Thunderstorm Warning	CYS	Morrill	28 min
Sep 5, 5:33 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Morrill, Scotts Bluff	42 min
Sep 5, 5:35 PM MDT	Special Weather Statement	CYS	Cheyenne	25 min
Sep 5, 5:40 PM MDT	Severe Thunderstorm Warning	CYS	Morrill	50 min
Sep 5, 5:59 PM MDT	Severe Thunderstorm Warning	CYS	Morrill	31 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; local storm reports from the same archive; radar from the NEXRAD Level II archive.