Alert archive / Nebraska / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Cheyenne, WY

July 1, 2021Scotts Bluff County, Nebraska

NWS Cheyenne, WY issued this flash flood warning at Jul 1, 2021, 2:14 PM MDT for Scotts Bluff County, Nebraska. It was in force for 2 hr. 1 report 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: Jul 1, 2021, 2:14 PM MDT (20:14 UTC)
Expired: Jul 1, 2021, 4:15 PM MDT
In force: 2 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

County Scotts Bluff County, NE

The radar

The Cheyenne radar (KCYS), 125 km from the middle of the area, began a volume at 20:16 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
Jul 1, 2:31 PM MDT	FLASH FLOOD	Scottsbluff, NE	AVENUE B AND WEST 29TH AND AVENUE G FLOODED IN THE TOWN OF SCOTTSBLUFF PER EMERGENCY MANAGER.

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

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 8.2 hours before the alert went out and 228 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: 240 J/kg
Mixed-layer CIN: -180 J/kg
Mixed-layer LCL: 1308 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 9 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

716 
WGUS55 KCYS 012014
FFWCYS
NEC157-012215-
/O.NEW.KCYS.FF.W.0003.210701T2014Z-210701T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
214 PM MDT Thu Jul 1 2021

The National Weather Service in Cheyenne has issued a

* Flash Flood Warning for...
  Central Scotts Bluff County in the panhandle of Nebraska...

* Until 415 PM MDT.

* At 214 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.25 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.75 to 1.25 
  inches are possible in the warned area. Flash flooding is ongoing 
  or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  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...
  Scottsbluff, Gering, Terrytown and Scottsbluff Airport.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 4191 10377 4193 10372 4192 10363 4188 10357
      4186 10358 4183 10364 4187 10375

FLASH FLOOD...RADAR INDICATED

$$

Allen

1 follow-up statement

111 
WGUS75 KCYS 012211
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
411 PM MDT Thu Jul 1 2021

NEC157-012221-
/O.EXP.KCYS.FF.W.0003.000000T0000Z-210701T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Scotts Bluff NE-
411 PM MDT Thu Jul 1 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 415 PM MDT THIS AFTERNOON FOR 
CENTRAL SCOTTS BLUFF COUNTY...

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

LAT...LON 4191 10377 4193 10372 4192 10363 4188 10357
      4186 10358 4183 10364 4187 10375

$$

Hammer

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 1, 12:58 PM MDT	Areal Flood Advisory	CYS	Scotts Bluff	2 hr
Jul 1, 1:14 PM MDT	Areal Flood Advisory	CYS	Scotts Bluff, Sioux	3 hr

Nearby

Flash Flood Warnings in Nebraska, 2021 Every flash flood warning in 2021

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.