Alert archive / Nebraska / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS Cheyenne, WY

July 13, 2021Scotts Bluff County, Nebraska

NWS Cheyenne, WY issued this flash flood warning at Jul 13, 2021, 11:07 PM MDT for Scotts Bluff County, Nebraska. It was in force for 2 hr. 4 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: Jul 13, 2021, 11:07 PM MDT (05:07 UTC)
Expired: Jul 14, 2021, 1:23 AM 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), 119 km from the middle of the area, began a volume at 05:09 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 13, 11:21 PM MDT	HEAVY RAIN 1.37	Ne Scottsbluff, NE	KNEB STATION MANAGER.
Jul 13, 11:30 PM MDT	FLASH FLOOD	Scottsbluff, NE	REPORTS OF NUMEROUS STREETS FLOODED FROM HEAVY RAIN. REPORT CORRECTED FOR TIME.
Jul 13, 11:30 PM MDT	HEAVY RAIN 1.06	N Scottsbluff, NE	REPORT RECEIVED VIA FACEBOOK.
Jul 13, 11:49 PM MDT	FLASH FLOOD	1 Ese Scottsbluff, NE	REPORT FROM MPING: STREET/ROAD FLOODING; STREET/ROAD CLOSED; VEHICLES STRANDED.

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 00:00Z, 5.1 hours before the alert went out and 230 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2543 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: -22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

474 
WGUS55 KCYS 140507
FFWCYS
NEC157-140800-
/O.NEW.KCYS.FF.W.0005.210714T0507Z-210714T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
1107 PM MDT Tue Jul 13 2021

The National Weather Service in Cheyenne has issued a

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

* Until 200 AM MDT.

* At 1107 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across 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, Mitchell, Terrytown, Morrill, Lyman, Hubbard 
  Hill, Scotts Bluff National Monument, Scottsbluff Airport, 
  Stegall, Lake Alice, Lake Minatare Campground and Lake Minatare.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4199 10405 4199 10341 4190 10345 4174 10369
      4178 10405

FLASH FLOOD...RADAR INDICATED

$$

Claycomb

1 follow-up statement

075 
WGUS75 KCYS 140723
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
123 AM MDT Wed Jul 14 2021

NEC157-140733-
/O.CAN.KCYS.FF.W.0005.000000T0000Z-210714T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Scotts Bluff NE-
123 AM MDT Wed Jul 14 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL SCOTTS BLUFF 
COUNTY...

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

LAT...LON 4199 10405 4199 10341 4190 10345 4174 10369
      4178 10405

$$

Claycomb

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 13, 10:30 PM MDT	Special Weather Statement	CYS	Box Butte, Scotts Bluff	45 min
Jul 13, 10:54 PM MDT	Areal Flood Advisory	CYS	Scotts Bluff	17 min
Jul 13, 11:08 PM MDT	Special Weather Statement	CYS	Banner	37 min
Jul 13, 11:16 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball, Morrill, Scotts Bluff	44 min
Jul 13, 11:31 PM MDT	Flash Flood Warning	CYS	Banner, Morrill, Scotts Bluff	2 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.