Alert archive / Nebraska / Flash Flood Warnings in 2021

Flash Flood Warning 6, NWS Hastings, NE

August 7, 2021Polk County, Nebraska

NWS Hastings, NE issued this flash flood warning at Aug 7, 2021, 9:44 PM CDT for Polk County, Nebraska. It was in force for 6 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: Aug 7, 2021, 9:44 PM CDT (02:44 UTC)
Expired: Aug 8, 2021, 3:45 AM CDT
In force: 6 hr
Issued by: NWS Hastings, NE
Area: Storm-based polygon
Flood severity: None

County Polk County, NE

The radar

The Grand Island radar (KUEX), 108 km from the middle of the area, began a volume at 02:47 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
Aug 7, 9:55 PM CDT	FLASH FLOOD	3 W Osceola, NE	FLOODED SECTIONS OF THE HIGHWAY NEAR HIGHWAY 81 AND 92 JUNCTION.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.7 hours before the alert went out and 113 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: 2933 J/kg
Mixed-layer CIN: -124 J/kg
Mixed-layer LCL: 1327 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 195 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 3.3

Open this sounding in Storm Lab

The text

As transmitted.

343 
WGUS53 KGID 080244
FFWGID
NEC143-080845-
/O.NEW.KGID.FF.W.0006.210808T0244Z-210808T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Hastings NE
944 PM CDT Sat Aug 7 2021

The National Weather Service in Hastings has issued a

* Flash Flood Warning for...
  Southern Polk County in east central Nebraska...

* Until 345 AM CDT Sunday.

* At 944 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Additional rainfall amounts up to 2 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...
  Stromsburg, Osceola, Shelby and Polk.

This includes the following streams and drainages...
  Clear Creek, Big Blue River, Davis Creek, Prairie Creek and North 
  Branch Big Blue River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4111 9783 4125 9760 4136 9737 4118 9737
      4117 9737 4109 9753 4105 9767 4105 9771
      4105 9773 4105 9775 4105 9777 4105 9778
      4105 9780 4105 9781 4105 9783 4106 9783
      4110 9783

FLASH FLOOD...RADAR INDICATED

$$

Wesely

1 follow-up statement

209 
WGUS73 KGID 080841
FFSGID

Flash Flood Statement
National Weather Service Hastings NE
341 AM CDT Sun Aug 8 2021

NEC143-080851-
/O.EXP.KGID.FF.W.0006.000000T0000Z-210808T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Polk NE-
341 AM CDT Sun Aug 8 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 345 AM CDT EARLY THIS MORNING 
FOR SOUTHERN POLK COUNTY...

The Flash Flood Warning has been replaced with a Flood Warning, 
which is now in effect through 1230 PM CDT.

LAT...LON 4111 9783 4125 9760 4136 9737 4118 9737
      4117 9737 4109 9753 4105 9767 4105 9771
      4105 9773 4105 9775 4105 9777 4105 9778
      4105 9780 4105 9781 4105 9783 4106 9783
      4110 9783

$$

Wesely

The office that day

Everything else NWS Hastings, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 7, 7:25 PM CDT	Special Weather Statement	GID	Polk	35 min
Aug 7, 7:28 PM CDT	Severe Thunderstorm Warning	GID	Adams, Clay, Nuckolls, Webster	32 min
Aug 7, 7:37 PM CDT	Special Weather Statement	GID	Webster	23 min
Aug 7, 7:46 PM CDT	Severe Thunderstorm Warning	GID	Polk	29 min
Aug 7, 7:54 PM CDT	Severe Thunderstorm Warning	GID	Clay, Fillmore, Hamilton, York	51 min
Aug 7, 7:59 PM CDT	Severe Thunderstorm Warning	GID	Adams, Clay, Hall, Hamilton, Kearney, Merrick	31 min
Aug 7, 8:10 PM CDT	Severe Thunderstorm Warning	GID	Hall, Hamilton, Merrick, Nance, Polk, York	50 min
Aug 7, 8:20 PM CDT	Special Weather Statement	GID	Franklin	25 min
Aug 7, 8:23 PM CDT	Severe Thunderstorm Warning	GID	Franklin, Harlan, Webster	52 min
Aug 7, 8:24 PM CDT	Severe Thunderstorm Warning	GID	Adams, Clay, Hall, Hamilton	29 min
Aug 7, 8:46 PM CDT	Severe Thunderstorm Warning	GID	Adams, Buffalo, Hall, Kearney	44 min
Aug 7, 8:57 PM CDT	Severe Thunderstorm Warning	GID	Hamilton, Merrick, Polk, York	33 min
Aug 7, 9:03 PM CDT	Severe Thunderstorm Warning	GID	Thayer	42 min
Aug 7, 9:27 PM CDT	Severe Thunderstorm Warning	GID	Hall, Hamilton, Howard, Merrick	33 min
Aug 7, 9:30 PM CDT	Areal Flood Advisory	GID	Hall, Hamilton, Merrick, Polk, York	9 hr
Aug 7, 9:30 PM CDT	Severe Thunderstorm Warning	GID	Merrick, Nance, Polk	30 min
Aug 7, 9:55 PM CDT	Severe Thunderstorm Warning	GID	Hall, Howard, Merrick	17 min
Aug 7, 10:03 PM CDT	Special Weather Statement	GID	Polk	27 min
Aug 8, 1:24 AM CDT	Special Weather Statement	GID	Webster	36 min
Aug 8, 1:32 AM CDT	Severe Thunderstorm Warning	GID	Webster	28 min
Aug 8, 2:05 AM CDT	Special Weather Statement	GID	Adams, Webster	25 min
Aug 8, 2:37 AM CDT	Special Weather Statement	GID	Hall	23 min
Aug 8, 3:04 AM CDT	Special Weather Statement	GID	Hall	26 min
Aug 8, 3:36 AM CDT	Areal Flood Warning	GID	Polk	7 hr
Aug 8, 2:09 PM CDT	Heat Advisory	GID	Adams, Buffalo, Clay, Fillmore, Franklin, Hall and 10 more	55 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.