Alert archive / Wisconsin / Flash Flood Warnings in 2021

Flash Flood Warning 10, NWS La Crosse, WI

August 27, 2021Vernon County, Wisconsin

NWS La Crosse, WI issued this flash flood warning at Aug 27, 2021, 11:41 PM CDT for Vernon County, Wisconsin. It was in force for 4 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 27, 2021, 11:41 PM CDT (04:41 UTC)
Expired: Aug 28, 2021, 3:45 AM CDT
In force: 4 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

County Vernon County, WI

The radar

The La Crosse radar (KARX), 28 km from the middle of the area, began a volume at 04:41 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 28, 1:06 AM CDT	FLASH FLOOD	Chaseburg, WI	REPORTS OF ROAD DAMAGE FROM WATER AND SEVERAL MUD SLIDES IN THE WESTERN PORTIONS OF VERNON COUNTY.

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

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.7 hours before the alert went out and 223 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: 995 J/kg
Mixed-layer CIN: -68 J/kg
Mixed-layer LCL: 1707 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 148 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

224 
WGUS53 KARX 280441
FFWARX
WIC123-280745-
/O.NEW.KARX.FF.W.0010.210828T0441Z-210828T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
1141 PM CDT Fri Aug 27 2021

The National Weather Service in La Crosse has issued a

* Flash Flood Warning for...
  Western Vernon County in southwestern Wisconsin...

* Until 245 AM CDT.

* At 1141 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 of 1 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...
  Viroqua, Westby, Stoddard, Coon Valley, Springville, Liberty, and 
  Readstown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4372 9119 4372 9075 4342 9072 4342 9074
      4349 9121 4351 9122 4357 9123 4358 9123
      4359 9123 4359 9124 4364 9125

FLASH FLOOD...RADAR INDICATED

$$

KDS

2 follow-up statements

511 
WGUS53 KARX 280709
FFWARX
WIC123-280845-
/O.EXT.KARX.FF.W.0010.000000T0000Z-210828T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
209 AM CDT Sat Aug 28 2021

The National Weather Service in La Crosse has extended the

* Flash Flood Warning for...
  Western Vernon County in southwestern Wisconsin...

* Until 345 AM CDT.

* At 209 AM CDT, local law enforcement reported flash flooding 
  across the warned area. Between 2 and 4 inches of rain have 
  fallen. Additional rainfall amounts up to a half inch are possible 
  in the warned area. Flash flooding is already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Law enforcement 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...
  Viroqua, Westby, Stoddard, Coon Valley, Springville, and Liberty.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4372 9119 4372 9075 4342 9072 4342 9074
      4349 9121 4351 9122 4357 9123 4358 9123
      4359 9123 4359 9124 4364 9125

FLASH FLOOD...OBSERVED

$$

KDS

865 
WGUS73 KARX 280844
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
344 AM CDT Sat Aug 28 2021

WIC123-280854-
/O.EXP.KARX.FF.W.0010.000000T0000Z-210828T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Vernon WI-
344 AM CDT Sat Aug 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 345 AM CDT EARLY THIS MORNING 
FOR WESTERN VERNON COUNTY...

The heavy rain has ended. Please continue to heed remaining road 
closures.

A Flash Flood Watch remains in effect until 900 AM CDT for portions 
of Iowa, southeast Minnesota and southwest Wisconsin.

LAT...LON 4372 9119 4372 9075 4342 9072 4342 9074
      4349 9121 4351 9122 4357 9123 4358 9123
      4359 9123 4359 9124 4364 9125

$$

DTJ

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 27, 7:38 PM CDT	Flash Flood Watch	ARX	Crawford, Richland, Vernon	18 hr
Aug 27, 8:03 PM CDT	Severe Thunderstorm Warning	ARX	Crawford, Grant	42 min
Aug 27, 8:48 PM CDT	Severe Thunderstorm Warning	ARX	Grant	42 min
Aug 27, 8:59 PM CDT	Tornado Warning	ARX	Grant	31 min
Aug 27, 11:24 PM CDT	Special Weather Statement	ARX	Vernon	36 min
Aug 27, 11:31 PM CDT	Severe Thunderstorm Warning	ARX	Richland, Vernon	59 min
Aug 27, 11:53 PM CDT	Severe Thunderstorm Warning	ARX	Richland	37 min
Aug 28, 1:40 AM CDT	Severe Thunderstorm Warning	ARX	Crawford, Richland	49 min
Aug 28, 3:15 AM CDT	River Flood Warning	ARX	La Crosse, Trempealeau	5 days
Aug 28, 4:14 AM CDT	River Flood Warning	ARX	Vernon	31 hr
Aug 28, 10:24 AM CDT	River Flood Warning	ARX	Crawford	4 days
Aug 28, 10:38 AM CDT	River Flood Watch	ARX	Juneau	22 hr
Aug 28, 10:46 AM CDT	River Flood Watch	ARX	Crawford	23 hr

Nearby

Flash Flood Warnings in Wisconsin, 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.