Alert archive / South Dakota / Flash Flood Warnings in 2012

Flash Flood Warning 14, NWS Sioux Falls, SD

May 27, 2012Dixon County, Nebraska; Clay County, Union County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at May 27, 2012, 9:32 PM CDT for Dixon County, Nebraska; Clay County, Union County, South Dakota. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 27, 2012, 9:32 PM CDT (02:32 UTC)
Expired
May 28, 2012, 1:58 AM CDT
In force
4 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

Counties Dixon County, NE, Clay County, SD, Union County, SD

The radar

The Sioux Falls radar (KFSD), 118 km from the middle of the area, began a volume at 02:34 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.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.5 hours before the alert went out and 141 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-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2012-05-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 849 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2012-05-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
849 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
2094 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

074 
WGUS53 KFSD 280232
FFWFSD
NEC051-SDC027-127-280830-
/O.NEW.KFSD.FF.W.0014.120528T0232Z-120528T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
932 PM CDT SUN MAY 27 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL UNION COUNTY IN SOUTHEAST SOUTH DAKOTA
  DIXON COUNTY IN NORTHEAST NEBRASKA
  SOUTHEASTERN CLAY COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 330 AM CDT

* AT 925 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED     
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. AN 
  ESTIMATED 3 INCHES OF RAIN HAS FALLEN NEAR MASKELL AND ROAD 
  FLOODING HAS BEEN REPORTED. AN ADDITIONAL INCH OF RAINFALL IS 
  POSSIBLE THIS EVENING. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PONCA...VERMILLION...ALLEN...CONCORD...DIXON...ELK POINT...
  MARTINSBURG...MASKELL AND NEWCASTLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4227 9703 4276 9703 4283 9698 4274 9663
      4271 9663 4269 9659 4226 9697 4226 9701

$$

HANKO
2 follow-up statements
620 
WGUS53 KFSD 280328
FFWFSD
NEC051-SDC027-127-280930-
/O.EXT.KFSD.FF.W.0014.000000T0000Z-120528T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1028 PM CDT SUN MAY 27 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  CENTRAL UNION COUNTY IN SOUTHEAST SOUTH DAKOTA
  DIXON COUNTY IN NORTHEAST NEBRASKA
  SOUTHEASTERN CLAY COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 430 AM CDT MONDAY

* AT 1025 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED   
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. RADAR 
INDICATES FOUR TO FIVE INCHES OF RAIN HAS FALLEN OVER THE WARNED 
AREA.  AN ADDITIONAL HALF OF AN INCH TO AN INCH OF RAIN IS EXPECTED 
OVER THE NEXT FEW HOURS. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PONCA...VERMILLION...ALLEN...CONCORD...DIXON...ELK POINT...
  MARTINSBURG...MASKELL AND NEWCASTLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. DO
NOT ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND TO
ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN
WATER BEGINS RISING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4227 9703 4276 9703 4283 9698 4274 9663
      4271 9663 4269 9659 4226 9697 4226 9701

$$

BT
480 
WGUS73 KFSD 280658
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
158 AM CDT MON MAY 28 2012

NEC051-SDC027-127-280712-
/O.CAN.KFSD.FF.W.0014.000000T0000Z-120528T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DIXON NE-CLAY SD-UNION SD-
158 AM CDT MON MAY 28 2012

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR CENTRAL UNION...
SOUTHEASTERN CLAY AND DIXON COUNTIES IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA HAVE RECEDED OR WERE BEGINNING TO 
RECEDE...ENDING THE FLOOD THREAT.

IF FLOODING WAS OBSERVED PLEASE RELAY YOUR REPORT TO LOCAL LAW
ENFORCEMENT OR TO THE NATIONAL WEATHER SERVICE IN SIOUX FALLS.

LAT...LON 4227 9703 4276 9703 4283 9698 4274 9663
      4271 9663 4269 9659 4226 9697 4226 9701

$$

CHENARD

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 27, 9:18 PM CDTSevere Thunderstorm WarningFSDDakota, Dixon27 min
May 27, 7:11 PM CDTSevere Thunderstorm WarningFSDLincoln, Union34 min
May 27, 7:22 PM CDTFlash Flood WarningFSDClay, Lincoln, Union7 hr
May 27, 7:31 PM CDTSevere Thunderstorm WarningFSDLincoln29 min
May 27, 9:42 PM CDTSevere Thunderstorm WarningFSDUnion10 min

Nearby

Flash Flood Warnings in South Dakota, 2012Flash Flood Warnings in Nebraska, 2012Every flash flood warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.