Alert archive / Iowa / Flash Flood Warnings in 2014

Flash Flood Warning 33, NWS Sioux Falls, SD

June 26, 2014Lyon County, O'Brien County, Sioux County, Iowa

NWS Sioux Falls, SD issued this flash flood warning at Jun 26, 2014, 5:37 PM CDT for Lyon County, O'Brien County, Sioux County, Iowa. It was in force for 3 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
Jun 26, 2014, 5:37 PM CDT (22:37 UTC)
Expired
Jun 26, 2014, 8:30 PM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

Counties Lyon County, IA, O'Brien County, IA, Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 80 km from the middle of the area, began a volume at 22:37 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

TimeReportWhereRemark
Jun 26, 5:50 PM CDTFLASH FLOOD2 E Boyden, IAWATER RUNNING OVER HIGHWAY 18 EAST OF BOYDEN.
Jun 26, 5:50 PM CDTFLASH FLOODBoyden, IASEVERAL STREET INUNDATED WITH UP TO A FOOT OF WATER AROUND TOWN.
Jun 26, 6:20 PM CDTHEAVY RAIN 6.75Boyden, IARAINFALL AMOUNT FELL IN ABOUT 3 HOURS.
Jun 26, 8:30 PM CDTFLASH FLOODBoyden, IAWATER CONTINUES OVER HIGHWAY 18 AT BOYDEN.

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 12:00Z, 10.6 hours before the alert went out and 208 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 12:00Z on 2014-06-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1326 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 12:00Z on 2014-06-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 square meters per square second.1939Sfc1 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
1326 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
1035 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

342 
WGUS53 KFSD 262237
FFWFSD
IAC119-141-167-270130-
/O.NEW.KFSD.FF.W.0033.140626T2237Z-140627T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
537 PM CDT THU JUN 26 2014

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN SIOUX COUNTY IN NORTHWEST IOWA
  NORTHWESTERN O'BRIEN COUNTY IN NORTHWEST IOWA
  SOUTHEASTERN LYON COUNTY IN NORTHWEST IOWA

* UNTIL 830 PM CDT

* AT 533 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED   
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. 
NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATES TWO TO THREE INCHES 
OF RAINFALL OVER THE WARNED AREA.  THUNDERSTORMS CONTINUE TO 
BACKBUILD ACROSS THE SAME AREA...CREATING THE POTENTIAL FOR 
ADDITIONAL HEAVY RAIN ACROSS THE AREA. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  BOYDEN...HOSPERS...MATLOCK AND SHELDON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

&&

LAT...LON 4301 9585 4301 9610 4330 9613 4330 9586
      4326 9587 4325 9582

$$

BT
1 follow-up statement
884 
WGUS73 KFSD 262257
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
557 PM CDT THU JUN 26 2014

IAC119-141-167-270130-
/O.CON.KFSD.FF.W.0033.000000T0000Z-140627T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SIOUX IA-O'BRIEN IA-LYON IA-
557 PM CDT THU JUN 26 2014

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHEASTERN LYON...
NORTHWESTERN O'BRIEN AND NORTHEASTERN SIOUX COUNTIES UNTIL 830 PM
CDT...

AT 550 PM CDT...WEATHER SPOTTERS REPORTED THUNDERSTORMS WITH VERY 
HEAVY RAINFALL ACROSS THE WARNED AREA. DOPPLER RADAR ESTIMATED THREE 
TO FOUR INCHES OF RAIN NEAR BOYDEN.  SIOUX COUNTY EMERGENCY MANAGERS 
REPORTED WATER OVER HIGHWAY 18 NEAR BOYDEN. 

SLOW MOVING THUNDERSTORMS ARE PRODUCING VERY HEAVY RAINFALL IN THE
WARNED AREA. RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH
FLOODING TO OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING
INCLUDE...BOYDEN...HOSPERS...MATLOCK AND SHELDON.

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 4301 9585 4301 9610 4330 9613 4330 9586
      4326 9587 4325 9582

$$

BT

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 26, 3:46 PM CDTSevere Thunderstorm WarningFSDLyon, O'Brien, Osceola, Sioux33 min
Jun 26, 5:34 PM CDTSevere Thunderstorm WarningFSDO'Brien, Sioux41 min
Jun 26, 5:41 PM CDTFlash Flood WarningFSDWoodbury3 hr
Jun 26, 6:08 PM CDTSevere Thunderstorm WarningFSDO'Brien, Sioux23 min

Nearby

Flash Flood Warnings in Iowa, 2014Every flash flood warning in 2014

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.