Alert archive / Iowa / Flash Flood Warnings in 2011

Flash Flood Warning 8, NWS Des Moines, IA

May 25, 2011Decatur County, Lucas County, Wayne County, Iowa

NWS Des Moines, IA issued this flash flood warning at May 25, 2011, 3:53 PM CDT for Decatur County, Lucas County, Wayne County, Iowa. It was in force for 3 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 25, 2011, 3:53 PM CDT (20:53 UTC)
Expired
May 25, 2011, 6:55 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

Counties Decatur County, IA, Lucas County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 109 km from the middle of the area, began a volume at 20:55 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 12:00Z, 8.9 hours before the alert went out and 238 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 2011-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 159 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 2011-05-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
159 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
565 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
-2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

993 
WGUS53 KDMX 252053
FFWDMX
IAC053-117-185-260300-
/O.NEW.KDMX.FF.W.0008.110525T2053Z-110526T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
353 PM CDT WED MAY 25 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR MINOR FLOODING OF POOR DRAINAGE AREAS IN...
  DECATUR COUNTY IN SOUTH CENTRAL IOWA...
  SOUTHERN LUCAS COUNTY IN SOUTH CENTRAL IOWA...
  WAYNE COUNTY IN SOUTH CENTRAL IOWA...

* UNTIL 1000 PM CDT

* AT 352 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE      
  WARNED AREA. DOPPLER RADAR INDICATES 1 TO 2 INCHES OF RAIN HAS     
  OCCURRED IN PARTS OF THE AREA. 


* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  LAMONI...CORYDON...LEON AND SEYMOUR.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF AROUND AN INCH ARE POSSIBLE IN THE 
WARNED AREA.

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. TURN AROUND...DONT DROWN.

&&

LAT...LON 4057 9401 4076 9401 4090 9356 4111 9310
      4059 9309

$$
3 follow-up statements
866 
WGUS73 KDMX 252157
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
457 PM CDT WED MAY 25 2011

IAC053-117-185-260300-
/O.CON.KDMX.FF.W.0008.000000T0000Z-110526T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAYNE IA-LUCAS IA-DECATUR IA-
457 PM CDT WED MAY 25 2011

...FLASH FLOOD WARNING FOR MINOR FLOODING OF POOR DRAINAGE AREAS
REMAINS IN EFFECT FOR DECATUR...SOUTHERN LUCAS AND WAYNE COUNTIES
UNTIL 1000 PM CDT...

AT 453 PM CDT...WEATHER SPOTTERS REPORTED THUNDERSTORMS WITH VERY 
HEAVY RAINFALL ACROSS THE WARNED AREA. RAINFALL OF THREE QUARTERS TO 
ONE AND ONE HALF INCHES HAS BEEN REPORTED IN MANY PARTS OF THE AREA. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
LAMONI...CORYDON...LEON AND SEYMOUR.

SPOTTERS OVER CENTRAL AND NORTH CENTRAL SECTION OF WAYNE COUNTY 
REPORTED MINOR FLOODING.  DITCHES WERE FILLED WITH WATER AND 
CONSIDERABLE PONDING WAS REPORTED IN THE FARM FIELDS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE HEAVIEST STORMS HAVE MOVED NORTHWEST OF THE AREA.  SOME 
ADDITIONAL RAINFALL IS LIKELY...HOWEVER ADDITIONAL HEAVY RAINFALL IS 
NOW LIKELY.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR AND THE
WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. TURN
AROUND...DONT DROWN.

&&

LAT...LON 4057 9401 4076 9401 4090 9356 4111 9310
      4059 9309

$$
977 
WGUS73 KDMX 252256
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
556 PM CDT WED MAY 25 2011

IAC053-117-185-260300-
/O.CON.KDMX.FF.W.0008.000000T0000Z-110526T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAYNE IA-LUCAS IA-DECATUR IA-
556 PM CDT WED MAY 25 2011

...FLASH FLOOD WARNING FOR MINOR FLOODING OF POOR DRAINAGE AREAS
REMAINS IN EFFECT FOR DECATUR...SOUTHERN LUCAS AND WAYNE COUNTIES
UNTIL 1000 PM CDT...

AT 556 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL HAVE ENDED ACROSS THE WARNED 
AREA. HOWEVER...IT WILL TAKE TIME FOR THE EARLIER HEAVY RAINS TO 
DRAIN AND FOR CREEKS AND RIVERS TO RECEDE.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
LAMONI...CORYDON...LEON AND SEYMOUR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR AND THE
WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. TURN
AROUND...DONT DROWN.

&&

LAT...LON 4057 9401 4076 9401 4090 9356 4111 9310
      4059 9309

$$

LEE
701 
WGUS73 KDMX 252355
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
655 PM CDT WED MAY 25 2011

IAC053-117-185-260009-
/O.CAN.KDMX.FF.W.0008.000000T0000Z-110526T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAYNE IA-LUCAS IA-DECATUR IA-
655 PM CDT WED MAY 25 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR DECATUR...SOUTHERN
LUCAS AND WAYNE COUNTIES IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS LARGELY ENDED OVER THE WARNED 
AREA. STREAMS AND CREEKS IN THE WARNED AREA ARE BEGINNING TO SLOWLY 
RECEDE...BUT IT WILL TAKE SOME TIME FOR RESIDUAL FLOODING TO CEASE 
ESPECIALLY IN LOW LYING AREAS. IF FLOODING HAS BEEN 
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4057 9401 4076 9401 4090 9356 4111 9310
      4059 9309

$$

LEE

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 24, 9:45 PM CDTFlash Flood WatchDMXAdair, Adams, Appanoose, Cass, Clarke, Davis and 11 more24 hr
May 25, 12:38 AM CDTFlash Flood WarningDMXClarke, Union6 hr
May 25, 1:05 AM CDTRiver Flood WarningDMXDecatur57 hr
May 25, 4:22 AM CDTWind AdvisoryDMXAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more17 hr
May 25, 6:04 AM CDTRiver Flood WarningDMXMadison, Warren27 hr
May 25, 6:22 AM CDTRiver Flood WarningDMXMadison, Warren22 hr
May 25, 6:22 AM CDTRiver Flood WarningDMXWarren9 hr
May 25, 6:53 AM CDTRiver Flood WarningDMXAppanoose, Wayne30 hr
May 25, 7:25 AM CDTRiver Flood WarningDMXLucas, Wayne24 hr
May 25, 7:58 AM CDTRiver Flood WarningDMXWapello23 hr
May 25, 3:04 PM CDTRiver Flood WarningDMXBoone, Hamilton, Webster7 days
May 25, 3:18 PM CDTRiver Flood WarningDMXMahaska, Marion18 hr
May 25, 4:34 PM CDTFlash Flood WarningDMXAppanoose, Davis, Wapello4 hr

Nearby

Flash Flood Warnings in Iowa, 2011Every flash flood warning in 2011

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.