Alert archive / Iowa / Flash Flood Warnings in 2011

Flash Flood Warning 7, NWS Des Moines, IA

May 25, 2011Clarke County, Union County, Iowa

NWS Des Moines, IA issued this flash flood warning at May 25, 2011, 12:38 AM CDT for Clarke County, Union County, Iowa. It was in force for 6 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, 12:38 AM CDT (05:38 UTC)
Expired
May 25, 2011, 6:30 AM CDT
In force
6 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

Counties Clarke County, IA, Union County, IA

The radar

The Des Moines radar (KDMX), 86 km from the middle of the area, began a volume at 05:39 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, 5.6 hours before the alert went out and 189 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 2011-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 208 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 2011-05-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 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
208 J/kg
Mixed-layer CIN
-192 J/kg
Mixed-layer LCL
889 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

312 
WGUS53 KDMX 250538
FFWDMX
IAC039-175-251130-
/O.NEW.KDMX.FF.W.0007.110525T0538Z-110525T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1238 AM CDT WED MAY 25 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLARKE COUNTY IN SOUTH CENTRAL IOWA...
  UNION COUNTY IN SOUTH CENTRAL IOWA...

* UNTIL 630 AM CDT

* AT 1237 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE      
  WARNED AREA. RAINFALL RATES OF UP TO AN INCH IN A 15 TO 20 MINUTE  
  PERIOD HAVE OCCURRED IN UNION COUNTY WITH ADDITIONAL THUNDERSTORMS 
  MOVING INTO THE AREA.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  CRESTON AND OSCEOLA.


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.

&&

LAT...LON 4106 9448 4116 9413 4116 9355 4096 9356
      4090 9433 4090 9447

$$
4 follow-up statements
992 
WGUS73 KDMX 250640
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
140 AM CDT WED MAY 25 2011

IAC039-175-251130-
/O.CON.KDMX.FF.W.0007.000000T0000Z-110525T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
UNION IA-CLARKE IA-
140 AM CDT WED MAY 25 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CLARKE AND UNION
COUNTIES UNTIL 630 AM CDT...

AT 138 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. 
DOPPLER RADAR INDICATED THAT PART OF THE WARNED AREA HAVE RECEIVED 2 
TO 3 INCHES OF RAINFALL.  OBSERVATIONS INDICATED THAT OVER 1.5 
INCHES OF THIS FELL IN UNDER AN HOUR.  THE HEAVY THUNDERSTORMS HAVE 
MOVED NORTHEAST OF THE AREA...HOWEVER ADDITIONAL LIGHTER RAINFALL IS 
EXPECTED THROUGH THE BALANCE OF THE MORNING.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
CRESTON AND OSCEOLA.

LAW ENFORCEMENT REPORTED THAT ONLY URBAN FLOODING HAS OCCURRED THUS 
FAR WITH TYPICAL LOW SPOTS BEING FLOODED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4106 9448 4116 9413 4116 9355 4096 9356
      4090 9433 4090 9447

$$
749 
WGUS73 KDMX 250728
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
228 AM CDT WED MAY 25 2011

IAC039-175-251130-
/O.CON.KDMX.FF.W.0007.000000T0000Z-110525T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
UNION IA-CLARKE IA-
228 AM CDT WED MAY 25 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CLARKE AND UNION
COUNTIES UNTIL 630 AM CDT...

AT 226 AM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL MOVED ACROSS THE AREA.  SO 
FAR...FLOODING HAS BEEN RESTRICTED TO LOW CROSSING AREAS AND URBAN 
ROADWAYS.  

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
CRESTON AND OSCEOLA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE HEAVY STORMS HAVE MOVED TO THE NORTHEAST OF THE AREA.  
ADDITIONAL RAINFALL AMOUNTS OF UP TO ONE HALF INCH ARE EXPECTED 
THROUGH THE REST OF THE NIGHT IN THE WARNED AREA.

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

&&

LAT...LON 4106 9448 4116 9413 4116 9355 4096 9356
      4090 9433 4090 9447

$$
391 
WGUS73 KDMX 251010
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
510 AM CDT WED MAY 25 2011

IAC039-175-251130-
/O.CON.KDMX.FF.W.0007.000000T0000Z-110525T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
UNION IA-CLARKE IA-
510 AM CDT WED MAY 25 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CLARKE AND UNION
COUNTIES UNTIL 630 AM CDT...

AT 507 AM CDT...THUNDERSTORMS WITH VERY HEAVY RAINFALL MOVED ACROSS 
THE AREA OVERNIGHT HOWEVER THE HEAVY RAINFALL HAS ENDED.  THUS 
FAR...FLOODING HAS BEEN RESTRICTED TO LOW CROSSING AREAS AND URBAN 
ROADWAYS. DAYLIGHT THIS MORNING MAY REVEAL ADDITIONAL PROBLEM AREAS.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
CRESTON AND OSCEOLA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4106 9448 4116 9413 4116 9355 4096 9356
      4090 9433 4090 9447

$$

DONAVON
404 
WGUS73 KDMX 251129
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
629 AM CDT WED MAY 25 2011

IAC039-175-251144-
/O.EXP.KDMX.FF.W.0007.000000T0000Z-110525T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
UNION IA-CLARKE IA-
629 AM CDT WED MAY 25 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR CLARKE AND UNION
COUNTIES WILL BE ALLOWED TO EXPIRE AT 630 AM CDT...

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 HAS BEEN OBSERVED...
PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4106 9448 4116 9413 4116 9355 4096 9356
      4090 9433 4090 9447

$$

DONAVON

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, 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, 3:53 PM CDTFlash Flood WarningDMXDecatur, Lucas, Wayne3 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.