Alert archive / Iowa / Flash Flood Warnings in 2012

Flash Flood Warning 7, NWS Des Moines, IA

May 4, 2012Mahaska County, Poweshiek County, Iowa

NWS Des Moines, IA issued this flash flood warning at May 4, 2012, 5:44 AM CDT for Mahaska County, Poweshiek County, Iowa. 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 4, 2012, 5:44 AM CDT (10:44 UTC)
Expired
May 4, 2012, 10:11 AM CDT
In force
4 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

Counties Mahaska County, IA, Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 114 km from the middle of the area, began a volume at 10:44 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

Davenport, (KDVN), launched 00:00Z, 10.7 hours before the alert went out and 156 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, Davenport, at 00:00Z on 2012-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1056 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, Davenport, at 00:00Z on 2012-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.193958Sfc1 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
1056 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
1420 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
100 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.7

Open this sounding in Storm Lab

The text

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

016 
WGUS53 KDMX 041044
FFWDMX
IAC123-157-041630-
/O.NEW.KDMX.FF.W.0007.120504T1044Z-120504T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
544 AM CDT FRI MAY 4 2012

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN MAHASKA COUNTY IN SOUTH CENTRAL IOWA...
  SOUTHEASTERN POWESHIEK COUNTY IN CENTRAL IOWA...

* UNTIL 1130 AM CDT

* AT 542 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE 
  WARNED AREA. AS MUCH AS 1.75 TO 2.5 INCHES OF RAIN HAS FALLEN OVER 
  THE PAST HOUR. AN ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED TO 
  FALL.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO   
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE BUT 
  ARE NOT LIMITED TO THE DEEP RIVER AREA.

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. TURN AROUND...DONT DROWN.

&&

LAT...LON 4150 9230 4150 9240 4137 9241 4137 9242
      4162 9260 4168 9246 4166 9230 4163 9229
      4151 9229

$$

ZOGG
3 follow-up statements
108 
WGUS73 KDMX 041140
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
640 AM CDT FRI MAY 4 2012

IAC123-157-041630-
/O.CON.KDMX.FF.W.0007.000000T0000Z-120504T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POWESHIEK IA-MAHASKA IA-
640 AM CDT FRI MAY 4 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHEASTERN MAHASKA AND
SOUTHEASTERN POWESHIEK COUNTIES UNTIL 1130 AM CDT...

AT 634 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL CONTINUED ACROSS 
PORTIONS OF THE WARNED AREA. AN ESTIMATED TWO TO THREE INCHES OF 
RAIN HAS FALLEN ACROSS THE WARNED AREA IN THE LAST THREE HOURS AND 
AN ADDITIONAL INCH OR MORE IS POSSIBLE AS NEW STORMS DEVELOP THIS 
MORNING.

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

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 4150 9230 4150 9240 4137 9241 4137 9242
      4162 9260 4168 9246 4166 9230 4163 9229
      4151 9229

$$

SKOW
868 
WGUS73 KDMX 041332
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
832 AM CDT FRI MAY 4 2012

IAC123-157-041630-
/O.CON.KDMX.FF.W.0007.000000T0000Z-120504T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POWESHIEK IA-MAHASKA IA-
832 AM CDT FRI MAY 4 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHEASTERN MAHASKA AND
SOUTHEASTERN POWESHIEK COUNTIES UNTIL 1130 AM CDT...

WHILE THUNDERSTORMS HAVE ENDED ACROSS THE WARNED AREA...A FEW RURAL 
ROADS MAY STILL BE FLOODED OR WASHED OUT DUE TO THE HEAVY RAINS FROM 
THIS MORNING. IF YOU ENCOUNTER A WASHED OUT ROAD...TRY TO FIND AN 
ALTERNATIVE ROUTE SINCE THE ROAD MAY NOT BE SAFE TO DRIVE ON. PLEASE 
REPORT ANY FLOODING OR FLOOD DAMAGE TO LOCAL LAW ENFORCEMENT OR THE 
NATIONAL WEATHER SERVICE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 4149 9248 4159 9244 4162 9239 4162 9230
      4151 9229 4150 9230 4150 9240 4137 9241
      4137 9242

$$

SKOW
477 
WGUS73 KDMX 041511
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1011 AM CDT FRI MAY 4 2012

IAC123-157-041525-
/O.CAN.KDMX.FF.W.0007.000000T0000Z-120504T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POWESHIEK IA-MAHASKA IA-
1011 AM CDT FRI MAY 4 2012

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR NORTHEASTERN
MAHASKA AND SOUTHEASTERN POWESHIEK COUNTIES IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA ARE BEGINNING TO RECEDE...AND 
ADDITIONAL FLOODING IS NOT ANTICIPATED. IF FLOODING HAS BEEN 
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4149 9248 4159 9244 4162 9239 4162 9230
      4151 9229 4150 9230 4150 9240 4137 9241
      4137 9242

$$

SKOW

The office that day

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

IssuedProductOfficeCountiesLasted
May 3, 7:41 PM CDTSevere Thunderstorm WarningDMXHumboldt28 min
May 3, 11:32 PM CDTFlash Flood WatchDMXAdams, Appanoose, Clarke, Davis, Decatur, Lucas and 8 more9 hr
May 4, 2:09 AM CDTSevere Thunderstorm WarningDMXAdams, Union51 min
May 4, 2:13 AM CDTSevere Thunderstorm WarningDMXRinggold, Taylor32 min
May 4, 2:45 AM CDTSevere Thunderstorm WarningDMXRinggold, Taylor45 min
May 4, 2:54 AM CDTSevere Thunderstorm WarningDMXAdams51 min
May 4, 3:27 AM CDTSevere Thunderstorm WarningDMXTaylor48 min
May 4, 5:03 AM CDTSevere Thunderstorm WarningDMXLucas, Marion, Monroe42 min
May 4, 4:05 PM CDTSevere Thunderstorm WarningDMXEmmet, Kossuth55 min
May 4, 4:22 PM CDTSevere Thunderstorm WarningDMXEmmet, Palo Alto38 min
May 4, 4:40 PM CDTSevere Thunderstorm WarningDMXKossuth50 min
May 4, 4:46 PM CDTTornado WarningDMXPalo Alto29 min
May 4, 4:59 PM CDTSevere Thunderstorm WarningDMXEmmet, Kossuth, Palo Alto46 min
May 4, 5:26 PM CDTSevere Thunderstorm WarningDMXHancock, Winnebago49 min
May 4, 5:30 PM CDTSevere Thunderstorm WarningDMXKossuth17 min
May 4, 5:40 PM CDTTornado WarningDMXHancock, Humboldt, Kossuth, Wright35 min
May 4, 5:46 PM CDTSevere Thunderstorm WarningDMXKossuth15 min
May 4, 6:00 PM CDTSevere Thunderstorm WarningDMXCerro Gordo, Hancock, Winnebago, Worth60 min
May 4, 6:37 PM CDTSevere Thunderstorm WarningDMXHamilton, Webster, Wright23 min

Nearby

Flash Flood Warnings in Iowa, 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.