Alert archive / Iowa / Flash Flood Warnings in 2012

Flash Flood Warning 1, NWS Des Moines, IA

April 14, 2012Cass County, Iowa

NWS Des Moines, IA issued this flash flood warning at Apr 14, 2012, 6:59 PM CDT for Cass 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
Apr 14, 2012, 6:59 PM CDT (23:59 UTC)
Expired
Apr 14, 2012, 10:00 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

County Cass County, IA

The radar

The Omaha radar (KOAX), 112 km from the middle of the area, began a volume at 00:02 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, 12.0 hours before the alert went out and 112 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 2012-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2012-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1847 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
89 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.

906 
WGUS53 KDMX 142359
FFWDMX
IAC029-150300-
/O.NEW.KDMX.FF.W.0001.120414T2359Z-120415T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
659 PM CDT SAT APR 14 2012

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN CASS COUNTY IN SOUTHWEST IOWA...

* UNTIL 1000 PM CDT

* AT 658 PM CDT...LAW ENFORCEMENT REPORTED FLASH FLOODING IN 
ATLANTIC. THE FLASH FLOODING WAS CAUSED BY THUNDERSTORMS PRODUCING 
VERY HEAVY RAIN.  THE STORMS HAD MOVED OUT OF THE WARNED AREA BUT 
ADDITIONAL THUNDERSTORMS ARE POSSIBLE. 

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...ATLANTIC.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

&&

LAT...LON 4150 9487 4130 9497 4129 9515 4148 9516
      4149 9516

$$

JOHNSON
1 follow-up statement
781 
WGUS73 KDMX 150050
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
750 PM CDT SAT APR 14 2012

IAC029-150300-
/O.CON.KDMX.FF.W.0001.000000T0000Z-120415T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
750 PM CDT SAT APR 14 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 1000 PM CDT...

AT 749 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH 
FLOODING WAS CONTINUING IN ATLANTIC. THERE HAD ALSO BEEN FLASH 
FLOODING IN THE COUNTY AND IN GRISWOLD.  WATER LEVELS WERE 
RECEDING.  

ADDITIONAL THUNDERSTORMS ARE EXPECTED...BUT THERE WERE NO 
THUNDERSTORMS IN THE IMMEDIATELY UPSTREAM. 

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

SOME LOCATIONS THAT HAVE EXPERIENCED FLASH FLOODING 
INCLUDE...ATLANTIC.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE MINOR FLOODING OF
SMALL CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND
UNDERPASSES AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

&&

LAT...LON 4150 9487 4130 9497 4129 9515 4148 9516
      4149 9516

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 14, 3:53 AM CDTDense Fog AdvisoryDMXAdair, Adams, Audubon, Boone, Calhoun, Carroll and 22 more5 hr
Apr 14, 2:41 PM CDTSevere Thunderstorm WarningDMXAdair, Adams, Cass49 min
Apr 14, 3:47 PM CDTTornado WarningDMXAdair, Adams, Madison, Union28 min
Apr 14, 3:54 PM CDTSevere Thunderstorm WarningDMXAdair, Madison36 min
Apr 14, 4:27 PM CDTSevere Thunderstorm WarningDMXMadison, Warren48 min
Apr 14, 5:07 PM CDTSevere Thunderstorm WarningDMXPolk, Warren38 min
Apr 14, 5:45 PM CDTSevere Thunderstorm WarningDMXJasper, Polk45 min
Apr 14, 6:12 PM CDTSevere Thunderstorm WarningDMXAdair, Adams, Cass48 min
Apr 14, 6:26 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Ringgold, Union34 min
Apr 14, 6:27 PM CDTSevere Thunderstorm WarningDMXTaylor33 min
Apr 14, 6:48 PM CDTSevere Thunderstorm WarningDMXAdams, Clarke, Decatur, Madison, Ringgold, Taylor and 1 more42 min
Apr 14, 6:50 PM CDTSevere Thunderstorm WarningDMXPolk, Warren34 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.