Alert archive / Iowa / Flash Flood Warnings in 2002

Flash Flood Warning 3, NWS Des Moines, IA

June 12, 2002Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jun 12, 2002, 5:50 PM CDT for Polk 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
Jun 12, 2002, 5:50 PM CDT (22:50 UTC)
Expired
Jun 12, 2002, 11:45 PM CDT
In force
6 hr
Issued by
NWS Des Moines, IA
Area
Counties, with a storm outline in the text

County Polk County, IA

The radar

The Des Moines radar (KDMX), 18 km from the middle of the area, began a volume at 22:52 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, 10.8 hours before the alert went out and 240 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 2002-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2034 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 2002-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 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
2034 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
700 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
61 m²/s²
Significant tornado parameter
-0.5
Supercell composite
-2.4

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KDMX 122251
FFWDSM
IAC153-130445-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
550 PM CDT WED JUN 12 2002

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  POLK COUNTY IN CENTRAL IOWA
  THIS INCLUDES THE CITY OF DES MOINES

* UNTIL 1145 PM

* AT 542 PM...THE PUBLIC REPORTED THUNDERSTORMS WITH FLASH FLOOD
  PRODUCING RAINS IN THE WARNING AREA.

* SLOW MOVING THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL WILL       
  CONTINUE OVER THE NEXT 2 HOURS. RAINFALL RATES WILL 1 TO 2 INCHES  
  PER HOUR.  THIS WILL PRODUCE FLASH FLOODING IN THE DES MOINES      
  METRO AREA...PARTICULARLY IN LOW LYING AREAS.

LAW ENFORCEMENT REPORTS STREET FLOODING ON FLEUR AND MERLE HAY ROADS.

OTHER WARNING LOCATIONS INCLUDE...
ALTOONA...ANKENY...BONDURANT...CLIVE...GRIMES...JOHNSTON...
MITCHELLVILLE...PLEASANT HILL...POLK CITY...SAYLORVILLE...
URBANDALE...WEST DES MOINES AND WINDSOR HEIGHTS

FLASH FLOODS OCCUR QUICKLY...MOVE TO HIGHER GROUND. NEVER DRIVE
THROUGH WATER OF UNKNOWN DEPTH...THE ROAD SURFACE MAY BE WASHED OUT.
LESS THAN ONE FOOT OF FAST FLOWING WATER CAN SWEEP AN AUTOMOBILE OFF
THE ROAD.

LAT...LON 4177 9335 4151 9334 4152 9379 4178 9381

KULA

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 12, 3:34 PM CDTSevere Thunderstorm WarningDMXMadison41 min
Jun 12, 4:15 PM CDTSevere Thunderstorm WarningDMXClarke, Madison45 min
Jun 12, 4:29 PM CDTSevere Thunderstorm WarningDMXWarren31 min
Jun 12, 4:58 PM CDTSevere Thunderstorm WarningDMXPolk32 min
Jun 12, 5:13 PM CDTSevere Thunderstorm WarningDMXPolk, Warren47 min
Jun 12, 5:50 PM CDTSevere Thunderstorm WarningDMXDallas40 min
Jun 12, 5:54 PM CDTSevere Thunderstorm WarningDMXDavis36 min
Jun 12, 6:14 PM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 12, 6:35 PM CDTFlash Flood WarningDMXDallas3 hr

Nearby

Flash Flood Warnings in Iowa, 2002Every flash flood warning in 2002

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.