Alert archive / Iowa / Flash Flood Warnings in 2003

Flash Flood Warning 3, NWS Des Moines, IA

May 8, 2003Polk County, Story County, Iowa

NWS Des Moines, IA issued this flash flood warning at May 8, 2003, 8:46 PM CDT for Polk County, Story 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 8, 2003, 8:46 PM CDT (01:46 UTC)
Expired
May 9, 2003, 2:45 AM CDT
In force
6 hr
Issued by
NWS Des Moines, IA
Area
Counties, with a storm outline in the text

Counties Polk County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 18 km from the middle of the area, began a volume at 01:35 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, 1.8 hours before the alert went out and 242 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 2003-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 7 joules per kilogram.LCLEL10008507005003002001001 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 2003-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 571 square meters per square second.1939587897117Sfc1 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
7 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
453 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
571 m²/s²
0-3 km storm-relative helicity
807 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KDMX 090147
FFWDMX
IAC153-169-090745-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
846 PM CDT THU MAY 8 2003

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
  STORY COUNTY IN CENTRAL IOWA

* UNTIL 245 AM

* AT 845 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS WITH FLASH FLOOD PRODUCING RAINS IN THE WARNING AREA.

* THUNDERSTORMS ARE CONTINUOUSLY REDEVELOPING IN SOUTH CENTRAL INTO  
  SOUTHWEST IOWA RESULTING IN EXCESSIVE RAINFALL. RAINFALL RATES     
  WILL AVERAGE 1 INCH PER HALF HOUR. THIS WILL PRODUCE FLASH         
  FLOODING ALONG SMALL STREAMS AND CREEKS IN THE WARNING AREA

OTHER WARNING LOCATIONS INCLUDE...
ALLEMAN...ALTOONA...AMES...AMES MUNICIPAL AIRPORT...ANKENY...ANKENY
REGIONAL AIRPORT...BONDURANT...CAMBRIDGE...COLO...DES MOINES
MORNINGSTAR AIRPORT...ELKHART...GILBERT...HUXLEY...JOHNSTON...
KELLEY...MAXWELL...MCCALLSBURG...MITCHELLVILLE...NEVADA...PLEASANT
HILL...POLK CITY...ROLAND...SAYLORVILLE...SHELDAHL...SLATER...STORY
CITY...URBANDALE...WEST DES MOINES...WINDSOR HEIGHTS AND ZEARING

FLASH FLOODS OCCUR QUICKLY...MOVE TO HIGHER GROUND. AVOID WATER
COVERED ROADS...THE ROAD MAY BE WASHED OUT. LESS THAN ONE FOOT OF
FAST FLOWING WATER CAN SWEEP AN AUTOMOBILE OFF THE ROAD.

LAT...LON 4153 9378 4152 9335 4187 9335 4219 9325
          4221 9368

KULA

$$
4 follow-up statements
000 
WGUS73 KDMX 090247
FFSDMX
IAC153-169-090845-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
943 PM CDT THU MAY 8 2003

...A FLASH FLOOD WARNING CONTINUES FOR STORY AND POLK COUNTIES UNTIL
245 AM...

AT 943 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
NEWLY DEVELOPED THUNDERSTORMS FROM WINTERSET THROUGH OSCEOLA AND 
LAMONI MOVING NORTHEAST AT 45 MPH INTO THE WARNED AREA.  ADDITIONAL 
LOCAL RAINFALL OF ONE HALF TO ONE INCH IS LIKELY THROUGH 11 
PM...WITH THE POSSIBILITY OF ADDITIONAL STORMS MOVING IN THROUGH 
EARLY FRIDAY MORNING.  THIS WILL PRODUCE LOCALIZED URBAN FLASH 
FLOODING IN THE DES MOINES METRO...WITH QUICK RISES ON SMALLER 
CREEKS IN THE AREA. 

FLASH FLOODS OCCUR QUICKLY...MOVE TO HIGHER GROUND. AVOID WATER
COVERED ROADS...THE ROAD MAY BE WASHED OUT. LESS THAN ONE FOOT OF
FAST FLOWING WATER CAN SWEEP AN AUTOMOBILE OFF THE ROAD.

LAT...LON 4153 9378 4152 9337 4187 9336 4220 9324
          4219 9363

KULA

$$
000 
WGUS73 KDMX 090349
FFSDMX
IAC153-169-090845-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1049 PM CDT THU MAY 8 2003

...A FLASH FLOOD WARNING CONTINUES FOR STORY AND POLK COUNTIES UNTIL
245 AM...

AT 1040 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED ISOLATED 
THUNDERSTORMS CONTAINING HEAVY RAINFALL FROM DES MOINES INTO WESTERN 
AND SOUTHWESTERN IOWA. THE STORMS ARE MOVING NORTHEAST AT 45 MPH 
TOWARD THE WARNED AREA.  WIDESPREAD HEAVY RAINFALL IS NOT EXPECTED 
AND EARLIER RAINS WERE NOT SUFFICIENT TO CAUSE WIDESPREAD FLASH 
FLOODING.  HOWEVER...ADDITIONAL LOCAL RAINFALL OF ONE HALF TO ONE 
INCH IS POSSIBLE THROUGH MIDNIGHT SO THE FLASH FLOOD WARNING IS 
CONTINUED. ADDITIONAL RAINS WILL PRODUCE LOCALIZED URBAN 
FLOODING...WITH QUICK RISES ON SMALLER CREEKS IN THE AREA. 

FLASH FLOODS OCCUR QUICKLY. AVOID WATER COVERED ROADS...THE ROAD MAY 
BE WASHED OUT. LESS THAN ONE FOOT OF FAST FLOWING WATER CAN SWEEP AN 
AUTOMOBILE OFF THE ROAD.

LAT...LON 4153 9378 4152 9337 4187 9336 4220 9324
          4219 9363

KULA

$$
000 
WGUS73 KDMX 090448
FFSDMX
IAC153-169-090845-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1147 PM CDT THU MAY 8 2003

...A FLASH FLOOD WARNING CONTINUES FOR STORY AND POLK COUNTIES UNTIL
245 AM...

AT 1140 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED A NARROW 
BAND OF THUNDERSTORMS WITH HEAVY RAINFALL FROM WEST DES MOINES TO 
WEST OF WINTERSET.  THE STORMS ARE MOVING NORTHEAST AT 45 MPH AND 
SHOULD REACH A LINE FROM NEAR MARSHALLTOWN TO SOUTHEASTERN POLK 
COUNTY BY 1245 AM. RAINFALL COULD REACH A HALF INCH IN LESS THAN 30 
MINUTES...CAUSING STREET FLOODING AND SOME RISES IN SMALLER 
STREAMS. 

ONCE THE LINE OF STORMS PASSES THROUGH...THE THREAT FOR HEAVY RAIN 
SHOULD BE DIMINISHED AND THE FLASH FLOOD WARNING WILL LIKELY BE 
CANCELLED BY 100 AM. 

FLASH FLOODS OCCUR QUICKLY. AVOID WATER COVERED ROADS...THE ROAD MAY 
BE WASHED OUT. LESS THAN ONE FOOT OF FAST FLOWING WATER CAN SWEEP AN 
AUTOMOBILE OFF THE ROAD.

LAT...LON 4153 9378 4152 9337 4187 9336 4220 9324
          4219 9363

JUNGBLUTH

$$
000 
WGUS73 KDMX 090530
FFSDMX
IAC153-169-090545-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1230 AM CDT FRI MAY 9 2003

...THE FLASH FLOOD WARNING WHICH WAS IN EFFECT FOR STORY AND POLK 
COUNTIES HAS BEEN CANCELLED...

THE LAST ROUND OF STORMS HAS MOVED OUT OF THE WARNED AREA... 
PRODUCING AROUND ONE QUARTER OF AN INCH OF RAIN...THUS THE WARNING 
HAS BEEN CANCELLED.

AT 1225 AM...THE BACK EDGE OF THE THUNDERSTORMS EXTENDED FROM 
ZEARING TO 10 MILES NORTHEAST OF DES MOINES...OR FROM 45 MILES 
NORTHEAST OF DES MOINES TO 10 MILES NORTHEAST OF DES MOINES...MOVING 
NORTHEAST AT 55 MPH. NO ADDITIONAL DEVELOPMENT OF THUNDERSTORMS IS 
EXPECTED TONIGHT AND STREAMS SHOULD REMAIN IN THEIR BANKS.

LAT...LON 4221 9369 4187 9371 4154 9380 4153 9336
          4187 9335 4220 9326

JUNGBLUTH

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 8, 7:08 PM CDTSevere Thunderstorm WarningDMXMahaska37 min
May 8, 7:30 PM CDTSevere Thunderstorm WarningDMXPoweshiek30 min
May 8, 7:36 PM CDTSevere Thunderstorm WarningDMXPolk, Warren34 min
May 8, 7:41 PM CDTSevere Thunderstorm WarningDMXJasper, Marshall44 min
May 8, 7:44 PM CDTSevere Thunderstorm WarningDMXTama31 min
May 8, 7:50 PM CDTSevere Thunderstorm WarningDMXPolk25 min
May 8, 8:07 PM CDTSevere Thunderstorm WarningDMXStory23 min
May 8, 8:11 PM CDTSevere Thunderstorm WarningDMXBlack Hawk34 min
May 8, 8:32 PM CDTSevere Thunderstorm WarningDMXBremer28 min
May 8, 8:53 PM CDTSevere Thunderstorm WarningDMXTaylor37 min
May 8, 9:11 PM CDTSevere Thunderstorm WarningDMXRinggold34 min

Nearby

Flash Flood Warnings in Iowa, 2003Every flash flood warning in 2003

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.