Alert archive / Iowa / Flash Flood Warnings in 1993

Flash Flood Warning 99, NWS Des Moines, IA

August 11, 1993Polk County, Warren County, Iowa

NWS Des Moines, IA issued this flash flood warning at Aug 11, 1993, 7:31 PM CDT for Polk County, Warren County, Iowa. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Aug 11, 1993, 7:31 PM CDT (00:31 UTC)
Expired
Aug 11, 1993, 10:30 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Polk County, IA, Warren County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.5 hours before the alert went out and 235 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 1993-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 613 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 1993-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 square meters per square second.1939Sfc1 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
613 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
872 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.3
Supercell composite
4.4

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KALO 120032
FFWDSM
IAC153-181-120330-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
ISSUED BY WATERLOO IA
731 PM CDT WED AUG 11 1993
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL 1030 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN CENTRAL IOWA
 
   ...POLK COUNTY
 
IN SOUTH CENTRAL IOWA
 
   ...WARREN COUNTY
 
AT 730 PM...STRONG THUNDERSTORMS PRODUCING VERY HEAVY RAINS CONTINUED IN
POLK AND WARREN COUNTIES. FLASH FLOODING IS OCCURING WITH THESE STORMS
AND PERSONS IN THE WARNED AREA SHOULD NOT ATTEMPT TO DRIVE THROUGH WATER
ON STREETS AND SHOULD STAY AWAY FROM CREEKS AND STREAMS.
 
 
 
DO NOT ATTEMPT TO DRIVE THROUGH RISING FLOOD WATERS.  IF YOU ARE
CAUGHT IN YOUR VEHICLE IN RISING FLOOD WATERS...ABANDON IT
IMMEDIATELY AND MOVE TO HIGHER GROUND.
 
 
 
LINDENBERG

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Aug 11, 5:49 PM CDT, 1 hour 42 minutes before
IAZALL-112340-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
549 PM CDT WED AUG 11 1993

AT 530 PM CDT...INTENSE THUNDERSTORMS CONTINUED OVER PORTIONS OF WEST
CENTRAL IOWA. THE STORMS WERE IN 45 MILE WIDE BAND EXTENDING FROM
COUNCIL BLUFFS TO 25 MILES WEST OF DES MOINES...NEAR REDFIELD. THE
HEAVIEST STORMS IN THIS BAND WERE LOCATED 45 MILES WEST OF DES MOINES
NEAR ADAIR AND NEAR REDFIELD. THESE STORMS WERE CABABLE OF PRODUCING
HEAVY RAIN...FREQUENT LIGHTNING...SMALL HAIL AND GUSTY WINDS. PERSONS IN
THE PATH OF THESE STORMS SHOULD SEEK SHELTER IMMEDIATELY.

THESE STORMS WERE PART OF A LARGER AREA OF SHOWERS AND THUNDERSTORMS
WHICH COVERED MUCH OF SOUTH CENTRAL AND SOUTHWEST IOWA SOUTH AND
WEST OF A LINE WHICH EXTENDED FROM 45 MILES SOUTHEAST OF SIOUX
CITY...NEAR ONAWA TO AMES TO OTTUMWA.

MOVEMENT OF ALL PRECIPITATION WAS NORTHEAST AT 25 MILES AN HOUR.

PETERSEN
Special weather statement, Aug 11, 5:50 PM CDT, 1 hour 41 minutes before
IAZALL-120130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
550 PM CDT WED AUG 11 1993

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL BE MOVING ACROSS CENTRAL
IOWA THIS EVENING...

STRONG THUNDERSTORMS...CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A
SHORT PERIOD OF TIME WILL BE TRACKING ACROSS CENTRAL IOWA...INCLUDING
THE DES MOINES METRO AREA BETWEEN 6 AND 8 PM THIS WEDNESDAY EVENING.
AS THE STORMS MOVED ACROSS GUTHRIE COUNTY IS WEST CENTRAL IOWA...NEARLY
A FOOT OF WATER WAS OVER HIGHWAY 295 NEAR THE TOWN OF MENLOW...OR ABOUT
40 MILES WEST OF DES MOINES. IN ADDITION...NEARLY 3 INCHES OF RAIN FELL
IN A LITTLE OVER AN HOUR AND A HALF IN THE TOWN OF ANITA IN CASS COUNTY
...OR 60 MILES WEST OF DES MOINES.

THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 25 MILES AN HOUR
WITH ADDITIONAL DEVELOPMENT OCCURRING TO THE WEST OF THIS AREA. RAINFALL
AMOUNTS MAY EXCEED 3 INCHES IN ISOLATED AREAS OF CENTRAL IOWA AS THE
THUNDERSTORMS MOVE ACROSS THE AREA THIS EVENING.

IF YOU SEE WATER OVER A ROADWAY...DO NOT ATTEMPT TO DRIVE THROUGH IT.
IF YOU LIVE NEAR A FLOOD PRONE CREEK OR STREAM...BE PREPARED TO MOVE
TO A PLACE OF SAFETY.

SMITH
Special weather statement, Aug 11, 5:55 PM CDT, 1 hour 36 minutes before
IAZALL-120130-

SPECIAL WEATHER STATEMENT...SPELLING CORRECTION
NATIONAL WEATHER SERVICE DES MOINES IA
555 PM CDT WED AUG 11 1993

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL BE MOVING ACROSS CENTRAL
IOWA THIS EVENING...

STRONG THUNDERSTORMS...CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A
SHORT PERIOD OF TIME WILL BE TRACKING ACROSS CENTRAL IOWA...INCLUDING
THE DES MOINES METRO AREA BETWEEN 6 AND 8 PM THIS WEDNESDAY EVENING.
AS THE STORMS MOVED ACROSS GUTHRIE COUNTY IN WEST CENTRAL IOWA...NEARLY
A FOOT OF WATER WAS OVER HIGHWAY 295 NEAR THE TOWN OF MENLOW...OR ABOUT
40 MILES WEST OF DES MOINES. IN ADDITION...NEARLY 3 INCHES OF RAIN FELL
IN A LITTLE OVER AN HOUR AND A HALF IN THE TOWN OF ANITA IN CASS COUNTY
...OR 60 MILES WEST OF DES MOINES.

THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 25 MILES AN HOUR
WITH ADDITIONAL DEVELOPMENT OCCURRING TO THE WEST OF THIS AREA. RAINFALL
AMOUNTS MAY EXCEED 3 INCHES IN ISOLATED AREAS OF CENTRAL IOWA AS THE
THUNDERSTORMS MOVE ACROSS CENTRAL AND SOUTH CENTRAL IOWA THIS EVENING.

IF YOU SEE WATER OVER A ROADWAY...DO NOT ATTEMPT TO DRIVE THROUGH IT.
IF YOU LIVE NEAR A FLOOD PRONE CREEK OR STREAM...BE PREPARED TO MOVE
TO A PLACE OF SAFETY.

SMITH
Special weather statement, Aug 11, 5:55 PM CDT, 1 hour 36 minutes before
IAZALL-120130-

SPECIAL WEATHER STATEMENT...SPELLING CORRECTION
NATIONAL WEATHER SERVICE DES MOINES IA
555 PM CDT WED AUG 11 1993

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL BE MOVING ACROSS CENTRAL
IOWA THIS EVENING...

STRONG THUNDERSTORMS...CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A
SHORT PERIOD OF TIME WILL BE TRACKING ACROSS CENTRAL IOWA...INCLUDING
THE DES MOINES METRO AREA BETWEEN 6 AND 8 PM THIS WEDNESDAY EVENING.
AS THE STORMS MOVED ACROSS GUTHRIE COUNTY IN WEST CENTRAL IOWA...NEARLY
A FOOT OF WATER WAS OVER HIGHWAY 295 NEAR THE TOWN OF MENLOW...OR ABOUT
40 MILES WEST OF DES MOINES. IN ADDITION...NEARLY 3 INCHES OF RAIN FELL
IN A LITTLE OVER AN HOUR AND A HALF IN THE TOWN OF ANITA IN CASS COUNTY
...OR 60 MILES WEST OF DES MOINES.

THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 25 MILES AN HOUR
WITH ADDITIONAL DEVELOPMENT OCCURRING TO THE WEST OF THIS AREA. RAINFALL
AMOUNTS MAY EXCEED 3 INCHES IN ISOLATED AREAS OF CENTRAL IOWA AS THE
THUNDERSTORMS MOVE ACROSS CENTRAL AND SOUTH CENTRAL IOWA THIS EVENING.

IF YOU SEE WATER OVER A ROADWAY...DO NOT ATTEMPT TO DRIVE THROUGH IT.
IF YOU LIVE NEAR A FLOOD PRONE CREEK OR STREAM...BE PREPARED TO MOVE
TO A PLACE OF SAFETY.

SMITH
Special weather statement, Aug 11, 6:27 PM CDT, 1 hour 4 minutes before
IAC123-C125-150000-

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
627 PM CDT WED AUG 11 1993

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR MAHASKA COUNTY
UNTIL 645 PM...

...THE SEVERE THUNDERSTORM WARNING FOR MARION COUNTY EXPIRED AT 630
PM...

AT 625 PM...A SEVERE THUNDERSTORM WAS NEAR OSKALOOSA IN CENTRAL
MAHASKA COUNTY.  THE THUNDERSTORM WAS MOVING SOUTHEAST AT 25 MPH AND
IT WILL MOVE THROUGH OSKALOOSA AND FREEMONT BY 645 PM.

THE THUNDERSTORMS WERE EAST OF MARION COUNTY AND THE WARNING WILL BE
ALLOWED TO EXPIRE.

THESE THUNDERSTORMS HAVE A HISTORY OF PRODUCING VERY HEAVY
RAIN...STRONG AND DAMAGING WINDS AND HAIL.  IF YOU ARE IN THE PATH OF
THESE STORMS...MOVE TO SAFE INDOOR SHELTER.

JOHNSON
Special weather statement, Aug 11, 6:50 PM CDT, 41 minutes before
IAZALL-120045-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
650 PM CDT WED AUG 11 1993

AT 635 PM CDT...INTENSE THUNDERSTORMS CONTINUED OVER WEST CENTRAL AND
CENTRAL IOWA.  THE STORMS WERE OCCURRING FROM 35 MILES NORTHWEST TO
45 MILES SOUTHWEST OF DES MOINES...IN A 20 MILE WIDE BAND CENTERED FROM
PERRY TO JUST SOUTH OF GREENFIELD.  THESE STORMS WERE PRODUCING
EXTREMELY HEAVY RAIN...FREQUENT LIGHTNING...AND POSSIBLY GUSTY WINDS
AND SMALL HAIL.  IF YOU ARE IN THE PATH OF THESE STORMS SEEK SHELTER
IMMEDIATELY.

THE STORMS WERE PART OF A LARGER AREA OF SHOWERS AND THUNDERSTORMS
LOCATED GENERALLY SOUTH OF A LINE EXTENDING FROM COUNCIL BLUFFS...TO
FORT DODGE...TO BURLINGTON.

MOVEMENT OF THE STORMS AND SHOWERS WAS NORTHEAST AT AROUND 25 MILES AN
HOUR.

KALLMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 7:04 PM CDTFlash Flood WarningDMXDallas116 min
Aug 11, 8:09 PM CDTFlash Flood WarningDMXJasper3 hr
Aug 11, 8:57 PM CDTFlash Flood WarningDMXMarion3 hr
Aug 11, 9:47 PM CDTFlash Flood WarningDMXMahaska, Poweshiek119 min

Nearby

Flash Flood Warnings in Iowa, 1993Every flash flood warning in 1993

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.