Alert archive / Iowa / Flash Flood Warnings in 1993

Flash Flood Warning 80, NWS Des Moines, IA

July 22, 1993Cass County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 22, 1993, 8:27 PM CDT for Cass County, Iowa. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 22, 1993, 8:27 PM CDT (01:27 UTC)
Expired
Jul 22, 1993, 11:30 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Cass County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.5 hours before the alert went out and 120 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 1993-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2002 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 1993-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 square meters per square second.19395878Sfc1 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
2002 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
664 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
160 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 230128
FFWDSM
IAC029-230430-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
827 PM CDT THU JUL 22 1993
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL 1130 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION(S)...
 
IN SOUTHWEST IOWA
 
   ...CASS COUNTY
 
AT 820 PM CDT THUNDERSTORMS WITH HEAVY RAINS WERE OCCURRING IN CASS
COUNTY. REPORTS OF NEARLY THREE INCHES...STREET FLOODING IN GRISWOLD.
 
CREEKS AFFECTED BY THE HEAVY RAINS WERE SEVEN MILE...WALNUT AND THE
NODAWAY RIVER BETWEEN MASSENA SOUTHWEST TOWARD GRANT IN NORTHEASTERN
MONTGOMERY COUNTY.
 
THUNDERSTORMS WILL CONTINUE TO MOVE OVER THE COUNTY AND CAUSE MORE
FLOODING DURING THE EVENING HOURS.
 
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE
THE DANGERS OF FLOODS AND FLASH FLOODS.  IF FLASH FLOODING IS
OBSERVED...ACT QUICKLY.  MOVE UP TO ESCAPE FLOOD WATERS.  DO
NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.
 
MOST DEATHS IN FLASH FLOODING OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS
THE ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A
SMALL ONE...ON FOOT.
 
 
FORSTER/JM

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, Jul 22, 6:44 PM CDT, 1 hour 43 minutes before
IAZ060-230040-

RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
645 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 630 PM CDT...SCATTERED VERY STRONG AND INTENSE THUNDERSTORMS HAD
DEVELOPED OVER SOUTHWEST IOWA.  THESE STORMS WERE LOCATED 25 TO 30
MILES EAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF OAKLAND...AND
25 MILES SOUTHEAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF MALVERN.

THESE THUNDERSTORMS CONTAIN VERY HEAVY RAINS AND ARE CAPABLE OF
PRODUCING SMALL HAIL...STRONG WIND...AND DEADLY LIGHTNING.

ALSO...WIDELY SCATTERED SHOWERS WERE OCCURRING OVER CENTRAL IOWA NEAR
WINTERSET...ADAIR...AND PERRY...OR 20 TO 40 MILES SOUTLHWEST THROUGH
NORTHWEST OF DES MOINES.
.

MILLER
Special weather statement, Jul 22, 6:45 PM CDT, 1 hour 42 minutes before
IAZ060-230040-

RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
645 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 630 PM CDT...SCATTERED VERY STRONG AND INTENSE THUNDERSTORMS HAD
DEVELOPED OVER SOUTHWEST IOWA.  THESE STORMS WERE LOCATED 25 TO 30
MILES EAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF OAKLAND...AND
25 MILES SOUTHEAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF MALVERN.

THESE THUNDERSTORMS CONTAIN VERY HEAVY RAINS AND ARE CAPABLE OF
PRODUCING SMALL HAIL...STRONG WIND...AND DEADLY LIGHTNING.

ALSO...WIDELY SCATTERED SHOWERS WERE OCCURRING OVER CENTRAL IOWA NEAR
WINTERSET...ADAIR...AND PERRY...OR 20 TO 40 MILES SOUTHWEST THROUGH
NORTHWEST OF DES MOINES.
.

MILLER
Special weather statement, Jul 22, 6:47 PM CDT, 1 hour 40 minutes before
IAZ060-230040-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY...CORRECT FOR HEADING
NATIONAL WEATHER SERVICE DES MOINES IA
647 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 630 PM CDT...SCATTERED VERY STRONG AND INTENSE THUNDERSTORMS HAD
DEVELOPED OVER SOUTHWEST IOWA.  THESE STORMS WERE LOCATED 25 TO 30
MILES EAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF OAKLAND...AND
25 MILES SOUTHEAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF MALVERN.

THESE THUNDERSTORMS CONTAIN VERY HEAVY RAINS AND ARE CAPABLE OF
PRODUCING SMALL HAIL...STRONG WIND...AND DEADLY LIGHTNING.

ALSO...WIDELY SCATTERED SHOWERS WERE OCCURRING OVER CENTRAL IOWA NEAR
WINTERSET...ADAIR...AND PERRY...OR 20 TO 40 MILES SOUTHWEST THROUGH
NORTHWEST OF DES MOINES.
.
THE THUNDERSTORMS AND SHOWERS WERE MOVING EAST/NORTHEAST AT 15
MILES AN HOUR.

MILLER
Special weather statement, Jul 22, 6:48 PM CDT, 1 hour 39 minutes before
IAZ060-230040-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY...CORRECT FOR HEADING
NATIONAL WEATHER SERVICE DES MOINES IA
647 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 630 PM CDT...SCATTERED VERY STRONG AND INTENSE THUNDERSTORMS HAD
DEVELOPED OVER SOUTHWEST IOWA.  THESE STORMS WERE LOCATED 25 TO 30
MILES EAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF OAKLAND...AND
25 MILES SOUTHEAST OF COUNCIL BLUFFS NEAR THE COMMUNITY OF MALVERN.

THESE THUNDERSTORMS CONTAIN VERY HEAVY RAINS AND ARE CAPABLE OF
PRODUCING SMALL HAIL...STRONG WIND...AND DEADLY LIGHTNING.

ALSO...WIDELY SCATTERED SHOWERS WERE OCCURRING OVER CENTRAL IOWA NEARZ
WINTERSET...ADAIR...AND PERRY...OR 20 TO 40 MILES SOUTHWEST THROUGH
NORTHWEST OF DES MOINES.
.
THE THUNDERSTORMS AND SHOWERS WERE MOVING EAST/NORTHEAST AT 15
MILES AN HOUR.

MILLER
Special weather statement, Jul 22, 7:45 PM CDT, 42 minutes before
IAZ060-230145-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
745 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 731 PM CDT...A LINE OF VERY STRONG AND INTENSE THUNDERSTORMS
CONTINUED OVER SOUTHWEST IOWA.  THIS 10 TO 15 MILE WIDE BAND OF
STORMS WAS LOCATED FROM 50 MILES NORTHEAST OF COUNCIL BLUFFS...NEAR
EXIRA...TO 35 MILES SOUTH OF COUNCIL BLUFFS...NEAR NEBRASKA CITY
NEBRASKA.

THESE STORMS WERE PRODUCING VERY HEAVY RAINFALL...DEADLY LIGHTNING...
AND COULD PRODUCE HAIL AND DAMAGING WIND.  PERSONS IN THE PATH OF THESE
STORMS SHOULD MONITOR LOCAL NEWS OUTLETS AND BE ALERT TO THREATENING
WEATHER.

THE THUNDERSTORMS WERE MOVING EAST/NORTHEAST AT 15 TO 20 MILES AN HOUR.
.
MILLER
Special weather statement, Jul 22, 7:46 PM CDT, 41 minutes before
IAZ060-230145-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
745 PM CDT THU JUL 22 1993

...A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHWEST THIRD OF IOWA
   TONIGHT...

AT 731 PM CDT...A LINE OF VERY STRONG AND INTENSE THUNDERSTORMS
CONTINUED OVER SOUTHWEST IOWA.  THIS 10 TO 15 MILE WIDE BAND OF
STORMS WAS LOCATED FROM 50 MILES NORTHEAST OF COUNCIL BLUFFS...NEAR
EXIRA...TO 35 MILES SOUTH OF COUNCIL BLUFFS...NEAR NEBRASKA CITY
NEBRASKA.

THESE STORMS WERE PRODUCING VERY HEAVY RAINFALL...DEADLY LIGHTNING...
AND COULD PRODUCE HAIL AND DAMAGING WIND.  PERSONS IN THE PATH OF THESE
STORMS SHOULD MONITOR LOCAL NEWS OUTLETS AND BE ALERT TO THREATENING
WEATHER.

THE THUNDERSTORMS WERE MOVING EAST/NORTHEAST AT 15 TO 20 MILES AN HOUR.
.
MILLER

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 2:08 AM CDTFlash Flood WarningDMXTaylor4 hr

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.