Alert archive / Iowa / Flash Flood Warnings in 1993

Flash Flood Warning 83, NWS Des Moines, IA

July 23, 1993Decatur County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 23, 1993, 11:43 PM CDT for Decatur County, Iowa. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 23, 1993, 11:43 PM CDT (04:43 UTC)
Expired
Jul 24, 1993, 2:45 AM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Decatur County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.7 hours before the alert went out and 226 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 1993-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 465 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 1993-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 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
465 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
966 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 240444
FFWDSM
IAC053-240745-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1143 PM CDT FRI JUL 23 1993
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  300 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION(S)...
 
IN SOUTH CENTRAL IOWA
 
   ...DECATUR COUNTY
 
AT 1140 PM CDT RADAR INDICATED TORRENTIAL RAIN PRODUCING THUNDERSTORMS
OVER EASTERN DECATUR COUNTY NEAR GRAND RIVER...55 MILES SOUTHWEST OF DES
MOINES. RAINFALL AMOUNTS IN EXCESS OF SEVERAL INCHES IN A SHORT PERIOD
OF TIME ARE EXPECTED WITH THESE THUNDERSTORMS.
 
SOME SMALL STREAMS IN THE WARNING AREA INCLUDE...JONATHAN...ELK...SHORT.
SOME TOWNS INCLUDED IN THE WARNING ARE...LEON...DAVIS CITY...GARDEN
GROVE...AND LAMONI.
 
 
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY.  MOVE TO HIGHER GROUND.
 
BELLES

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 23, 9:30 PM CDT, 2 hours 13 minutes before
IAZALL-240400-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
930 PM CDT FRI JUL 23 1993

              ...SHORT TERM RAINFALL OUTLOOK FOR IOWA...

AT 915 PM RADAR INDICATED NUMEROUS THUNDERSTORMS IN SOUTHEAST AND EAST
CENTRAL IOWA. STRONG THUNDERSTORMS WERE ALSO LOCATED OVER PARTS OF
SOUTHEAST NEBRASKA AND NORTHEAST KANSAS AND WERE BEGINNING TO SPREAD
INTO SOUTHWEST IOWA. IN THE NEXT HOUR EXPECT THE THUNDERSTORMS TO
CONTINUE IN EAST CENTRAL AND SOUTHEAST IOWA AND BECOME MORE NUMEROUS
OVER THE SOUTHWEST PART OF THE STATE. SOME OF THESE THUNDERSTORMS MAY
CONTAIN VERY HEAVY RAIN.

THUNDERSTORMS WILL SPREAD THROUGHOUT THE ENTIRE SOUTHERN HALF OF IOWA
IN THE NEXT FEW HOURS. THESE THUNDERSTORMS HAVE THE POTENTIAL TO PRODUCE
LARGE AMOUNTS OF RAIN IN A SHORT TIME PERIOD...THUS A FLASH FLOOD WATCH
IS IN EFFECT OVER THIS PART OF THE STATE.  OVER THE NORTH HALF OF IOWA
LOOK FOR DRY CONDITIONS WITH SCATTERED SHOWERS AFTER MIDNIGHT.
.
IOWANS SHOULD CONTINUE TO MONITOR THE LATEST FORECASTS AND WEATHER
STATEMENTS.  IF HEAVY RAIN PRODUCING THUNDERSTORMS OCCUR IN YOUR
AREA...BE PREPARED TO MOVE TOWARD SAFE GROUND.  REMEMBER NEVER TO CROSS
A FLOODED ROADWAY IN YOUR AUTOMOBILE...IT MAY HIDE A WASHOUT.

BAILEY
Special weather statement, Jul 23, 9:32 PM CDT, 2 hours 11 minutes before
IAZALL-240400-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
930 PM CDT FRI JUL 23 1993

              ...SHORT TERM RAINFALL OUTLOOK FOR IOWA...

AT 915 PM RADAR INDICATED NUMEROUS THUNDERSTORMS IN SOUTHEAST AND EAST
CENTRAL IOWA. STRONG THUNDERSTORMS WERE ALSO LOCATED OVER PARTS OF
SOUTHEAST NEBRASKA AND NORTHEAST KANSAS AND WERE BEGINNING TO SPREAD
INTO SOUTHWEST IOWA. IN THE NEXT HOUR EXPECT THE THUNDERSTORMS TO
CONTINUE IN EAST CENTRAL AND SOUTHEAST IOWA AND BECOME MORE NUMEROUS
OVER THE SOUTHWEST PART OF THE STATE. SOME OF THESE THUNDERSTORMS MAY
CONTAIN VERY HEAVY RAIN.

THUNDERSTORMS WILL SPREAD THROUGHOUT THE ENTIRE SOUTHERN HALF OF IOWA
IN THE NEXT FEW HOURS. THESE THUNDERSTORMS HAVE THE POTENTIAL TO PRODUCE
LARGE AMOUNTS OF RAIN IN A SHORT TIME PERIOD...THUS A FLASH FLOOD WATCH
IS IN EFFECT OVER THIS PART OF THE STATE.  OVER THE NORTH HALF OF IOWA
LOOK FOR DRY CONDITIONS WITH SCATTERED SHOWERS AFTER MIDNIGHT.
.
IOWANS SHOULD CONTINUE TO MONITOR THE LATEST FORECASTS AND WEATHER
STATEMENTS.  IF HEAVY RAIN PRODUCING THUNDERSTORMS OCCUR IN YOUR
AREA...BE PREPARED TO MOVE TOWARD SAFE GROUND.  REMEMBER NEVER TO CROSS
A FLOODED ROADWAY IN YOUR AUTOMOBILE...IT MAY HIDE A WASHOUT.

BAILEY
Special weather statement, Jul 23, 9:43 PM CDT, 2 hours before
IAZ060-240345-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
9 44 PM CDT FRI JUL 23 1993

...A FLASH FLOOD WATCH FOR THE SOUTHWEST QUARTER OF IOWA FOR LATE
   TONIGHT INTO SATURDAY MORNING...

AT 9 30 PM CDT...SCATTERED STRONG THUNDERSTORMS CONTINUED OVER
SOUTHEAST IOWA...MOSTLY EAST OF A MARSHALLTOWN TO OTTUMWA LINE.
ALSO...ISOLATED VERY STRONG THUNDERSTORMS DEVELOPED OVER SOUTHWEST
AND SOUTH CENTRAL IOWA SOUTH OF A MALVERN/CRESTON/MELCHER LINE.
MALVERN IS 20 MILES SOUTH OF COUNCIL BLUFFS...CRESTON IS 50 MILES
SOUTHWEST OF DES MOINES...AND MELCHER IS 30 MILES SOUTHEAST OF DES
MOINES.

ALL OF THESE THUNDERSTORMS COULD PRODUCE HEAVY RAIN IN A SHORT PERIOD
OF TIME.  PERSONS IN THE PATH OF THESE STORMS SHOULD BE PREPARED TO
SEEK HIGHER GROUND IF ROADWAYS AND LOW LYING AREAS EXPERIENCE FLOODING.
.
THE THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.

MILLER
Special weather statement, Jul 23, 9:43 PM CDT, 2 hours before
IAZ060-240345-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
9 44 PM CDT FRI JUL 23 1993

...A FLASH FLOOD WATCH FOR THE SOUTHWEST QUARTER OF IOWA FOR LATE
   TONIGHT INTO SATURDAY MORNING...

AT 9 30 PM CDT...SCATTERED STRONG THUNDERSTORMS CONTINUED OVER
SOUTHEAST IOWA...MOSTLY EAST OF A MARSHALLTOWN TO OTTUMWA LINE.
ALSO...ISOLATED VERY STRONG THUNDERSTORMS DEVELOPED OVER SOUTHWEST
AND SOUTH CENTRAL IOWA SOUTH OF A MALVERN/CRESTON/MELCHER LINE.
MALVERN IS 20 MILES SOUTH OF COUNCIL BLUFFS...CRESTON IS 50 MILES
SOUTHWEST OF DES MOINES...AND MELCHER IS 30 MILES SOUTHEAST OF DES
MOINES.

ALL OF THESE THUNDERSTORMS COULD PRODUCE HEAVY RAIN IN A SHORT PERIOD
OF TIME.  PERSONS IN THE PATH OF THESE STORMS SHOULD BE PREPARED TO
SEEK HIGHER GROUND IF ROADWAYS AND LOW LYING AREAS EXPERIENCE FLOODING.
.
THE THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.

MILLER
Special weather statement, Jul 23, 10:45 PM CDT, 58 minutes before
IAZ060-240445-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
10 45 PM CDT FRI JUL 23 1993

...A FLASH FLOOD WATCH FOR THE SOUTH HALF OF IOWA FOR LATE
   TONIGHT INTO SATURDAY MORNING...

AT 10 30 PM CDT...SCATTERED VERY STRONG THUNDERSTORMS CONTINUED OVER
SOUTHWEST AND SOUTHEAST IOWA.  THE STRONGEST STORMS WERE LOCATED 50
MILES SOUTHEAST OF COUNCIL BLUFFS ALONG THE MISSOURI BORDER SOUTH OF
CLRAINDA AND 50 TO 60 MILES SOUTHWEST OF DES MOINES NEAR DIAGONAL AND
MOUNT AYR.  OTHER STRONG STORMS WERE LOCATED 40 TO 70 MILES WEST OF
DAVENPORT .

ALL OF THESE STORMS WERE CAPABLE OF PRODUCING LARGE AMOUNTS OF RAIN
IN A SHORT PERIOD OF TIME.  PERSONS IN THE PATH OF THESE STORMS SHOULD
MONITOR THE WEATHER SITUATION CLOSELY THROUGH LOCAL MEDIA OUTLETS AND
SEEK HIGHER GROUND IF ROADWAYS AND LOW LYING AREAS BECOME INUNDATED.
.
THE THUNDERSTORMS WERE MOVING EAST AT 20 MILES AN HOUR.

MILLER
Special weather statement, Jul 23, 10:45 PM CDT, 58 minutes before
IAZ060-240445-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
10 45 PM CDT FRI JUL 23 1993

...A FLASH FLOOD WATCH FOR THE SOUTH HALF OF IOWA FOR LATE
   TONIGHT INTO SATURDAY MORNING...

AT 10 30 PM CDT...SCATTERED VERY STRONG THUNDERSTORMS CONTINUED OVER
SOUTHWEST AND SOUTHEAST IOWA.  THE STRONGEST STORMS WERE LOCATED 50
MILES SOUTHEAST OF COUNCIL BLUFFS ALONG THE MISSOURI BORDER SOUTH OF
CLRAINDA AND 50 TO 60 MILES SOUTHWEST OF DES MOINES NEAR DIAGONAL AND
MOUNT AYR.  OTHER STRONG STORMS WERE LOCATED 40 TO 70 MILES WEST OF
DAVENPORT .

ALL OF THESE STORMS WERE CAPABLE OF PRODUCING LARGE AMOUNTS OF RAIN
IN A SHORT PERIOD OF TIME.  PERSONS IN THE PATH OF THESE STORMS SHOULD
MONITOR THE WEATHER SITUATION CLOSELY THROUGH LOCAL MEDIA OUTLETS AND
SEEK HIGHER GROUND IF ROADWAYS AND LOW LYING AREAS BECOME INUNDATED.
.
THE THUNDERSTORMS WERE MOVING EAST AT 20 MILES AN HOUR.

MILLER

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 11:16 PM CDTFlash Flood WarningDMXRinggold3 hr
Jul 24, 12:33 AM CDTFlash Flood WarningDMXWayne3 hr
Jul 24, 1:56 AM CDTFlash Flood WarningDMXKeokuk, Washington3 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.