Alert archive / Iowa / Flash Flood Warnings in 1992

Flash Flood Warning 6, NWS Des Moines, IA

July 30, 1992Mahaska County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 30, 1992, 3:24 AM CDT for Mahaska County, Iowa. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
Jul 30, 1992, 3:24 AM CDT (08:24 UTC)
Expired
Jul 30, 1992, 5:30 AM CDT
In force
2 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Mahaska County, IA

The nearest sounding before it

Omaha, NE (KOVN), launched 00:00Z, 8.4 hours before the alert went out and 311 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 1992-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2191 joules per kilogram.LCLEL10008507005003002001001 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 1992-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 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
2191 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
729 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
204 m²/s²
Significant tornado parameter
1.8
Supercell composite
9.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 300826
FFWDSM
IAC123-301030-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
324 AM CDT THU JUL 30 1992
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  530 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTH CENTRAL IOWA
 
   ...MAHASKA COUNTY
 
AT 312 AM...THE MAHASKA COUNTY SHERIFF REPORTED WATER OVER HIGHWAY 163
IN SEVERAL PLACES WEST OF OSKALOOSA OR ABOUT 50 MILES TO THE SOUTHEAST
OF DES MOINES. IN ADDITION...SEVERAL CREEKS WERE OUT OF THEIR BANKS NEAR
HIGHWAY 92 WEST OF OSKALOOSA.
 
PERIODS OF SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL WILL CONTINUE
MOVING ACROSS THE MAKASKA COUNTY AREA UNTIL 5AM.
 
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.
 
DO NOT DRIVE YOUR VEHICLE WHERE WATER COVERS THE ROADWAY OF UNKNOWN
DEPTH.  ONLY TWO FEET OF WATER WILL LIFT MOST VEHICLES AND SWEEP THEM
AWAY.
 
CEW

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 29, 11:14 PM CDT, 4 hours 10 minutes before
IAZALL-300510-

SPECIAL WEATHER STATEMENT AND WEATHER UPDATE FOR IOWA
NATIONAL WEATHER SERVICE DES MOINES IA
1115 PM CDT WED JUL 29 1992

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR A SMALL PART OF SOUTH CENTRAL
AND SOUTHWEST IOWA UNTIL 1 AM CDT THURSDAY MORNING...

AT 1108 PM CDT...AN INTENSE THUNDERSTORM WAS OCCURRING OVER SOUTHWEST
IOWA...35 TO 40 MILES SOUTHEAST OF COUNCIL BLUFFS OR 10 MILES NORTHEAST
OF RED OAK.  THIS THUNDERSTORM WAS CAPABLE OF PRODUCING HAIL...STRONG
WIND...DANGEROUS LIGHTNING...AND HEAVY DOWNPOURS.

PERSONS NEAR THIS STORM SHOULD SEEK SHELTER AND MONITOR WEATHER REPORTS
FOR FURTHER DEVELOPMENTS.

ALSO...ISOLATED STRONG THUNDERSTORMS WERE OCCURRING OVER SOUTH CENTRAL
AND SOUTHEAST IOWA.  ONE AREA OF STORMS WAS 50 TO 60 MILES SOUTH OF DES
MOINES...NEAR LAMONI.  ANOTHER AREA OF STORMS WAS 25 TO 45 MILES NORTH-
WEST OF BURLINGTON NEAR BRIGHTON AND MOUNT PLEASANT.
/
THE STORMS WERE MOVING SOUTHEAST AT 35 MILES AN HOUR.

THE ONE TO TWO HOUR OUTLOOK IS FOR ISOLATED STRONG STORMS AND SCATTERED
SHOWERS TO CONTINUE OVER THE SOUTHERN THIRD OF IOWA.

MILLER
Special weather statement, Jul 29, 11:51 PM CDT, 3 hours 33 minutes before
IAZALL-300510-

SPECIAL WEATHER STATEMENT AND WEATHER UPDATE FOR IOWA
NATIONAL WEATHER SERVICE DES MOINES IA
1150 PM CDT WED JUL 29 1992

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR PARTS OF SOUTHWEST AND SOUTH
CENTRAL IOWA UNTIL 6 AM CDT THURSDAY MORNING...

AT 1127 PM CDT...WIDELY SCATTERED STRONG AND INTENSE THUNDERSTORMS WERE
OCCURRING OVER THE SOUTH TWO TIERS OF IOWAS COUNTIES.  THE STRONGEST
STORMS WERE LOCATED 60 MILES SOUTH OF DES MOINES NEAR LAMONI...AND 45
MILES SOUTHEAST OF COUNCIL BLUFFS OR 10 MILES EAST OF RED OAK.  THESE
STORMS WERE CAPABLE OF PRODUCING SMALL HAIL...STRONG WIND...DEADLY
LIGHTNING...AND HEAVY DOWNPOURS.

ALSO...THUNDERSHOWERS AND SHOWERS WERE SCATTERED OVER THE SOUTHERN
QUARTER OF IOWA...SOUTH OF A COUNCIL BLUFFS TO DES MOINES TO CLINTON
LINE.  CLINTON IS 25 MILES NORTHEAST OF DAVENPORT.

THE STORMS AND SHOWERS WERE MOVING SOUTHEAST AT 30 MILES AN HOUR.
/
MILLER
Special weather statement, Jul 29, 11:56 PM CDT, 3 hours 28 minutes before
IAZALL-300510-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY...CORRECTED FOR HEADING...
NATIONAL WEATHER SERVICE DES MOINES IA
1150 PM CDT WED JUL 29 1992

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR PARTS OF SOUTHWEST AND SOUTH
CENTRAL IOWA UNTIL 6 AM CDT THURSDAY MORNING...

AT 1127 PM CDT...WIDELY SCATTERED STRONG AND INTENSE THUNDERSTORMS WERE
OCCURRING OVER THE SOUTH TWO TIERS OF IOWAS COUNTIES.  THE STRONGEST
STORMS WERE LOCATED 60 MILES SOUTH OF DES MOINES NEAR LAMONI...AND 45
MILES SOUTHEAST OF COUNCIL BLUFFS OR 10 MILES EAST OF RED OAK.  THESE
STORMS WERE CAPABLE OF PRODUCING SMALL HAIL...STRONG WIND...DEADLY
LIGHTNING...AND HEAVY DOWNPOURS.

ALSO...THUNDERSHOWERS AND SHOWERS WER
E SCATTERED OVER THE SOUTHERN
QUARTER OF IOWA...SOUTH OF A COUNCIL BLUFFS TO DES MOINES TO CLINTON
LINE.  CLINTON IS 25 MILES NORTHEAST OF DAVENPORT.

THE STORMS AND SHOWERS WERE MOVING SOUTHEAST AT 30 MILES AN HOUR.
/
MILLER
Special weather statement, Jul 30, 12:44 AM CDT, 2 hours 40 minutes before
IAZALL-300510-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1245 AM CDT THU JUL 30 1992

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR PARTS OF SOUTHWEST AND SOUTH
   CENTRAL IOWA UNTIL 6 AM CDT THIS MORNING...
...A FLASH FLOOD WATCH FOR PARTS OF SOUTHWEST AND SOUTH CENTRAL IOWA
   UNTIL 6 AM CDT THIS MORNING...

AT 1233 AM CDT...SHOWERS AND ISOLATED STRONG THUNDERSTORMS CONTINUED
OVER ABOUT THE SOUTHERN THIRD OF IOWA. THE SHOWERS AND STORMS WERE
SOUTH OF A LINE FROM OMAHA/COUNCIL BLUFFS NORTHEAST TO DES MOINES THEN
SOUTHEAST TO 20 MILES NORTH OF BURLINGTON.

THE STRONGEST STORM IN THIS AREA WAS LOCATED 50 MILES SOUTHWEST OF
DES MOINES BETWEEN CUMBERLAND AND CRESTON. THIS STORMS WILL PRODUCE
VERY HEAVY RAIN...FREQUENT DEADLY LIGHTNING AND POSSIBLY SOME SMALL
HAIL.

THE SHOWERS AND STORMS WERE MOVING EAST AT 25 TO 30 MILES AN HOUR.

BARLOW
Special weather statement, Jul 30, 1:47 AM CDT, 1 hour 37 minutes before
IAZALL-300740-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
145 AM CDT THU JUL 30 1992

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR PARTS OF SOUTHWEST AND SOUTH
   CENTRAL IOWA UNTIL 6 AM CDT THIS MORNING...
...A FLASH FLOOD WATCH FOR PARTS OF SOUTHWEST AND SOUTH CENTRAL IOWA
   UNTIL 6 AM CDT THIS MORNING...

AT 133 AM CDT...SHOWERS AND ISOLATED STRONG THUNDERSTORMS CONTINUED
OVER ABOUT THE SOUTHERN HALF OF IOWA. THE SHOWERS AND STORMS WERE
SOUTH OF A LINE FROM 30 MILES SOUTH OF SIOUX CITY...NEAR ONAWA...EAST
THROUGH DES MOINES TO JUST SOUTH OF CEDAR RAPIDS.

ALTHOUGH THE OVERALL INTENSITY OF THE THUNDERSTORMS HAS SHOWN A SLIGHT
DECREASE SINCE 1230...SEVERAL OF THE STORMS PARTICULARLY THOSE ALONG
A LINE FROM OMAHA/COUNCIL BLUFFS THROUGH DES MOINES WILL PRODUCE VERY
HEAVY RAINS. THERE WILL BE SOME LOCALIZED STREET FLOODING IN AROUND THE
DES MOINES METROPLOITAN AREA FOR THE NEXT SEVERAL HOURS.

THE SHOWERS AND STORMS WERE MOVING EAST AT 25 TO 30 MILES AN HOUR.

BARLOW
Special weather statement, Jul 30, 2:54 AM CDT, 30 minutes before
IAZALL-300840-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
247 AM CDT THU JUL 30 1992

...A FLASH FLOOD WATCH FOR PARTS OF SOUTHWEST...CENTRAL AND EAST CENTRAL
   IOWA UNTIL 6 AM CDT THIS MORNING...

AT 234 AM CDT...AN EXPANDING AREA OF NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS...SOME PRODUCING VERY HEAVY RAIN...CONTINUED OVER MOST
OF THE SOUTHERN HALF OF IOWA. THE SHOWERS AND STORMS WERE LOCATED
SOUTH OF A LINE FROM 25 MILES SOUTH OF SIOUX CITY SOUTHEAST TO JUST
SOUTH OF CEDAR RAPIDS.

THE HEAVIEST RAINS HAVE BEEN OCCURRING ALONG AND 20 MILES EITHER SIDE
OF A LINE FROM 25 MILES NORTHEAST OF OMAHA/COUNCIL BLUFFS...NEAR AVOCA
EAST THROUGH DES MOINES TO 15 MILES SOUTH OF CEDAR RAPIDS...NEAR KALONA.

STREET FLOODING HAS BEEN REPORTED IN OSKALOOSA AND AROUND THE DES MOINES
METROPOLITAN AREA. WATER WAS REPORTED OVER HIGHWAY 5...2 MILES EAST OF
CARLISLE. ADDITIONAL FLOODING IS EXPECTED THROUGHOUT THIS AREA...AS
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH
THIS AREA FOR ATLEAST THE NEXT 3 TO 4 HOURS.

MOTORISTS ARE URGED TO WATCH FOR RISING WATER PARTICULARLY IN LOW LYING
AREAS THROUGHOUT CENTRAL AND EAST CENTRAL IOWTA THIS MORNING. DO NOT
ATTEMPT TO CROSS FLOODED ROADS...AS AN AUTOMOBILE COULD BE QUICKLY
SWEPT AWAY.

THE SHOWERS AND STORMS WERE MOVING EAST NORTHEAST AT 20 TO 25 MILES
AN HOUR.

BARLOW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 2:49 AM CDTFlash Flood WarningDMXWarren116 min

Nearby

Flash Flood Warnings in Iowa, 1992Every flash flood warning in 1992

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.