Alert archive / Iowa / Flash Flood Warnings in 1990

Flash Flood Warning 27, NWS Des Moines, IA

July 27, 1990Hamilton County, Hardin County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 27, 1990, 11:45 AM CDT for Hamilton County, Hardin County, Iowa. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Jul 27, 1990, 11:45 AM CDT (16:45 UTC)
Expired
Jul 27, 1990, 4:00 PM CDT
In force
4 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Hamilton County, IA, Hardin County, IA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 4.8 hours before the alert went out and 267 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 12:00Z on 1990-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 1990-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3635 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 271646
FFWDSM
IAC079-083-272100-

FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CDT FRI JUL 27 1990

...FLOOD WARNING FOR HAMILTON AND HARDIN COUNTIES UNTIL 4 PM...

SINCE 930 AM...A LINE OF THUNDERSTORMS HAS BEEN ANCHORED OVER
HAMILTON AND HARDIN COUNTIES.  THE LINE EXTENDED FROM A FEW MILES
SOUTHEAST OF FORT DODGE...JUST SOUTH OF WEBSTER CITY...TO NEAR
ELDORA.   THIS AREA IS SOME 50 TO 70 MILES NORTH OF DES MOINES.

THESE STORMS HAVE BEEN WEAKENING SLOWLY SINCE ABOUT 10 AM...BUT THEIR
NEARLY STATIONARY MOVEMENT HAS BEEN CAUSING LOCALLIZED HEAVY RAINS.
THESE RAINS WILL CAUSE WIDESPREAD FLOODING OF CREEKS AND STREAMS IN THE
WARNING AREA.

PEOPLE LIVING IN FLOOD PRONE AREAS SHOULD MOVE TO HIGHER GROUND.
NEVER TRY TO CROSS FLOOD WATERS OVER KNEE DEEP...OR DRIVE THROUGH
FLOOD WATERS OF UNKNOWN DEPTH.

AT 1130 AM...THE HAMILTON COUNTY SHERIFFS DEPARTMENT REPORTED THAT...
AS A PRECAUTIONARY MEASURE...EVACUATIONS WERE BEGINNING AT A BIBLE
CAMP NEAR RANDALL...IN THE EXTREME SOUTHERN PART OF THE COUNTY.

TRUETT

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 27, 6:43 AM CDT, 5 hours 2 minutes before
IAZALL-271300-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
645 AM CDT FRI JUL 27 1990

...FLASH FLOOD WATCH FOR SOUTHWEST AND CENTRAL IOWA THIS AFTERNOON
   AND TONIGHT....

AT 630 AM...SCATTERED THUNDERSTORMS...SOME WITH VERY HEAVY RAIN...
CONTINUED OVER MUCH OF THE EAST ONE HALF OF THE STATE.  THE STRONGEST
THUNDERSTORMS WERE LOCATED 10 TO 30 MILES SOUTHWEST OF MASON CITY AND
65 MILES NORTHEAST OF DES MOINES...NEAR ACKLEY.

THE AREA OF STORMS AND SHOWERS WAS EAST OF ALINE FROM THE ALGONA AREA
...50 MILES WEST OF MASON CITY...TO THE AFTON AREA...40 MILES
SOUTHWEST OF DES MOINES.

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

DM
Special weather statement, Jul 27, 7:43 AM CDT, 4 hours 2 minutes before
IAZALL-271400-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
745 AM CDT FRI JUL 27 1990

...FLASH FLOOD WATCH FOR SOUTHWEST AND CENTRAL IOWA THIS AFTERNOON
   AND TONIGHT....

AT 730 AM...SCATTERED THUNDERSTORMS AND SHOWERS...SOME WITH VERY HEAVY
RAIN...CONTINUED OVER THE EAST HALF OF THE STATE.  ALSO...ISOLATED
THUNDERSTORMS AND SHOWERS HAD DEVELOPED OVER THE WEST CENTRAL AND
NORTHWEST COUNTIES.  THE STRONGEST STORMS WERE LOCATED 10 TO 20 MILES
WEST AND SOUTHWEST OF MASON CITY...AND NEAR ROCKWELL CITY...HUMBOLDT...
AND DENISON...OR FROM 60 MILES SOUTHWEST OF MASON CITY TO 50 MILES
SOUTHEAST OF SIOUX CITY.

THE THUNDERSTORMS AND SHOWERS WERE MOVING NOR<THEAST AT 20 MILES AN HOUR.

DM
Special weather statement, Jul 27, 8:33 AM CDT, 3 hours 12 minutes before
IAZALL-271430-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
833 AM CDT FRI JUL 27 1990

...FLASH FLOOD WATCH FOR SOUTHWEST AND CENTRAL IOWA THIS AFTERNOON
   AND TONIGHT....

AT 825 AM...NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS CONTINUED OVER
ABOUT THE NORTH TWO THIRDS OF IOWA.

THE SHOWERS AND STORMS WERE MOSTLY NORTH OF A LINE EXTENDING FROM
30 MILES NORTH OF BURLINGTON...TO NEAR OTTUMWA...TO DES MOINES...
TO ABOUT 40 MILES SOUTH OF SIOUX CITY.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 15 MILES AN HOUR.

WPM
Special weather statement, Jul 27, 9:42 AM CDT, 2 hours 3 minutes before
IAZALL-271542-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
942 AM CDT FRI JUL 27 1990

...FLASH FLOOD WATCH REMAINS IN EFFECT FOR SOUTHWEST AND CENTRAL IOWA
THIS AFTERNOON AND TONIGHT...AND NORTHWEST IOWA TODAY AND TONIGHT...

AT 930 AM CDT...NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS CONTINUED
OVER NORTHEAST AND NORTH CENTRAL IOWA...WHILE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS CONTINUED OVER THE NORTHWEST.

THE SHOWERS AND STORMS WERE MOSTLY NORTH OF A LINE EXTENDING FROM
NEAR DAVENPORT/MOLINE...TO 25 MILES NORTH OF DES MOINES...TO 40 MILES
SOUTHEAST OF SIOUX CITY.

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

WPM
Special weather statement, Jul 27, 10:38 AM CDT, 1 hour 7 minutes before
IAZALL-271640-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1035 AM CDT FRI JUL 27 1990

...FLOOD/FLASH FLOOD WATCH SOUTHWEST...CENTRAL...AND NORTHEAST IOWA
   THIS AFTERNOON AND TONIGHT...

AT 1025 AM CDT...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS CONTINUED
OVER NORTH CENTRAL AND NORTHEAST IOWA.

THE HEAVIEST RAINFALL WAS LOCATED IN ABOUT A 10 MILE WIDE BAND...
FROM NEAR ROCKWELL CITY...TO JEWELL...TO ELDORA...OR FROM
80 MILE SOUTHWEST...TO 80 MILES SOUTH OF MASON CITY.

THE SHOWERS AND STORMS WERE MOSTLY NORTH OF A LINE EXTENDING FROM
NEAR DAVENPORT/MOLINE...TO CEDAR RAPIDS...TO 80 MILES NORTHWEST OF
DES MOINES.

THE SHOWERS AND STORMS WERE MOV=ING NORTHEAST AT 15 MILES AN HOUR.

WPM
Special weather statement, Jul 27, 11:30 AM CDT, 15 minutes before
IAZALL-271730-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1130 AM CDT FRI JUL 27 1990

...FLOOD/FLASH FLOOD WATCH SOUTHWEST...CENTRAL...AND NORTHEAST IOWA
   THIS AFTERNOON AND TONIGHT...

AT 1125 AM CDT...NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS CONTINUED
OVER NORTH CENTRAL AND NORTHEAST IOWA.

THE AREA OF SHOWERS AND THUNDERSTORMS WAS 50 MILES WIDE...CENTERED
FROM NEAR FORT DODGE...TO 30 MILES EAST OF WATERLOO.

THE HEAVIEST RAINFALL WAS IN ABOUT A 10 MILE WIDE AREA...ACROSS
SOUTHERN WEBSTER...SOUTHERN HAMILTON...AND SOUTHERN HARDIN COUNTIES...
OR FROM JUST SOUTHEAST OF FORT DODGE...TO NEAR JEWELL TO JUST SOUTHWEST
OF ELDORA.

THE SHOWERS AND THUNDERSTORMS WERE MOVING VERY SLOWLY NORTHEAST AT
AROUND 5 MILES AN HOUR.

WPM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 12:38 PM CDTFlash Flood WarningDMXCerro Gordo, Franklin3 hr

Nearby

Flash Flood Warnings in Iowa, 1990Every flash flood warning in 1990

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.