Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 10, NWS Des Moines, IA

April 27, 1991Iowa County, Iowa

NWS Des Moines, IA issued this tornado warning at Apr 27, 1991, 2:04 AM CDT for Iowa County, Iowa. It was in force for 41 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 27, 1991, 2:04 AM CDT (07:04 UTC)
Expired
Apr 27, 1991, 2:45 AM CDT
In force
41 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Iowa County, IA

What was reported inside it

TimeReportWhereRemark
Apr 27, 2:09 AM CDTTornado F1Iowa, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Minneapolis, MN (KSTC), launched 00:00Z, 7.1 hours before the alert went out and 373 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, Minneapolis, MN at 00:00Z on 1991-04-27Temperature 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, Minneapolis, MN at 00:00Z on 1991-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1609 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
433 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 270705
TORDSM
IAC095-105-270745-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
204 AM CDT SAT APR 27 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  245 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN EAST CENTRAL IOWA
 
   ...WESTERN IOWA COUNTY
 
IN SOUTHEAST IOWA
 
   ...NORTHWESTERN KEOKUK COUNTY
 
AT 202 AM...A TORNADO WAS REPORTED NEAR THE MAHASKA...KEOKUK COUNTY
LINE...SOME 15 MILES NORTHEAST OF OSKALOOSA OR 50 MILES SOUTHWEST OF
CEDAR RAPIDS.
 
THE STORM WAS MOVING NORTHEAST AT 45 MILES AN HOUR...AND WILL BE
AFFECTING THE CITIES OF GIBSON...THORNBURG..AND MILLERSBURG.
 
 
 
IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH OR PIECE OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIO3NS TO COVER YOUR BODY.  AVOID WINDOWS.

What forecasters said that day

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

In the hours before

Local storm report, Apr 27, 12:45 AM CDT, 1 hour 19 minutes before
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE WATERLOO IA
1245 AM CDT SAT ARP 27 1991

                                EVENT AND LOCATION
HANCOCK COUNTY
        1040PM CDT   TORNADO REPORTED TO THE WEATHER OFFICE AT 1205
                     AM CDT.
                     EXTENSIVE TREE DAMAGE IN GARNER WITH 3 TO 5
                     TRAILER HOMES TIPPED OVER AND HEAVILY DAMAGED.
                     SOME HOME DAMAGE WITH NO SERIOUS INJURIES
                     REPORTED.  EVERYONE ACCOUNTED FOR.
Special weather statement, Apr 27, 12:49 AM CDT, 1 hour 15 minutes before
IAZALL-270645-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1248 AM CDT SAT APR 27 1991

...AT 1 PM...ONLY A SEVERE THUNDERSTORM WATCH WILL REMAIN IN EFFECT
   FOR A LARGE PORTION OF SOUTHERN AND EASTERN IOWA UNTIL 4 AM...

AT 1231 AM...SHOWERS AND THUNDERSTORMS CONTINUED OVER MUCH OF THE
WEST THREE QUARTERS OF IOWA...GENERALLY WEST OF A LINE FROM OTTUMWA TO
30 MILES EAST OF WATERLOO.

WITHIN THIS AREA...SCATTERED INTENSE STORMS WERE OVER SOUTH CENTRAL AND
CENTRAL IOWA.  THE STRONGEST STORMS WERE LOCATED FROM 30 MILES SOUTHWEST
OF DES MOINES...TO 45 MILES EAST OF DES MOINES NEAR NEW SHARON...AND
45 MILES NORTHEAST OF DES MOINES NEAR GRINNELL.
.
THESE INTENSE STORMS HAVE BEEN PRODUCING VERY HEAVY RAIN AND FREQUENT
DEADLY LIGHTNING...AND POSSIBLY HAIL AND BRIEF STRONG GUSTY WIND.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

PEOPLE IN THE PATH OF THESE INTENSE THUNDERSTORMS SHOULD REMAIN ALERT
FOR RAPIDLY CHANGING CONDITIONS...AND BE PREPARED TO SEEK IMMEDIATE
SHELTER SHOULD THREATENING WEATHER APPROACH.

DM/JAK
Special weather statement, Apr 27, 1:17 AM CDT, 47 minutes before
IAZALL-270710-

SPECIAL WEATHER STATEMENT AND IOWA WEATHER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
118 AM CDT SAT APR 27 1991

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR MUCH OF THE
   SOUTHEAST QUARTER OF IOWA UNTIL 4 AM...

AT 105 AM...SHOWERS AND THUNDERSTORMS CONTINUED OVER MUCH OF THE EAST
THREE QUARTERS OF IOWA.  MOST OF THE PRECIPITATION WAS EAST OF A LINE
FROM LAMONI...TO FORT DODGE...TO 30 MILES WEST OF MASON CITY.

WITHIN THIS AREA...SCATTERED INTENSE STORMS WERE LOCATED FROM SOUTH
CENTRAL INTO NORTHEAST IOWA.  THE STRONGEST STORMS WERE OCCURRING IN A
10 MILE WIDE BAND FROM 35 MILES SOUTHWEST OF OTTUMWA NEAR CENTERVILLE...
TO 35 MILES NORTHEAST OF DES MOINES NEAR NEWTON.  OTHER STRONG STORMS
WERE LOCATED FROM 15 MILES SOUTH OF WATERLOO TO 30 MILES WEST OF CEDAR
RAPIDS.

THESE INTENSE STORMS WERE PRODUCING BRIEF HEAVY RAIN AND FREQUENT DEADLY
LIGHTNING...AND POSSIBLY SOME HAIL AND STRONG GUSTY WINDS.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

PEOPLE IN THE PATH OF THESE INTENSE THUNDERSTORMS SHOULD REMAIN ALERT
FOR RAPIDLY CHANGING CONDITIONS...AND BE PREPARED TO SEEK IMMEDIATE
SHELTER SHOULD THREATENING WEATHER APPROACH.

DM/JAK
Special weather statement, Apr 27, 1:21 AM CDT, 43 minutes before
IAZ002-003-006-007-270700-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
1215 AM CDT SAT APR 27 1991

...A SEVERE THUNDERSTORM WATCH FOR PARTS OF NORTHEAST IOWA UNITL
4AM CDT...

AT 110 AM CDT AN AREA OF VERY STRONG THUNDERSTORMS EXTENDED FROM ABOUT
10 MILES EAST OF WATERLOO TO ABOUT 15 MILES SOUTHWEST OF WATERLOO. THESE
STRONG THUNDERSTORMS WERE PART OF A LARGER AREA OF SHOWERS AND
THUNDERSTORMS IN NORTHEAST AND NORTH CENTRAL IOWA THAT WERE GENERALLY
WEST OF A LINE FROM THE MINNESOTA BORDER NORTHWEST OF DECORAH TO NEAR
INDEPENDENCE.

THESE THUNDERSTORMS WERE PRODUCING VERY HEAVY RAIN...STRONG GUSTY WINDS
AND DANGEROUS LIGHTNING AS THEY MOVE NORTHEAST AT 40 MILES AN HOUR.
Special weather statement, Apr 27, 1:45 AM CDT, 19 minutes before
IAZALL-270745-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
144 AM CDT SAT APR 27 1991

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR MUCH OF THE
   SOUTHEAST QUARTER OF IOWA UNTIL 4 AM...

AT 133 AM...SHOWERS AND THUNDERSTORMS WERE LOCATED MAINLY OVER THE EAST
HALF OF IOWA.  MOST OF THE PRECIPITATION WAS EAST OF A LINE FROM 30
MILES EAST OF LAMONI...TO FORT DODGE...TO 15 MILES WEST OF MASON CITY.

WITHIN THIS AREA...SCATTERED INTENSE STORMS WERE LOCATED IN A 20 MILE
BAND EXTENDING FROM 15 MILES WEST OF OTTUMWA NEAR ALBIA...TO JUST EAST
OF WATERLOO.

THESE INTENSE STORMS WERE PRODUCING BRIEF HEAVY RAIN AND FREQUENT DEADLY
LIGHTNING...ALONG WITH PEA TO MARBLE SIZE HAIL AND STRONG WINDS GUSTING
TO 40 MILES AN HOUR.
.
THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

PEOPLE IN THE PATH OF THESE INTENSE THUNDERSTORMS SHOULD REMAIN ALERT
FOR RAPIDLY CHANGING CONDITIONS...AND BE PREPARED TO SEEK IMMEDIATE
SHELTER SHOULD THREATENING WEATHER APPROACH.

DM/JAK
Special weather statement, Apr 27, 2:02 AM CDT, 2 minutes before
IAZ007-010-011-014-013-015-270730-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
200 AM CDT SAT APR 27 1991

AT 200 AM...A PORTION OF CENTRAL AND SOUTH CENTRAL IOWA HAS BEEN CLEARED
FROM SEVERE THUNDERSTORM WATCH 199.  COUNTIES CLEARED FROM THE WATCH
ARE...

...CENTRAL...
BOONE           DALLAS          JASPER          MARSHALL
POLK            STORY

...SOUTH CENTRAL...
CLARKE          DECATUR         LUCAS           MADISON
MARION          RINGGOLD        UNION           WARREN
WAYNE

SOME CITIES NO LONGER IN THE WATCH AREA ARE...
/
AMES            BOONE           CRESTON         DES MOINES
INDIANOLA       KNOXVILLE       MARSHALLTOWN    NEWTON
PERRY

.................................................................
A LARGE PART OF THE SOUTHEAST QUARTER AND PART OF NORTHEAST IOWA
REMAIN IN WATCH 199 HOWEVER UNTIL 4 AM.

THESE INCLUDE THE FOLLOWING COUNTIES...

...NORTH CENTRAL...
BUTLER

...NORTHEAST...
BLACK HAWK      BREMER          BUCHANAN        FAYETTE

...CENTRAL...

GRUNDY          POWESHIEK       TAMA

...EAST CENTRAL...
BENTON          IOWA            JOHNSON         LINN
/
...SOUTH CENTRAL...
APPANOOSE       MAHASKA         MONROE

...SOUTHEAST...
DAVIS           DES MOINES      HENRY           JEFFERSON
KEOKUK          LEE             LOUISA          VAN BUREN
WAPELLO         WASHINGTON

SOME CITIES STILL INCLUDED IN THE WATCH AREA ARE...

BURLINGTON      CEDAR 0RAPIDS    CENTERVILLE     FAIRFIELD
GRINNELL        INDEPENDENCE    IOWA CITY       KEOKUK
MT.PLEASANT     OELWEIN         OSKALOOSA       OTTUMWA
TAMA-TOLEDO     WASHINGTON      WATERLOO        WAVERLY

MYERS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 26, 7:43 PM CDTSevere Thunderstorm WarningDMXCrawford32 min
Apr 26, 7:49 PM CDTTornado WarningDMXCrawford26 min
Apr 26, 8:19 PM CDTTornado WarningDMXSac56 min
Apr 26, 8:36 PM CDTSevere Thunderstorm WarningDMXBuena Vista29 min
Apr 26, 8:55 PM CDTSevere Thunderstorm WarningDMXRinggold30 min
Apr 26, 9:19 PM CDTSevere Thunderstorm WarningDMXDecatur35 min
Apr 26, 9:19 PM CDTSevere Thunderstorm WarningDMXClarke41 min
Apr 26, 9:46 PM CDTSevere Thunderstorm WarningDMXPolk, Warren44 min
Apr 26, 10:59 PM CDTSevere Thunderstorm WarningDMXLucas, Wayne31 min
Apr 26, 11:18 PM CDTTornado WarningDMXWayne27 min
Apr 26, 11:23 PM CDTTornado WarningDMXLucas37 min
Apr 27, 12:02 AM CDTSevere Thunderstorm WarningDMXMahaska, Marion, Monroe28 min
Apr 27, 1:30 AM CDTSevere Thunderstorm WarningDMXMahaska45 min
Apr 27, 2:04 AM CDTTornado WarningDMXKeokuk15 min

Nearby

Tornado Warnings in Iowa, 1991Every tornado warning in 1991Tornadoes in 1991

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.