Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 32, NWS Des Moines, IA

September 12, 1991Linn County, Iowa

NWS Des Moines, IA issued this tornado warning at Sep 12, 1991, 5:01 PM CDT for Linn County, Iowa. It was in force for 24 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
Sep 12, 1991, 5:01 PM CDT (22:01 UTC)
Expired
Sep 12, 1991, 5:25 PM CDT
In force
24 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Linn County, IA

What was reported inside it

TimeReportWhereRemark
Sep 12, 5:15 PM CDTThunderstorm Wind 52Linn, 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 12:00Z, 10.0 hours before the alert went out and 348 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 12:00Z on 1991-09-12Temperature 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 12:00Z on 1991-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 square meters per square second.1939587897Sfc1 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
556 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
36 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 122202
TORDSM
IAC113-122230-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
501 PM CDT THU SEP 12 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  530 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN EAST CENTRAL IOWA
 
   ...SOUTHERN LINN COUNTY
 
AT 459 PM SEVERAL TORNADOES WERE REPORTED ON THE GROUND IN THE SOUTHWEST
SECTIONS OF CEDAR RAPIDS.
 
THESE TORNADOES WERE MOVING TO THE EAST AT 50 MILES AN HOUR.  SOME OF
THE CITIES IN THE PATH OF THE STORM ARE CEDAR RAPIDS...BERTRAM AND
MOUNT VERNON.
 
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 CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.
WEINBRECHT

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

Special weather statement, Sep 12, 2:47 PM CDT, 2 hours 14 minutes before
IAZALL-122045-

SPECIAL WEATER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
248 PM CDT THU SEP 12 1991

...A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 9 PM CDT FOR MUCH OF
CENTRAL AND EASTERN IOWA.

AT 232 PM...AN INTENSE THUNDERSTORM 10 MILES IN DIAMETER WAS 35 MILES
NORTH OF DES MOINES JUST NORTHEAST OF BOONE.  TORRENTIAL RAIN AND STRONG
WINDS CAN BE EXPECTED NEAR THIS STORM.  WINDS GUSTING TO 40 MPH WERE
REPORTED AT BOONE AT 230 PM.

THIS STORM WAS WITH A 10 MILE-WIDE BAND OF STRONG STORMS FROM 30 MILES
NORTHWEST OF DES MOINES TO JUST SOUTHEAST OF STORY CITY.  OTHER SHOWERS
WERE SCATTERED IN AN AREA 60 MILES WIDE NORTHWEST OF A LINE FROM NEAR
REDFIELD TO ELDORA.

MOVEMENT WAS EAST AT 35 MILES AN HOUR.
/
BURKE
Special weather statement, Sep 12, 3:19 PM CDT, 1 hour 42 minutes before
IAZALL-122015-

SPECIAL WEATHER STATEMENT AND WEATHER UPDATE FOR IOWA
NATIONAL WEATHER SERVICE DES MOINES IA
315 PM CDT THU SEP 12 1991

...A SEVERE THUNDERSTORM WATCH FOR MUCH OF CENTRAL AND EASTERN IOWA
UNTIL 9PM...

AT 305 PM CDT...INTENSE THUNDERSTORMS WERE LOCATED OVER CENTRAL IOWA.
THE FIRST STORM WAS LOCATED 35 MILES NORTH NORTHEAST OF DES MOINES...
NEAR NEVADA. THIS STORM COULD PRODUCE EXTREMELY HEAVY RAIN...DAMAGING
THUNDERSTORMS WINDS AND FREQUENT DEADLY LIGHTNING. THE SECOND INTENSE
STORM WAS LOCATED IN THE NORTHWEST SUBURBS OF DES MOINES. THIS STORM
COULD ALSO PRODUCE EXTREMELY HEAVY RAINS AND DAMAGING THUNDERSTORM
WINDS ALONG WITH DEADLY LIGHTNING.

THESE STORMS WERE PART OF AN EXPANDING AREA OF SHOWERS AND STORMS
THAT EXTENDED FROM DES MOINES NORTH TO MASON CITY. THE LEADING EDGE OF
THIS AREA EXTENDED FROM DES MOINES NORTHEAST TO CHARLES CITY.

THE SHOWERS AND STORMS WERE MOVING EAST AT 30 TO 35 MILES AN HOUR.

THE O`UTLOOK THROUGH 4PM...THE AREA OF SHOWERS AND STORMS WILL CONTINUE
AN EASTWARD MOVEMENT...HOWEVER SOUTHWARD DEVELOPMENT ON THIS AREA OF
THUNDERSTORMS.

BARLOW/MILLER
Special weather statement, Sep 12, 3:22 PM CDT, 1 hour 39 minutes before
IAZ002-003-007-122100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
310 PM CDT THU SEP 12 1991

...SEVERE THUNDERSTORM WATCH FOR PARTS OF NORTHEAST IOWA UNTIL
900 PM CDT...

AT 305 PM THUNDERSTORMS WERE LOCATED IN NORTH CENTRAL AND NORTHEAST
IOWA GENERALLY WEST OF A LINE FROM NEW HAMPTON...ABOUT 30 MILES NORTH
OF WATERLOO...TO REINBECK...15 MILES SOUTHWEST OF WATERLOO. THE
STRONGEST STORM WAS LOCATED ABOUT 15 MILES NORTHWEST OF WATERLOO. THE
THUNDERSTORMS WERE MOVING EAST AT 35 MILES AN HOUR.

OTHER INTENSE THUNDERSTORMS WERE LOCATED IN CENTRAL IOWA.

THE THUNDERSTORMS WILL MOVE INTO THE WAVERLY AREA BY 330 PM AND INTO
THE WATERLOO/CEDAR FALLS AREA BY 400 PM. YOU SHOULD BE ALERT TO VERY
HEAVY RAIN...SMALL HAIL AND STRONG GUSTY WINDS AS THESE STORMS MOVE
INTO YOUR AREA.
Special weather statement, Sep 12, 4:34 PM CDT, 27 minutes before
IAZ002-003-007-122200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
420 PM CDT THU SEP 12 1991

...SEVERE THUNDERSTORM WATCH FOR PARTS OF NORTHEAST IOWA UNTIL
900 PM CDT...

AT 415 PM INTENSE THUNDERSTORMS WERE LOCATED IN NORTHEAST IOWA FROM
NEAR WAVERLY...10 MILES NORTH OF WATERLOO TO NEAR LA PORTE CITY...
ABOUT 10 MILES SOUTHEAST OF WATERLOO. THESE THUNDERSTORMS WERE MOVING
EAST AT 40 MILES AN HOUR.

THESE THUNDERSTORM WILL BE MOVING INTO BUCHANAN COUNTY BY 500 PM.
PEOPLE IN EASTERN BLACKHAWK AND SOUTHEAST BREMER COUNTY SHOULD BE ALERT
FOR LARGE HAIL...STRONG DAMAGING WINDS AND BRIEF HWAVY RAIN AS THESE
STORMS MOVE THROUGH THEIR AREA.

OTHER SCATTERED SHOWERS AND THUNDERSTORMS CONTINUED IN NORTHEAST IOWA
GENERALLY WEST OF A LINE FROM LA PORTE CITY TO FAYETTE.
Special weather statement, Sep 12, 4:39 PM CDT, 22 minutes before
IAZALL-122135-

SPECIAL WEATER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
436 PM CDT THU SEP 12 1991

...A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 9 PM CDT FOR MUCH OF
CENTRAL AND EASTERN IOWA.

AT 430 PM...20 MILE WIDE BAND OF INTENSE THUNDERSTORMS EXTENDED FROM
10 MILES SOUTHEAST OF WATERLOO SOUTH INTO SOUTH CENTRAL BENTON COUNTY
THEN SOUTHWEST TO NEAR GRINNELL. THIS BAND OF VERY POWERFULL STORMS
WAS MOVING EAST AT 60 MILES AN HOUR. PEOPLE IN THE PATH OF THIS CLUSTER
OF STORMS SHOULD MOVE TO A PLACE OF SHELTER AS THIS BAND APPROACHES.

THESE THUNDERSTORMS WERE PART OF A 60 MILE WIDE BAND OF SHOWERS AND
STORMS THAT EXTENDED FROM NEW HAMPTON...IN NORTHEAST IOWA...SOUTHWEST
TO 5 MILES NORTHEAST OF PELLA.

A SMALL CLUSTER OF SHOWERS AND ISOLATED THUNDERSTORMS WAS LOCATED OVER
NORTHWEST IOWA AROUND CHEROKEE...STORM LAKE...POCOHONTAS AND GILMORE
CITY. THESE SHOWERS AND STORMS WERE MOVING EAST AT 30 MILES AN MHOUR.

BARLOW/MARTIN
Special weather statement, Sep 12, 4:54 PM CDT, 7 minutes before
IAZALL-120200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
453 PM CDT THU SEP 12 1991

A PORTION OF THE SEVERE THUNDERSTORM WATCH...NUMBER 770...HAS BEEN
CANCELED.  THE FOLLOWING COUNTIES ARE CLEARED FROM THE WATCH...

FRANKLIN        HUMBOLDT        WRIGHT
BOONE           DALLAS          HAMILTON        HARDIN
JASPER          MARSHALL        POLK            STORY
WEBSTER         MADISON         MARION          WARREN

SOME CITIES CLEARED ARE...

AMES            BOONE           DES MOINES      FORT DODGE
INDIANOLA       IOWA FALLS      KNOXVILLE       MARSHALLTOWN
NEWTON          PERRY           WEBSTER CITY

THE WATCH REMAINS IN EFFECT FOR MUCH OF EASTERN IOWA.  THE FOLLOWING
COUNTIES REMAIN IN THE SEVERE THUNDERSTORM WATCH...

BUTLER          CLAYTON         FAYETTE         SCOTT
BREMER          GRUNDY          POWESHIEK       TAMA
BENTON          BLACK HAWK      BUCHANAN        CEDAR
CLINTON         DELAWARE        DUBUQUE         IOWA
JACKSON         JOHNSON         JONES           LINN
APPANOOSE       MAHASKA         MONROE
DAVIS           DES MOINES      HENRY           JEFFERSON
KEOKUK          LEE             LOUISA          MUSCATINE
VAN BUREN       WAPELLO         WASHINGTON

SOME CITIES REMAINING IN THE WATCH ARE...

BURLINGTON      CEDAR RAPIDS    CENTERVILLE     CLINTON
DAVENPORT       DUBUQUE         FAIRFIELD       GRINNELL
INDEPENDENCE    IOWA CITY       KEOKUK          MAQUOKETA
MT. PLEASANT    MUSCATINE       OELWEIN         OSKALOOSA
OTTUMWA         TAMA-TOLEDO     WASHINGTON      WATERLOO
WAVERLY

MS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 7:41 PM CDTSevere Thunderstorm WarningDMXCarroll, Greene34 min
Sep 11, 8:08 PM CDTSevere Thunderstorm WarningDMXHamilton52 min
Sep 11, 8:08 PM CDTSevere Thunderstorm WarningDMXWebster45 min
Sep 11, 8:22 PM CDTSevere Thunderstorm WarningDMXGreene31 min
Sep 11, 8:22 PM CDTSevere Thunderstorm WarningDMXBoone, Story53 min
Sep 12, 3:03 PM CDTSevere Thunderstorm WarningDMXMarshall, Story29 min
Sep 12, 3:20 PM CDTSevere Thunderstorm WarningDMXPolk25 min
Sep 12, 3:33 PM CDTSevere Thunderstorm WarningDMXMarshall, Tama42 min
Sep 12, 3:44 PM CDTSevere Thunderstorm WarningDMXJasper31 min
Sep 12, 3:53 PM CDTSevere Thunderstorm WarningDMXBlack Hawk61 min
Sep 12, 3:53 PM CDTSevere Thunderstorm WarningDMXGrundy31 min
Sep 12, 4:19 PM CDTTornado WarningDMXBenton26 min
Sep 12, 4:19 PM CDTTornado WarningDMXTama19 min
Sep 12, 4:41 PM CDTSevere Thunderstorm WarningDMXLinn49 min
Sep 12, 4:58 PM CDTTornado WarningDMXJohnson32 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.