Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 23, NWS Des Moines, IA

May 17, 1991Wright County, Iowa

NWS Des Moines, IA issued this tornado warning at May 17, 1991, 4:55 PM CDT for Wright County, Iowa. It was in force for 50 min.

The area

The counties it named.

The facts

Issued
May 17, 1991, 4:55 PM CDT (21:55 UTC)
Expired
May 17, 1991, 5:45 PM CDT
In force
50 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Wright County, IA

The nearest sounding before it

Minneapolis, MN (KSTC), launched 12:00Z, 9.9 hours before the alert went out and 236 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 1991-05-17Temperature 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 1991-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 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
NaN m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
49 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 172156
TORDSM
IAC197-172245-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
455 PM CDT FRI MAY 17 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  545 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTH CENTRAL IOWA
 
   ...WRIGHT COUNTY
 
AT 455 PM CDT A TORNADO WAS REPORTED SOUTHEAST OF CLARION IOWA MOVING
NORTHEAST AT 15 TO 20 MILES AN HOUR. CLARION SOME 30 MILES NORTHEAST
OF FORT DODGE.
 
SOME CITIES INCLUDED ARE CLARION...ROWAN...GAIT AND BELMOND.
 
 
 
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.

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, May 17, 2:45 PM CDT, 2 hours 10 minutes before
IAZ002-003-007-172130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
245 PM CDT FRI MAY 17 1991

...TORNADO WATCH FOR MUCH OF EASTERN IOWA UNTIL 900 PM...

AT 230 PM CDT VERY STRONG THUNDERSTORMS HAVE DEVELOPED RAPIDLY SINCE
200 PM IN PARTS OF NORTHEAST IOWA.  THESE STORMS WERE IN 15 MILE WIDE
AREA FROM 15 MILES SOUTH OF WATERLOO NEAR HUDSON...TO 40 MILES
NORTHWEST OF WATERLOO NEAR HAMPTON.  THESE STROMS MAY PRODUCE HEAVY
RAIN...LARGE HAIL...STRONG WINDS AND FREQUENT DANGEROUS LIGHTNING.
THESE STORMS WILL BE MOVING INTO THE WATERLOO/CEDAR FALLS...
PARKERSBURG AND DUMNONT AREA BY 300 PM.

A LARGER AREA AREA OF SHOWERS AND SCATTERED THUNDERSTORMS WAS SOUTH
OF A LINE FROM THE MINNESOTA BORDER NORTHWEST OF MASON CITY NEAR
BUFFALO CENTER...TO 15 MILES SOUTH OF CEDAR RAPIDS. THIS AREA OF
SHOWERS AND THUNDERSTORMS WERE MOVING TO THE NORTH AT 15 MILES AN
HOUR.

MG
Special weather statement, May 17, 2:49 PM CDT, 2 hours 6 minutes before
IAZ002-003-007-172130-

SPECIAL WEATHER STATEMENT...CORRECTION LAST PARAGRAPH
NATIONAL WEATHER SERVICE WATERLOO IA
245 PM CDT FRI MAY 17 1991

...TORNADO WATCH FOR MUCH OF EASTERN IOWA UNTIL 900 PM...

AT 230 PM CDT VERY STRONG THUNDERSTORMS HAVE DEVELOPED RAPIDLY SINCE
200 PM IN PARTS OF NORTHEAST IOWA.  THESE STORMS WERE IN 15 MILE WIDE
AREA FROM 15 MILES SOUTH OF WATERLOO NEAR HUDSON...TO 40 MILES
NORTHWEST OF WATERLOO NEAR HAMPTON.  THESE STROMS MAY PRODUCE HEAVY
RAIN...LARGE HAIL...STRONG WINDS AND FREQUENT DANGEROUS LIGHTNING.
THESE STORMS WILL BE MOVING INTO THE WATERLOO/CEDAR FALLS...
PARKERSBURG AND DUMNONT AREA BY 300 PM.

A LARGER AREA OF SHOWERS AND SCATTERED THUNDERSTORMS WAS SOUTH
OF A LINE FROM THE MINNESOTA BORDER NORTHWEST OF MASON CITY NEAR
BUFFALO CENTER...TO 15 MILES SOUTH OF CEDAR RAPIDS. THIS AREA OF
SHOWERS AND THUNDERSTORMS WAS MOVING TO THE NORTH AT 15 MILES AN
HOUR.

MG
Special weather statement, May 17, 2:50 PM CDT, 2 hours 5 minutes before
IAZALL-172030-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
245 PM CDT FRI MAY 17 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF WESTERN...CENTRAL...
   AND EASTERN IOWA...UNTIL 9PM THIS FRIDAY EVENING...

...GOLF BALL SIZE HAIL WAS REPORTED AT WEBSTER CITY AT AROUND 215 PM
   ...WEBSTER CITY IS ABOUT 50 MILES SOUTHWEST OF MASON CITY.

AT 235 PM CDT...INTENSE THUNDERSTORMS WERE LOCATED OVER NORTH CENTRAL
AND WEST CENTRAL IOWA.  THE STRONGEST STORMS WERE LOCATED NEAR CLARION...
OR 40 MILES SOUTHWEST OF MASON CITY...AND JUST SOUTHWEST OF COON RAPIDS
...OR 50 MILES NORTHWEST OF DES MOINES.

THESE STORMS HAVE PRODUCED EXTREMELY HEAVY RAIN...FREQUENT DANGEROUS
LIGHTNING...GUSTY WIND...AND GOLFBALL SIZE HAIL.

OVER THE REMAINDER OF NORTHERN AND EASTERN IOWA...SCATTERED SHOWERS
AND THUNDERSTORMS CONTINUE TO DEVELOP.

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

SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO SEEK SHELTER
IMMEDIATELY.

WPM/JAK
Special weather statement, May 17, 3:20 PM CDT, 1 hour 35 minutes before
IAZALL-172030-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
315 PM CDT FRI MAY 17 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF WESTERN...CENTRAL...
   AND EASTERN IOWA...UNTIL 9PM THIS FRIDAY EVENING...

SCATTERED INTENSE THUNDERSTORMS CONTINUE TO DEVELOP IN ABOUT A 20 MILE
WIDE AREA...FROM EAST CENTRAL INTO NORTHEAST AND NORTH CENTRAL IOWA.

THESE INTENSE STORMS WERE LOCATED FROM NEAR CONESVILLE...45 MILES  WEST
OF DAVENPORT...TO WATERLOO...TO 70 MILES SOUTHWEST OF MASON CITY...NEAR
GILMORE CITY.  ANOTHER SMALL AREA OF INTENSE STORMS WAS LOCATED BETWEEN
OGDEN...JEFFERSON...AND COON RAPIDS...OR 45 MILES THROUGH 65 MILES
NORTHWEST OF DES MOINES.

THESE INTENSE STORMS...ALONG WITH EXTREMELY LARGE AMOUNTS OF RAIN...
HAVE PRODUCED 1 INCH OR LARGER HAIL...STRONG GUSTY WIND...FREQUENT
DANGEROUS LIGHTNING.

THESE STORMS WERE MOVING NORTH A 15 MILES AN HOUR.

SHOULD THREATENING WEATHER APPROACH...BE PREPARERD TO SEEK SHELTER
IMMEDIATELY.

WPM/JAK
Special weather statement, May 17, 4:03 PM CDT, 52 minutes before
IAZALL-172130-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
355 PM CDT FRI MAY 17 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF IOWA UNTIL 9PM CDT
   THIS FRIDAY EVENING...

AT 335 PM CDT...NUMEROUS INTENSE THUNDERSTORMS CONTINUED...FROM EXTREME
EAST CENTRAL...INTO NORTHEAST...AND NORTH CENTRAL IOWA.

MOST OF THESE INTENSE STORMS WERE LOCATED IN ABOUT A 25 MILE WIDE AREA
FROM JUST NORTHWEST OF DAVENPORT..TO NEAR IOWA CITY....CEDAR RAPIDS...
WATERLOO...TO 35 MILES SOUTH OF MASON CITY...TO NEAR GILMORE CITY...OR
70 MILES SOUTHWEST OF MASON CITY.  ANOTHER SMALL AREA OF INTENSE STORMS
WAS LOCATED FROM 45 MILES NORTHWEST OF DES MOINES TO 55 MILES NORTHWEST
OF DES MOINES...OR FROM JUST NORTHWEST OF BOONE TO JUST NORTHEAST OF
COON RAPIDS.

THESE STORMS HAVE BEEN PRODUCING VERY LARGE AMOUNTS OF RAIN...LARGE
HAIL...SOME THE SIZE OF BASEBALLS...FREQUENT DANGEROUS LIGHTNING...
AND STRONG GUSTY WIND.

THE STORMS WERE MOVING NORTHEAST AT 10 TO 15 MILES AN HOUR.

SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO SEEK SHELTER
IMMEDIATELY.

WPM/JAK
Special weather statement, May 17, 4:54 PM CDT, 1 minute before
IAZALL-172230-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
452 PM CDT FRI MAY 17 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF IOWA UNTIL 9PM CDT
   THIS FRIDAY EVENING...

AT 432 PM CDT...SCATTERED SHOWERS AND ISOLATED INTENSE THUNDERSTORMS
WERE LOCATED OVER MUCH OF IOWA.  THE STRONGEST STORMS WERE LOCATED FROM
25 MILES SOUTHWEST TO 15 MILES SOUTHEAST OF FORT DODGE...20 MILES
NORTHEAST OF WATERLOO...40 MILES SOUTHWEST OF CEDAR RAPIDS...AND 30
MILES SOUTH OF OTTUMWA.  THESE STORMS HAVE BEEN PRODUCING VERY LARGE
AMOUNTS OF RAIN...LARGE HAIL...AN INCH AND LARGER IN DIAMETER...FREQUENT
DEADLY LIGHTNING AND GUSTY WINDS.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 35 MILES AN HOUR.

SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO TAKE SHELTER
IMMEDIATELY.

WS/JAK

The office that day

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

IssuedProductOfficeCountiesLasted
May 17, 1:54 PM CDTSevere Thunderstorm WarningDMXWright36 min
May 17, 2:05 PM CDTTornado WarningDMXHamilton, Wright25 min
May 17, 2:35 PM CDTSevere Thunderstorm WarningDMXWright40 min
May 17, 3:01 PM CDTSevere Thunderstorm WarningDMXGreene44 min
May 17, 3:17 PM CDTSevere Thunderstorm WarningDMXBlack Hawk58 min
May 17, 3:53 PM CDTTornado WarningDMXJohnson37 min
May 17, 4:12 PM CDTTornado WarningDMXHamilton, Webster33 min
May 17, 4:16 PM CDTSevere Thunderstorm WarningDMXAppanoose, Davis44 min
May 17, 4:22 PM CDTSevere Thunderstorm WarningDMXFloyd38 min
May 17, 4:22 PM CDTSevere Thunderstorm WarningDMXButler, Grundy68 min
May 17, 5:14 PM CDTSevere Thunderstorm WarningDMXBenton, Iowa46 min
May 17, 5:27 PM CDTSevere Thunderstorm WarningDMXVan Buren48 min
May 17, 5:36 PM CDTSevere Thunderstorm WarningDMXIowa, Johnson, Linn69 min
May 17, 5:45 PM CDTFlash Flood WarningDMXHamilton, Hardin, Humboldt, Webster, Wright4 hr

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; the sounding from the Mesonet's radiosonde archive.