Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 7, NWS Des Moines, IA

April 26, 1991Sac County, Iowa

NWS Des Moines, IA issued this tornado warning at Apr 26, 1991, 8:19 PM CDT for Sac County, Iowa. It was in force for 56 min. 2 reports 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 26, 1991, 8:19 PM CDT (01:19 UTC)
Expired
Apr 26, 1991, 9:15 PM CDT
In force
56 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Sac County, IA

What was reported inside it

TimeReportWhereRemark
Apr 26, 8:20 PM CDTHail 1.75Sac, IA
Apr 26, 8:30 PM CDTThunderstorm Wind 70Sac, 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, 1.3 hours before the alert went out and 300 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 270120
TORDSM
IAC161-270145-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
819 PM CDT FRI APR 26 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  845 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL IOWA
 
   ...SOUTHEASTERN SAC COUNTY
 
A POSSIBLE TORNADO WAS ON THE GROUND NEAR LAKE VIEW WHICH IS 75 MILES
NORTHWEST OF DES MOINES INJ WEST CENTRAL IOWA. THE TORNADO WAS MOVING
NORTHEAST AT 40 MILES AN HOUR. PEOPLE IN THE TOWNS OF WALL LAKE...LAKE
VIEW...CARNARVON AND SAC CITY ARE IN THE DIRECT PATH OF THIS TORNADO.
 
 
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, Apr 26, 5:07 PM CDT, 3 hours 12 minutes before
IAZALL-262235-

SPECIAL WEATHER STATEMENT AND IOWA WEATHER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
508 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR PORTIONS OF WESTERN IOWA
   UNTIL 10 PM CDT THIS FRIDAY EVENING.

WIDELY SCATTERED RAIN SHOWERS CONTINUED TO SPREAD INTO SOUTHWEST
AND WEST CENTRAL IOWA.

THESE SHOWERS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

THE OUTLOOK THROUGH 6PM...THE SKY WILL REMAIN CLOUDY TO MOSTLYn
CLOUDY STATEWIDE.  SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
SPREAD INTO SOUTHWEST AND WEST CENTRAL IOWA.  SOME OF THESE STORMS
COULD PRODUCE SOME SMALL HAIL AND BRIEF STRONG GUSTY WIND...AS WELL
AS FREQUENT DANGEROUS LIGHTNING.

JAK/WPM
Special weather statement, Apr 26, 5:34 PM CDT, 2 hours 45 minutes before
IAZALL-262335-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
534 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR PORTIONS OF WESTERN IOWA
   UNTIL 10 PM CDT THIS FRIDAY EVENING.

AT 527 PM CDT...SCATTERED SHOWERS CONTINUED OVER EXTREME WEST
CENTRAL IOWA...BETWEEN COUNCIL BLUFFS/OMAHA AND SIOUX CITY.

THESE SHOWERS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

JAK/WPM
Special weather statement, Apr 26, 6:06 PM CDT, 2 hours 13 minutes before
IAZALL-270035-

SPECIAL WEATHER STATEMENT AND IOWA WEATHER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
605 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MOST OF WESTERN IOWA
   UNTIL MIDNIGHT THIS FRIDAY EVENING.

NUMEROUS SHOWERS CONTINUED OVER WEST CENTRAL IOWA...IN A 45 MILE
WIDE AREA...CENTERED FROM 40 MILES SOUTHEAST OF SIOUX CITY...
TO 15 MILES NORTH OF COUNCIL BLUFFS.

THESE SHOWERS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

THE OUTLOOK THROUGH 7 PM...IS FOR CONTINUED INCREASING COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER ABOUT THE WEST ONE-THIRD OF IOWA.
THE SKY WILL REMAIN MOSTLY CLOUDY STATEWIDE.

JAK/WPM
Special weather statement, Apr 26, 6:42 PM CDT, 1 hour 37 minutes before
IAZALL-270135-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
740 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MOST OF WESTERN IOWA
   UNTIL MIDNIGHT THIS FRIDAY EVENING.

AT 727 PM CDT...VERY STRONG THUNDERSTORMS HAVE DEVELOPED RAPIDLY
OVER WEST CENTRAL IOWA.  THE STRONGEST STORMS WERE LOCATED IN
ABOUT A 20 MILE WIDE AREA...CENTERED FROM NEAR ADAIR...OR 50 MILES
WEST OF DES MOINES...TO NEAR MANILLA...OR 50 MILES NORTHEAST OF
COUNCIL BLUFFS...TO JUST NORTH OF COUNCIL BLUFFS.

THESE STORMS...ALONG WITH BRIEF VERY HEAVY RAINFALL...HAVE BEEN
PRODUCING SOME LARGE HAIL...FREQUENT DANGEROUS LIGHTNING...AND
COULD ALSO PRODUCE BRIEF STRONG GUSTY WIND.

THE STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.
.
PEOPLE IN THE PATH OF THESE STORMS SHOULD BE PREPARED TO SEEK
SHELTER IMMEDIATELY IF THREATENING WEATHER APPROACHES.

JAK/WPM
Special weather statement, Apr 26, 7:51 PM CDT, 28 minutes before
IAZALL-270135-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
750 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MOST OF WESTERN IOWA
   UNTIL MIDNIGHT THIS FRIDAY EVENING.

AT 727 PM CDT...INTENSE THUNDERSTORMS WERE LOCATED OVER EXTREME WEST
CENTRAL IOWA...IN A 10 MILE WIDE AREA...FROM NEAR MAPLETON...30 MILES
SOUTHEAST OF SIOUX CITY...TO JUST NORTH OF COUNCIL BLUFFS.

THESE INTENSE STORMS...WERE PRODUCING BRIEF VERY HEAVY RAIN...
FREQUENT DANGEROUS LIGHTNING...AND COULD ALSO PRODUCE SOME LARGE
HAIL AND STRONG GUSTY WIND.

OVER THE REMAINDER OF ABOUT THE WEST HALF OF IOWA...NUMEROUST SHOWERS
AND STRONG THUNDERSTORMS CONTINUED TO DEVELOP.

THE STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.
PEOPLE IN THE PATH OF THESE NUMEROUS STRONG THUNDERSTORMS
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING CONDITIONS...AND
BE PREPARED TO SEEK SHELTER IMMEDIATELY SHOULD THREATENING
WEATHER APP.ROACH.

JAK/WPM
Special weather statement, Apr 26, 8:05 PM CDT, 14 minutes before
IAZALL-270200-

SPECIAL WEATHER STATEMENT AND IOWA WEAHTER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
805 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF THE WEST HALF OF
   IOWA UNTIL 2 AM SATURDAY MORNING...AND FOR EXTREME NORTHWEST
   IOWA UNTIL MIDNIGHT THIS FRIDAY EVENING...

WIDELY SCATTERED INTENSE THUNDERSTORMS CONTINUED OVER WEST CENTRAL
AND SOUTHWEST IOWA.  IN WEST CENTRAL IOWA...THE STRONGEST STORMS WERE
LOCATED IN ABOUT A 20 MILE WIDE AREA...FROM NEAR DENNISON...OR 45
MILES SOUTHWEST OF SIOUX CITY...TO NEAR SAC CITY...OR 45 MILES WEST
OF FORT DODGE.  IN SOUTHWEST IOWA...THE STRONGEST STORMS WERE LOCATED
IN ABOUT A 10 MILE WIDE BAND...CENTERED FROM JUST NORTHEAST OF VALISCA
...60 MILES SOUTHEAST OF COUNCIL BLUFFS...SOUTH TO THE IOWA/MISSOURI
BORDER.

OVER THE REMAINDER OF ABOUT THE WEST HALF OF IOWA...NUMEROUS SHOWERS
AND STRONG THUNDERSTORMS CONTINUED TO DEVELOP.

THESE STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

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

THE OUTLOOK THROUGH 9 CPM IS FOR CONTINUED STRONG THUNDERSTORMS
TO CONTINUED OVER ABOUT THE WEST HALF OF IOWA...WITH A MOSTLY
CLOUDY SKY ELSEWHERE.

JAK/WPM

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, 8:36 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 WarningDMXIowa41 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.