Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 6, NWS Des Moines, IA

April 26, 1991Crawford County, Iowa

NWS Des Moines, IA issued this tornado warning at Apr 26, 1991, 7:49 PM CDT for Crawford County, Iowa. It was in force for 26 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 26, 1991, 7:49 PM CDT (00:49 UTC)
Expired
Apr 26, 1991, 8:15 PM CDT
In force
26 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Crawford County, IA

What was reported inside it

TimeReportWhereRemark
Apr 26, 8:00 PM CDTTornado F3Crawford, 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

Topeka, KS (KTOP), launched 00:00Z, 0.8 hours before the alert went out and 338 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, Topeka, KS 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, Topeka, KS at 00:00Z on 1991-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 409 square meters per square second.1939587897117Sfc1 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
79 kt
0-1 km storm-relative helicity
409 m²/s²
0-3 km storm-relative helicity
485 m²/s²
Significant tornado parameter
0.0
Supercell composite
17.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 270050
TORDSM
IAC047-270115-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
749 PM CDT FRI APR 26 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  815 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL IOWA
 
   ...CRAWFORD COUNTY
 
AT 745 PM...A TORNADO WAS ON THE GROUND NEAR MANILLA IN SOUTHER
CRAWFORD COUNTY. TORNADO WAS MOVING NORTHEAST 40 MILES AN HOUR.
 
OTHER TORNADO WERE SPOTTED IN THE DENISON AREA AT 748 PM.
 
PEOPLE IN THE TOWNS OF DENISON AND OTHER ADJACENT COMMUMNTIES SHOULD
BE ON THE LOOKOUT FOR SEVERE WEATHER.
 
THIS IS A DANGEROUS STORM SITUATION.  ACT QUICKLY.  IF YOU ARE
IN THE PATH OF THIS TORNADO MOVE TO A SHELTER BELOW GROUND IF
AVAILABLE.  OTHERWISE...GO TO A SMALL INTERIOR ROOM ON THE LOWEST
FLOOR POSSIBLE.  AVOID WINDOWS.  ABANDON CARS AND MOBILE HOMES
FOR A REINFORCED BUILDING OR GET INTO A DITCH OR CULVERT.
 +

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, 3:09 PM CDT, 4 hours 40 minutes before
IAZALL-262035-

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

AT 235 PM...SCATTERED SHOWERS AND THUNDERSTORMS  WERE LOCATED OVER THE
NORTHERN TWO TIERS OF IOWAS COUNTIES...FROM ESTHERVILLE TO 10 MILES
NORTHWEST OF WAUKON...WAUKON IS 60 MILES NORTHWEST OF DUBUQUE. BRIEF
HEAVY RAIN...FREQUENT DEADLY LIGHTNING AND SMALL HAIL CAN BE
EXPECTED WITH THESE STORMS.

THE SHOWERS AND STORMS WERE MOVING NORTH NORTHEAST AT 25 MILES AN HOUR.

FILLBACH/BARLOW
Special weather statement, Apr 26, 4:40 PM CDT, 3 hours 9 minutes before
IAZALL-262235-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
440 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 430 PM...THERE WAS A SMALL RAIN SHOWER LOCATED OVER WEST CENTRAL
IOWA...ABOUT 40 MILES SOUTHWEST OF SIOUX CITY.

THIS SHOWER WAS MOVING NORTHEAST AT 35 MILES AN HOUR.

THERE WILL BE OTHER SHOWERS AND THUNDERSTORM?S ENTERING WESTERN IOWA...
FROM EASTERN NEBRASKA DURING THE NEXT HOUR...BETWEEN OMAHA/COUNCIL
BLUFFS AND SIOUX CITY.

JAK/WPM
Special weather statement, Apr 26, 5:07 PM CDT, 2 hours 42 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 15 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, 1 hour 43 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 7 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

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, 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 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.