Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 21, NWS Des Moines, IA

May 17, 1991Johnson County, Iowa

NWS Des Moines, IA issued this tornado warning at May 17, 1991, 3:53 PM CDT for Johnson County, Iowa. It was in force for 37 min.

The area

The counties it named.

The facts

Issued
May 17, 1991, 3:53 PM CDT (20:53 UTC)
Expired
May 17, 1991, 4:30 PM CDT
In force
37 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Johnson County, IA

The nearest sounding before it

Minneapolis, MN (KSTC), launched 12:00Z, 8.9 hours before the alert went out and 389 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°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 172053
TORDSM
IAC103-172130-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
353 PM CDT FRI MAY 17 1991
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  430 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN EAST CENTRAL IOWA
 
   ...JOHNSON COUNTY
 
AT 350 PM CDT REPORTS OF NUMEROUS FUNNEL CLOUDS WERE REPORTED IN
EXTREME NORTHERN WASHINGTON COUNTY AND PARTS OF JOHNSON COUNTY. THE
STORM WAS MOVING NORTHEAST AT 25 TO 30 MPH. THE STORM WAS LOCATED NEAR
KALONA IOWA SOME 35 MILES SOUTH OF CEDAR RAPIDS.
 
SOME CITIES INCLUDED IN THE WARNING WERE HILLS...IOWA
CITY...CORALVILLE AND NORTH LIBERTY.
 
 
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.
 
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.

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, 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, 4:55 PM CDTTornado WarningDMXWright50 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.