Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 27, NWS Des Moines, IA

June 18, 1991Chickasaw County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 18, 1991, 9:00 PM CDT for Chickasaw County, Iowa. It was in force for 45 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
Jun 18, 1991, 9:00 PM CDT (02:00 UTC)
Expired
Jun 18, 1991, 9:45 PM CDT
In force
45 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Chickasaw County, IA

What was reported inside it

TimeReportWhereRemark
Jun 18, 9:10 PM CDTTornado F1Chickasaw, 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, 2.0 hours before the alert went out and 224 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 1991-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 199 joules per kilogram.LCLLFCEL10008507005003002001001 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 1991-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 square meters per square second.193958Sfc1 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
199 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
1675 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KALO 190206
TORALO
IAC037-190245-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WATERLOO IA
900 PM CDT TUE JUN 18 1991
 
THE NATIONAL WEATHER SERVICE IN WATERLOO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  945 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTHEAST IOWA
 
   ...CHICKASAW COUNTY
 
AT 900 PM CDT WEATHER SERVICE RADAR HAS INDICATED A TORNADOE 6 MILES
NORTH OF NEW HAMPTON. THIS TORNADOE WAS MOVING SOUTH AT 20 MILES AN
HOUR. CITIES IN THE PATH OF THIS TORNADOE PRODUCING STORM ARE NEW
HAMPTON.
 
DURING A TORNADO...THE SAFEST PLACE IS IN 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.  AVOID WINDOWS.
 
 
THIS IS A DANGEROUS STORM SITUATION.  ACT QUICKLY.  YOU SHOULD
SEEK SHELTER BELOW GROUND LEVEL IF POSSIBLE.  OTHERWISE...GO TO A
SMALL INTERIOR ROOM ON THE LOWEST FLOOR POSSIBLE AND AVOID WINDOWS.
 
 
SPEECE/GOODSON

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, Jun 18, 8:36 PM CDT, 24 minutes before
IAZALL-190235-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
835 PM CDT TUE JUN 18 1991

AT 827 PM...AN ISOLATED VERY STRONG THUNDERSTORM WAS OCCURRING IN
NORTHEAST IOWA...45 MILES NORTH OF WATERLOO...OR JUST SOUTHWEST OF
CRESCO.  THIS STORM WAS PRODUCING VERY HEAVY RAIN...GUSTY WINDS AND
POSSIBLY SOME HAIL.

AN ISOLATED SHOWER WAS ALSO 40 MILES WEST OF WATERLOO...OR JUST SOUTH
OF IOWA FALLS.

THE SHOWERS AND STORMS WERE MOVING SOUTH AT AROUND 10 MILES AN HOUR.

JAK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 18, 7:45 PM CDTSevere Thunderstorm WarningDMXHoward60 min
Jun 18, 8:47 PM CDTSevere Thunderstorm WarningDMXChickasaw, Fayette, Howard, Winneshiek58 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.