Alert archive / Iowa / Tornado Warnings in 1991

Tornado Warning 28, NWS Des Moines, IA

July 17, 1991Howard County, Iowa

NWS Des Moines, IA issued this tornado warning at Jul 17, 1991, 9:45 PM CDT for Howard County, Iowa. It was in force for 30 min.

The area

The counties it named.

The facts

Issued
Jul 17, 1991, 9:45 PM CDT (02:45 UTC)
Expired
Jul 17, 1991, 10:15 PM CDT
In force
30 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Howard County, IA

The nearest sounding before it

Minneapolis, MN (KSTC), launched 00:00Z, 2.8 hours before the alert went out and 195 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 1991-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1083 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 1991-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
1083 J/kg
Mixed-layer CIN
-159 J/kg
Mixed-layer LCL
1349 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
61 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KALO 180244
TORALO
IAC089-180315-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WATERLOO IA
945 PM CDT WED JUL 17 1991
 
THE NATIONAL WEATHER SERVICE IN WATERLOO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL 1015 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTHEAST IOWA
 
   ...HOWARD COUNTY
 
AT 940 PM CDT A FUNNEL CLOUD WAS REPORTED 5 MILES SOUTH OF CHESTER OR 25
MILES WEST OF DECORAH.
 
CITIES IN THE PATH OF THIS FUNNEL CLOUD ARE LIME SPRINGS AND CRESCO.
 
NO MOVEMENT WAS REPORTED ON THIS TORNADO.
 
 
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 I(NTERIOR ROOM SUCH AS A CLOSET ON
THE LOWEST FLOOR.  AVOID WINDOWS.
 
COLLAR

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, Jul 17, 5:18 PM CDT, 4 hours 27 minutes before
IAZ002-003-007-182315-

SPECIAL WEATHER STATEMENT AND WEATHER UPDATE FOR NORTHEAST IOWA
NATIONAL WEATHER SERVICE WATERLOO IA
520 PM CDT WED JUL 17 1991

AT 515 PM CDT WEATHER RADAR FROM WATERLOO WAS SHOWING AN ISOLATED
STRONG THUNDERSTORM 15 MILES NORTHWEST OF MASON CITY BETWEEN FOREST
CITY AND LAKE MILLS. THIS STORM WAS NEWLY DEVELOPED AND MOVEMENT HAS
YET TO BE DETERMINED. THIS STORM WILL LIKELY PRODUCE BRIEF HEAVY RAINS
...DEADLY LIGHTNING AND POSSIBLY SOME SMALL HAIL. OTHERWISE SKIES WERE
PARTLY SUNNY WITH HOT AND HUMID CONDITIONS. TEMPERATURES WERE IN THE
LOWER TO MIDDLE 90S WITH SOUTHWEST WINDS OF 10 TO 20 MILES AN HOUR.

THROUGH 615 PM CDT SCATTERED THUNDERSTORMS WILL BE POSSIBLE ANYWHERE
OVER THE AREA...HOWEVER THE BEST CHANCES APPEAR TO BE TO THE NORTH OF
HIGHWAY 18. IT WILL CONTINUE HOT AND HUMID WITH TEMPERATURES IN THE
90S.

COLLAR

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.