Alert archive / Iowa / Tornado Warnings in 1994

Tornado Warning 26, NWS Des Moines, IA

July 31, 1994Mitchell County, Iowa

NWS Des Moines, IA issued this tornado warning at Jul 31, 1994, 6:33 PM CDT for Mitchell County, Iowa. It was in force for 27 min.

The area

The counties it named.

The facts

Issued
Jul 31, 1994, 6:33 PM CDT (23:33 UTC)
Expired
Jul 31, 1994, 7:00 PM CDT
In force
27 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Mitchell County, IA

The nearest sounding before it

Minneapolis, MN (KSTC), launched 12:00Z, 11.6 hours before the alert went out and 178 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 1994-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 12:00Z on 1994-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 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
4 J/kg
Mixed-layer CIN
-306 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KALO 312335 COR
TORALO
IAC131-010000-

BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WATERLOO IA
633 PM CDT SUN JUL 31 1994

THE NATIONAL WEATHER SERVICE IN WATERLOO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  700 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN NORTH CENTRAL IOWA

   ...NORTHERN MITCHELL COUNTY

AT 630 PM CDT...A TORNADO WAS REPORTED ON THE GROUND JUST WEST OF
STACYVILLE. THE TORNADO HAD DESTROYED SOME FARM BUILDINGS...AND LIFTED
BACK INTO THE SKY. THIS TORNADO WAS LIKELY MOVING EAST SOUTHEAST AT 20
MILES AN HOUR. PERSONS IN STACYVILLE SHOULD TAKE COVER NOW.

DURING A TORNADO...THE SAFEST PLACE IS IN A BASEMENT.  GET UNDER
A WORKBENCH OR PIECE OF STURDtY FURNITURE.  IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM SUCH AS A CLOSET ON
THE LOWEST FLOOR.  AVOID WINDOWS.



DEWALD
&

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 31, 5:23 PM CDT, 1 hour 10 minutes before
IAZALL-312330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
523 PM CDT SUN JUL 31 1994

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 PM CDT FOR
NORTHERN AND CENTRAL IOWA...

AT 525 PM CDT SEVERE THUNDERSTORMS WERE MOVING ACROSS EXTREME SOUTHERN
MINNESOTA...NEAR THE IOWA BORDER.  THESE STORMS PRODUCED BASEBALL SIZED
HAIL AND WERE MOVING TO THE SOUTHEAST AT 15 MILES AN HOUR.  THE STORMS
WILL CROSS THE IOWA BORDER BY 6 PM CDT AND WILL MOVE TOWARDS THE CITIES
OF MASON CITY AND CHARLES CITY.  WEATHER SERVICE DOPPLER RADAR ALSO
SHOWED THUNDERSTORMS MOVING OVER FOREST CITY IN FLOYD COUNTY...IN NORTH
CENTRAL IOWA.  THIS STORM WAS MOVING SOUTHEAST AT 15 MILES AN HOUR.

PEOPLE IN NORTHERN AND CENTRAL IOWA SHOULD KEEP AN EYE TO THE SKY AND BE
PREPARED TO SEEK SHELTER SHOULD THREATENING WEATHER APPROACH.

FAB
Special weather statement, Jul 31, 5:24 PM CDT, 1 hour 9 minutes before
IAZALL-312330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
523 PM CDT SUN JUL 31 1994

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 PM CDT FOR
NORTHERN AND CENTRAL IOWA...

AT 525 PM CDT SEVERE THUNDERSTORMS WERE MOVING ACROSS EXTREME SOUTHERN
MINNESOTA...NEAR THE IOWA BORDER.  THESE STORMS PRODUCED BASEBALL SIZED
HAIL AND WERE MOVING TO THE SOUTHEAST AT 15 MILES AN HOUR.  THE STORMS
WILL CROSS THE IOWA BORDER BY 6 PM CDT AND WILL MOVE TOWARDS THE CITIES
OF MASON CITY AND CHARLES CITY.  WEATHER SERVICE DOPPLER RADAR ALSO
SHOWED THUNDERSTORMS MOVING OVER FOREST CITY IN FLOYD COUNTY...IN NORTH
CENTRAL IOWA.  THIS STORM WAS MOVING SOUTHEAST AT 15 MILES AN HOUR.

PEOPLE IN NORTHERN AND CENTRAL IOWA SHOULD KEEP AN EYE TO THE SKY AND BE
PREPARED TO SEEK SHELTER SHOULD THREATENING WEATHER APPROACH.

FAB
Special weather statement, Jul 31, 5:42 PM CDT, 51 minutes before
IAZALL-312345-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
5 30 PM CDT SUN JUL 31 1994

A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PORTIONS OF NORTHERN AND
CENTRAL IOWA UNTIL 10 PM THIS SUNDAY EVENING...

AT 5 30 PM CDT...THUNDERSTORMS IN NORTH CENTRAL IOWA CONTINUED TO
INCREASE IN INTENSITY.  INTENSE THUNDERSTORMS WERE LOCATED NEAR LOCATED
ABOUT 15 MILES NORTHWEST OF MASON CITY...AND ALSO ALONG THE MINNESOTA
BORDER NORTH OF OSAGE.  VERY HEAVY RAINS...STRONG GUSTY WINDS...AND
HAIL CAN BE EXPECTED WITH THE PASSAGE OF THESE STORMS.

THE STORMS WERE MOVING TO THE SOUTHEAST AT 15 MILES AN HOUR.

SCOTT
Special weather statement, Jul 31, 6:02 PM CDT, 31 minutes before
IAZALL-312330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
523 PM CDT SUN JUL 31 1994

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 PM CDT FOR
NORTHERN AND CENTRAL IOWA...

AT 525 PM CDT SEVERE THUNDERSTORMS WERE MOVING ACROSS EXTREME SOUTHERN
MINNESOTA...NEAR THE IOWA BORDER.  THESE STORMS PRODUCED BASEBALL SIZED
HAIL AND WERE MOVING TO THE SOUTHEAST AT 15 MILES AN HOUR.  THE STORMS
WILL CROSS THE IOWA BORDER BY 6 PM CDT AND WILL MOVE TOWARDS THE CITIES
OF MASON CITY AND CHARLES CITY.  WEATHER SERVICE DOPPLER RADAR ALSO
SHOWED THUNDERSTORMS MOVING OVER FOREST CITY IN FLOYD COUNTY...IN NORTH
CENTRAL IOWA.  THIS STORM WAS MOVING SOUTHEAST AT 15 MILES AN H4OUR.

PEOPLE IN NORTHERN AND CENTRAL IOWA SHOULD KEEP AN EYE TO THE SKY AND BE
PREPARED TO SEEK SHELTER SHOULD THREATENING WEATHER APPROACH.

FAB
Special weather statement, Jul 31, 6:15 PM CDT, 18 minutes before
IAZALL-010015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
615 PM CDT SUN JUL 31 1994

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR NORTHERN AND
CENTRAL IOWA UNTIL 10 PM CDT...

AT 615 PM CDT WEATHER SERVICE DOPPLER RADAR INDICATED A COUPLE OF SEVERE
THUNDERSTORMS IN NORTH CENTRAL IOWA.  ONE STORM WAS LOCATED ABOUT 5
MILES WEST OF MASON CITY AND THE OTHER STROM WAS ABOUT 25 MILES NORTH OF
MASON CITY.  THESE STORMS WERE MOVING SOUTHEAST AT 15 MILES AN HOUR AND
SHOULD ENTER MASON CITY BY 630 PM CDT.

RADAR AND SATELLITE DATA ALSO INDICATED THUNDERSTORMS DEVELOPING JUST
WEST OF SIOUX CITY IOWA AND ANOTHER BAND OF THUNDERSTORMS ABOUT 35 MILES
SOUTH OF THE DES MOINES METRO AREA.  THESE STORMS WERE ALSO MOVING TO
THE SOUTHEAST AT 15 MILES AN HOUR.

THE ATMOSPHERE IS VERY UNSTABLE OVER IOWA AND THUNDERSTORMS CAN DEVELOP
RATHER QUICKLY.  IF THREATENING WEATHER APPROACHES YOUR AREA SEEK
SHELTER IMMEDIATELY.

FAB

&
Special weather statement, Jul 31, 6:16 PM CDT, 17 minutes before
IAZALL-010015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
615 PM CDT SUN JUL 31 1994

...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR NORTHERN AND
CENTRAL IOWA UNTIL 10 PM CDT...

AT 615 PM CDT WEATHER SERVICE DOPPLER RADAR INDICATED A COUPLE OF SEVERE
THUNDERSTORMS IN NORTH CENTRAL IOWA.  ONE STORM WAS LOCATED ABOUT 5
MILES WEST OF MASON CITY AND THE OTHER STROM WAS ABOUT 25 MILES NORTH OF
MASON CITY.  THESE STORMS WERE MOVING SOUTHEAST AT 15 MILES AN HOUR AND
SHOULD ENTER MASON CITY BY 630 PM CDT.

RADAR AND SATELLITE DATA ALSO INDICATED THUNDERSTORMS DEVELOPING JUST
WEST OF SIOUX CITY IOWA AND ANOTHER BAND OF THUNDERSTORMS ABOUT 35 MILES
SOUTH OF THE DES MOINES METRO AREA.  THESE STORMS WERE ALSO MOVING TO
THE SOUTHEAST AT 15 MILES AN HOUR.

THE ATMOSPHERE IS VERY UNSTABLE OVER IOWA AND THUNDERSTORMS CAN DEVELOP
RATHER QUICKLY.  IF THREATENING WEATHER APPROACHES YOUR AREA SEEK
SHELTER IMMEDIATELYN.

FAB

&

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 7:55 AM CDTSevere Thunderstorm WarningDMXMitchell35 min
Jul 31, 4:54 PM CDTSevere Thunderstorm WarningDMXWinnebago36 min
Jul 31, 5:26 PM CDTSevere Thunderstorm WarningDMXMitchell34 min
Jul 31, 5:31 PM CDTSevere Thunderstorm WarningDMXWinnebago29 min
Jul 31, 6:02 PM CDTSevere Thunderstorm WarningDMXHancock28 min
Jul 31, 6:16 PM CDTSevere Thunderstorm WarningDMXMitchell, Worth44 min
Jul 31, 6:41 PM CDTSevere Thunderstorm WarningDMXHancock, Winnebago34 min

Nearby

Tornado Warnings in Iowa, 1994Every tornado warning in 1994Tornadoes in 1994

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.