Alert archive / Iowa / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 97, NWS Sioux Falls, SD

July 6, 1994Monona County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 6, 1994, 12:14 AM CDT for Monona County, Iowa. It was in force for 46 min.

The area

The counties it named.

The facts

Issued
Jul 6, 1994, 12:14 AM CDT (05:14 UTC)
Expired
Jul 6, 1994, 1:00 AM CDT
In force
46 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Monona County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 5.2 hours before the alert went out and 88 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, Omaha, NE at 00:00Z on 1994-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3368 joules per kilogram.LCLEL10008507005003002001001 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, Omaha, NE at 00:00Z on 1994-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 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
3368 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1281 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.8
Supercell composite
8.0

Open this sounding in Storm Lab

The text

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

000 
WUUS1 KSUX 060515 RRA
SVRSUX
IAC133-060600-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
1214 AM CDT WED JUL 6 1994
 
THE NATIONAL WEATHER SERVICE IN SIOUX CITY HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  100 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL IOWA
 
   ...MONONA COUNTY
 
AT 1214 AM CDT A SEVERE THUNDERSTORM WAS LOCATED 40 TO 50 MILES
SOUTHEAST OF SIOUX CITY OR FROM MAPLETON TO BLENCOE IOWA. MOVEMENT WAS
EAST AT 25 MILES AN HOUR. THIS STORM WILL REACH SOLDIER IOWA AROUND 1245
AM CDT.
 
 
REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE DAMAGING WINDS IN EXCESS
OF 60 MPH...LARGE HAIL...DEADLY LIGHTNING...AND HEAVY RAINS THAT CAN
QUICKLY FLOOD LOW LYING AREAS. IF YOU ARE IN THE PATH OF THIS STORM
TAKE SHELTER IN A REINFORCED BUILDING IMMEDIATELY.
 
MICHELS

What forecasters said that day

The local office's own words before this severe thunderstorm 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 5, 10:06 PM CDT, 2 hours 8 minutes before
SDZ068>070-060405-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1004 PM CDT TUE JUL 5 1994

...A SEVERE THUNDERSTORM WATCH CONTINUED IN EFFECT UNTIL 2 AM CDT FOR
THE EXTREME SOUTHEAST SOUTH DAKOTA COUNTIES ALONG THE MISSOURI RIVER...

THUNDERSTORMS WERE MOVING NORTHEAST ACROSS UNION COUNTY SOUTH DAKOTA
WITH THE POTENTIAL FOR SEVERE WEATHER.

NO THUNDERSTORMS WERE OCCURRING FROM TYNDALL IN BON HOMME COUNTY ACROSS
YANKTON COUNTY TO VERMILLION IN CLAY COUNTY.  THE MOVEMENT OF THE
STORMS MAKES IT APPEAR PROBABLE THAT THUNDERSTORMS WILL PASS THEM
BY...BUT THE SEVERE THUNDERSTORM WATCH CONTINUES FOR NOW.

UMLAND
Special weather statement, Jul 5, 10:45 PM CDT, 1 hour 29 minutes before
IAZ012-060445-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1042 PM CDT TUE JUL 5 1994

THE SEVERE THUNDERSTORM WARNING FOR SIOUX COUNTY IN NORTHWEST IOWA
EXPIRED AT 1045 PM AND WILL NOT BE REISSUED AT THIS TIME.  STRONG
THUNDERSTORMS CONTINUED TO DEVELOP AND THEN DIMINISH IN INTENSITY AS
THEY MOVED NORTHEAST AT 20 MPH ACROSS THE COUNTY.  ONE OF THE STRONGEST
STORMS AT 1040 PM WAS ABOUT 40 MILES SOUTHEAST OF SIOUX FALLS NEAR
HAWARDEN IOWA.

PEOPLE IN SIOUX COUNTY SHOULD KEEP IN MIND THAT A SEVERE THUNDERSTORM
WATCH CONTINUES FOR NORTHWEST IOWA INCLUDING THEIR AREA THROUGH 2 AM.

UMLAND
Special weather statement, Jul 5, 11:01 PM CDT, 1 hour 13 minutes before
SDZ068-069-060500-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1059 PM CDT TUE JUL 5 1994

SEVERE THUNDERSTORM WATCH FOR EXTREME SOUTHEAST SOUTH DAKOTA ALONG THE
MISSOURI RIVER HAS BEEN CANCELED FOR BON HOMME AND YANKTON COUNTY
AREAS.

THE SEVERE THAUNDERSTORM WATCH DOES CONTINUE IN EFEECT FOR CLAY AND
UNION COUNTIES UNTIL 2 AM.  THUNDERSTORMS CONTINUED TO MOVE ACROSS
UNION COUNTY AND MAY YET BUILD BACK INTO CLAY COUNTY.  THESE
THUNDERSTORMS CONTINUE TO HAVE THE POTENTIAL TO PRODUCE SEVERE WEATHER.

SOME OF THESE STORMS MAY CONTAIN SMALL HAIL...GUSTY WINDS...DEADLY
LIGHTNING AND VERY HEAVY DOWNPOURS OF RAIN.

UMLAND
Special weather statement, Jul 5, 11:46 PM CDT, 28 minutes before
SDZ070-IAZ001-060600-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1150 PM CDT TUE JUL 5 1994

THE SEVERE THUNDERSTORM WATCH WHICH WAS IN EFFECT FOR THE EXTREME
SOUTHEAST SOUTH DAKOT0A COUNTIES OF CLAY AND UNION HAS BEEN CANCELED.

THERE ARE NO SEVERE THUNDERSTORM WATCHES IN EFFECT FOR ANY PART OF
SOUTH DAKOTA AS OF 1145 PM CDT.

UMLAND

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 5, 7:59 PM CDTSevere Thunderstorm WarningFSDWoodbury46 min
Jul 5, 8:37 PM CDTTornado WarningFSDWoodbury38 min
Jul 5, 8:42 PM CDTTornado WarningFSDWoodbury33 min
Jul 5, 9:18 PM CDTTornado WarningFSDWoodbury27 min
Jul 5, 9:41 PM CDTSevere Thunderstorm WarningFSDSioux64 min
Jul 5, 9:47 PM CDTTornado WarningFSDWoodbury28 min
Jul 5, 10:16 PM CDTTornado WarningFSDWoodbury29 min
Jul 5, 10:43 PM CDTSevere Thunderstorm WarningFSDPlymouth47 min
Jul 5, 11:21 PM CDTSevere Thunderstorm WarningFSDMonona, Woodbury54 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1994Every severe thunderstorm warning 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.