Alert archive / Minnesota / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 115, NWS Twin Cities, MN

July 21, 1991Big Stone County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 21, 1991, 6:32 PM CDT for Big Stone County, Minnesota. It was in force for 58 min.

The area

The counties it named.

The facts

Issued
Jul 21, 1991, 6:32 PM CDT (23:32 UTC)
Expired
Jul 21, 1991, 7:30 PM CDT
In force
58 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Big Stone County, MN

The nearest sounding before it

Aberdeen, SD (KHON), launched 12:00Z, 11.5 hours before the alert went out and 167 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, Aberdeen, SD at 12:00Z on 1991-07-21Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 12:00Z on 1991-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
NaN m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTC 212332
SVRSTC
MNC011-220030-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST CLOUD MINNESOTA
632 PM CDT SUN JUL 21 1991
 
THE NATIONAL WEATHER SERVICE IN ST CLOUD MINNESOTA   HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  730 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL MINNESOTA
 
   ...BIG STONE COUNTY
 
INCLUDING THE CITIES OF BEARDSLEY...CLINTON...ORTONVILLE AND
GRACEVILLE.
 
AT 625 PM RADAR INDICATED A SEVERE THUNDERSTORM APPROACHING
BIG STONE COUNTY FROM JUST EAST OF SISSETON SOUTH DAKATO.
THIS STORM WAS MOVING EAST AT 25 MPH AND HAS PRODUCED LARGE
HAIL.
 
 
 
 
A TORNADO WATCH IS ALSO IN EFFECT FOR THE WARNED AREA.  REMEMBER
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES
WITH LITTLE OR NO ADVANCE WARNING.  REMAIN CALM BUT BE ALERT TO
RAPIDLY CHANGING WEATHER CONDITIONS.
 
NNNN

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 7:04 PM CDTSevere Thunderstorm WarningMPXRedwood, Renville56 min
Jul 21, 6:30 PM CDTSevere Thunderstorm WarningMPXWabasha30 min
Jul 21, 6:37 PM CDTSevere Thunderstorm WarningMPXWinona38 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 1991Every severe thunderstorm warning 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.