Alert archive / Minnesota / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 116, NWS Twin Cities, MN

July 21, 1991Winona County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 21, 1991, 6:37 PM CDT for Winona County, Minnesota. It was in force for 38 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
Jul 21, 1991, 6:37 PM CDT (23:37 UTC)
Expired
Jul 21, 1991, 7:15 PM CDT
In force
38 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Winona County, MN

What was reported inside it

TimeReportWhereRemark
Jul 21, 6:40 PM CDTHail 1.75Winona, MN

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 12:00Z, 11.6 hours before the alert went out and 174 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 1991-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 580 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 1991-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 square meters per square second.19395878Sfc1 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
580 J/kg
Mixed-layer CIN
-163 J/kg
Mixed-layer LCL
606 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-37 m²/s²
0-3 km storm-relative helicity
42 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 KRST 212338
SVRRST
MNC169-220015-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ROCHESTER MN
637 PM CDT SUN JUL 21 1991
 
THE NATIONAL WEATHER SERVICE IN ROCHESTER MN HAS ISSUED A
SEVERE THUNDERSTORM WARNING     EFFECTIVE UNTIL  700 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST MINNESOTA
 
   ...WINONA COUNTY
 
AT 635 ROCHERTER RADAR WAS INDICATING A SEVERE THUNDERSTORM IN THE
SOUTHWEST PORTION OF WINONA COUNTY. THE THUNDERSTORM APPEARED TO BE IN
THE VICINITY OF FREMONT WHICH IS 17 MILES SOUTHWEST OF WINONA.
 
THIS THUNDERSTORM WAS MOVING NORTH AT AROUND 15 MPH.
 
THIS WARNING INCLUDES THE CITIES OF UTICA...ALTURA...AND WINONA.
 
 
 
 
WHEN THUNDERSTORMS ARE OCCURRING..MOVE INSIDE A STRONG BUILDING
DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES OR ELECTRICAL
APPLIANCES UNLESS IN AN EMERGENCY. REMEMBER SEVERE THUNDERSTORMS
CAN AND OCCASIONALLY DO PRODUCE TORNADOS WITH LITTLE OR NO WARNING.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE. REMEMBER SEVERE THUNDERSTORMS
CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE ADVANCE WARNING

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, 6:32 PM CDTSevere Thunderstorm WarningMPXBig Stone58 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.