Alert archive / Minnesota / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 174, NWS Twin Cities, MN

September 21, 1986Redwood County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Sep 21, 1986, 12:45 AM CDT for Redwood County, Minnesota. It was in force for 55 min.

The area

The counties it named.

The facts

Issued
Sep 21, 1986, 12:45 AM CDT (05:45 UTC)
Expired
Sep 21, 1986, 1:40 AM CDT
In force
55 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Redwood County, MN

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Minneapolis, MN (KSTC), launched 00:00Z, 5.8 hours before the alert went out and 140 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 1986-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 1986-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 square meters per square second.193958Sfc1 km3 km6 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
531 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
228 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KMSP 210545
SVRMSP
MNC127-210640-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MINNEAPOLIS MN
1245 AM CDT SUN SEP 21 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 140 AM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

SOUTHWEST MINNESOTA...REDWOOD

AT 1240 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM WITH HAIL
INDICATED IN THE SOUTHWEST CORNER OF REDWOOD COUNTY..ABOUT 25
MILES SOUTHWEST OF REDWOOD FALLS.  THE SEVERE THUNDERSTORM WAS
MOVING TO THE NORTHEAST AT 25 MPH.

REMEMBER SEVERE THUNDERSTORMS PRODUCE STRONG DAMAGING WINDS..LARGE
HAIL AND FREQUENT LIGHTNING STRIKES. ALSO SEVERE THUNDERSTORMS CAN
AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE OR NO ADVANCE
WARNING..SO BE ON THE LOOKOUT AND BE PREPARED TO MOVE TO A PLACE OF
SAFETY IF ONE IS SPOTTED.

BRANCH

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, Sep 20, 8:49 PM CDT, 3 hours 56 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
845 PM CDT SAT SEP 20 1986

AT 830 PM SHOWERS AND ISOLATED THUNDERSTORMS WERE CONTINUING TO INCREASE
IN AREA OVER CENTRAL..SOUTH CENTRAL AND SOUTHEAST MINNESOTA INTO SOUTH-
WEST WISCONSIN. A DECREASE IN OVERALL INTENSITY WAS ALSO NOTED SINCE
730 PM.

THE AREA EXTENDED ALONG AND SOUTH OF A LINE FROM NEAR JACKSON MINNESOTA
TO ST PETER EAST TO ABOUT 35 MILES SOUTHEAST OF THE TWIN CITIES NEAR
ZUMBROTA AND ON INTO SOUTHWEST WISCONSIN EAST OF LA CROSSE NEAR TOMAH.

INTENSE THUNDERSTORMS WITH VERY HEAVY RAINS CONTINUED FROM JUST SOUTH
OF ROCHESTER SOUTH TO THE MINNESOTA IOWA BORDER NEAR HARMONY. THESE
INTENSE THUNDERSTORMS HAVE BEEN PRODUCING VERY HEAVY RAINS WITH SOME
REPORTS OF 3 INCHES OR MORE THIS AFTERNOON AND EVENING. OTHER SHOWERS
HAVE BEGUN FORMING OVER SOUTH CENTRAL MINNESOTA JUST WEST OF THE AREA
HAVING RECIEVED THE HEAVY RAINS...ANDR THIS CAN ONLY AGGRAVATE THE
SITUATION IN THOSE AREAS. THEREFORE..PERSONS IN SOUTH CENTRAL AND
SOUTHEAST MINNESOTA SHOULD BE ALERT FOR POSSIBLE FLOODING OF DITCHES
AND UNDERPASSES AS WELL AS SOME SMALL STREAMS.
LRS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 4:17 AM CDTFlash Flood WarningMPXOlmsted3 hr

Nearby

Severe Thunderstorm Warnings in Minnesota, 1986Every severe thunderstorm warning in 1986

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.