Alert archive / Minnesota / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 43, NWS Twin Cities, MN

July 11, 1987Blue Earth County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 11, 1987, 7:42 AM CDT for Blue Earth County, Minnesota. It was in force for 48 min.

The area

The counties it named.

The facts

Issued
Jul 11, 1987, 7:42 AM CDT (12:42 UTC)
Expired
Jul 11, 1987, 8:30 AM CDT
In force
48 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Blue Earth 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 12:00Z, 0.7 hours before the alert went out and 98 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 1987-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2637 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 1987-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
2637 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
638 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KRST 111242
SVRRST
MNC013-111330-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ROCHESTER MN
742 AM CDT SAT JUL 11 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL  830 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTH CENTRAL MINNESOTA
          ...BLUE EARTH  ...INCLUDING THE CITY OF MANKATO...
 
AT 740 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM 25 MILES
SOUTHWEST OF MANKATO NEAR WILLOW CREEK. THIS SEVERE THUNDERSTORM WAS
MOVING TO THE NORTHEAST AT 40 MPH.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN ITS PATH YOU SHOULD
PREPARE FOR DAMAGING WIND IN EXCESS OF 55 MPH...LARGE HAIL...AND
DEADLY LIGHTNING.  PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT STAY AWAY FROM WINDOWS.

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 11, 5:35 AM CDT, 2 hours 7 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
535 AM CDT SAT JUL 11 1987

...SEVERE THUNDERSTORM WRNING FOR COTTONWOOD AND JACKSON COUNTIES OF
   SOUTHWEST MINNESOTA UNTIL 615 AM CDT THIS SATURDAY MORNING.....

AT 515 AM VERY HEAVY THUNDERSTORMS WERE APPROACHING THE MINNESOTA RIVER
BETWEEN GRANITE FALLS AND REDWOOD FALLS ALONG THE REDWOOD AND RENVILLE
COUNTY LINE IN SOUTHWEST MINNESOTA. THESE THUNDERSTORMS WERE PRODUCING
HEAVY RAINS..SMALL HAIL AND GUSTY WINDS TO 40 MPH. NO SEVERE WEATHER HAD
AS YET BEEN REPORTED WITH THESE THUNDERSTORMS BUT TO THE SOUTH HEAVIER
THUNDERSTORMS WERE MOVING OUT OF MURRAY AND NOBLES COUNTIES INTO
COTTONWOOD AND JACKSON COUNTIES OF SOUTHWEST MINNESOTA. THESE THUNDER-
STORMS WERE INDICATED AS SEVERE AND WARNINGS HAVE BEEN ISSUED FOR PORTIONS
OF THESE COUNTIES UNTIL 615 AM CDT THIS SATURDAY MORNING FOR LARGE HAIL
AND STRONG SURFACE WINDS.

ADDITIONAL SHOWERS AND THUNDERSTORMS WERE ALSO INDICATED OVER PORTIONS OF
CENTRAL MINNESOTA AND NORTHWEST WISCONSIN. SCATTERED LIGHT RAINSHOWRS WERE
LOCATED BETWEEN PRINCETON AND LAKE MILLE LACS IN CENTRAL MINNESOTA AND
SCATTERED HEAVY THUNDERSTORMS WERE LOCATED BET5WEEN SPOONER AND HAYWARD
IN NORTHWEST WISCONSIN.

MOVEMENT OF THESE SHOWER AND THUNDERSTORM AREAS WAS TO THE EAST NORTHEAST
AT 25 TO 30 MILES AN HOUR.
DOMBROWSKY

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 10, 10:00 PM CDTSevere Thunderstorm WarningMPXTodd60 min
Jul 10, 10:20 PM CDTTornado WarningMPXTodd25 min
Jul 11, 12:16 AM CDTSevere Thunderstorm WarningMPXCarver, Scott, Sibley44 min
Jul 11, 3:20 AM CDTSevere Thunderstorm WarningMPXLac qui Parle, Yellow Medicine60 min
Jul 11, 4:20 AM CDTSevere Thunderstorm WarningMPXYellow Medicine60 min
Jul 11, 5:50 AM CDTSevere Thunderstorm WarningMPXKandiyohi60 min
Jul 11, 6:15 AM CDTSevere Thunderstorm WarningMPXMeeker60 min
Jul 11, 6:45 AM CDTSevere Thunderstorm WarningMPXWright45 min
Jul 11, 7:11 AM CDTSevere Thunderstorm WarningMPXWatonwan49 min
Jul 11, 7:19 AM CDTSevere Thunderstorm WarningMPXHennepin, Sherburne21 min
Jul 11, 7:19 AM CDTSevere Thunderstorm WarningMPXAnoka, Isanti56 min
Jul 11, 7:52 AM CDTSevere Thunderstorm WarningMPXWashington28 min
Jul 11, 7:52 AM CDTSevere Thunderstorm WarningMPXChisago38 min
Jul 11, 4:47 PM CDTSevere Thunderstorm WarningMPXFaribault, Freeborn53 min
Jul 11, 4:47 PM CDTSevere Thunderstorm WarningMPXMartin53 min
Jul 11, 5:31 PM CDTSevere Thunderstorm WarningMPXDodge, Freeborn, Steele44 min
Jul 11, 5:48 PM CDTSevere Thunderstorm WarningMPXWabasha, Winona42 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 1987Every severe thunderstorm warning in 1987

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.