Alert archive / Minnesota / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 60, NWS Twin Cities, MN

July 20, 1987Dakota County, Scott County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 20, 1987, 6:55 PM CDT for Dakota County, Scott County, Minnesota. It was in force for 50 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 20, 1987, 6:55 PM CDT (23:55 UTC)
Expired
Jul 20, 1987, 7:45 PM CDT
In force
50 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

Counties Dakota County, MN, Scott County, MN

The radar

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

What was reported inside it

TimeReportWhereRemark
Jul 20, 7:15 PM CDTHail 1.75Dakota, 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, 11.9 hours before the alert went out and 32 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 1987-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4599 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 1987-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 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
4599 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
604 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
192 m²/s²
Significant tornado parameter
0.0
Supercell composite
15.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KMSP 202355
SVRMSP
MNC139-037-210045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MINNEAPOLIS MN
655 PM CDT MON JUL 20 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 745 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES OF

SOUTHEAST MINNESOTA...
 EASTERN SCOTT AND DAKOTA


AT 645 PM CDT..A SEVERE THUNDERSTORM PRODUCED GOLFBALL SIZE HAIL
IN THE BURNSVILLE AREA OF NORTHWEST DAKOTA COUNTY.

THIS THUNDERSTORM WAS MOVING EAST AT 20 MILES AN HOUR AND WILL BE
AFFECTING AREAS NEAR THE TOWNS OF PRIOR LAKE..APPLE VALLEY..
EAGAN..LAKEVILLE AND HASTINGS.

REMEMBER SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60
MPH..DESTRUCTIVE HAIL..DEADLY LIGHTNING AND VERY HEAVY RAIN. 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, Jul 20, 1:02 PM CDT, 5 hours 53 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
 100 PM CDT MON JUL 20 1987

 ...VERY STRONG THUNDERSTORM DEVELOPING OVER WEST CENTRAL WISCONSIN...

AT 1255 PM CDT...A LINE OF STRONG THUNDERSTORMS EXTENDED WEST FROM BARRON
IN BARRON COUNTY TO TO NEAR BALDWIN IN ST CROIX COUNTY... WHICH IS 35 TO
40 MILES NORTHWEST OF EAU CLAIR.
THESE THUNDERSTORMS WERE MOVING EAST SOUTHEAST AT 35 MILES AN HOUR.
SOME CITIES IN THE PATH OF THESE THUNDERSTORMS ARE...WHEELER AND MENOMINEE
IN DUNN COUNTY..CHETAC IN BARRON COUNTY AND ELMWOOD IN PIERCE COUNTY.

HAIL AND WINDS IN THE 50 MPH RANGE ARE POSSIBLE FROM THESE THUNDERSTORMS.

IF THESE THUNDERSTORMS MAINTAIN THEIR PRESENT STRENGTH AND MOVEMENT THEY
WILL BE APPROACHING THE EAU CLAIRE AREA AROUND 2PM.

IF THREATENING WEATHER APPROACHES BE PREPARED TO MOVE TO A PLACE OF SAFETY.
PAULSON
Local storm report, Jul 20, 1:23 PM CDT, 5 hours 32 minutes before
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
115 PM CDT MON JUL 20 198
      ...ATTN SELS A MSP...

       ...NOTE ALL REPORTS ARE FOR WISCONSIN COUNTIES.

1015 AM CDT  LARGE TREES DOWN BETWEEN RICE LAKE AND CAMERON IN BARRON
             COUNTY.   FROM BARRON COUNTY SHERIFFS OFFICE.

1027 AM    LARGE TREE DAMGE NR CHRISTIE MOUNTAIN...ABOUT 10 TO 15 MILES
           NORTHWEST OF LADYSMITH IN RUSK COUNTY.  REPORT OF CONFIRMED
           TORNADO.   FROM RUSK COUNTY SHERIFFS OFFICE.

1105 AM    LARGE TREES DOWN 5 MILES EAST OF AUBURN IN NORTHWEST
           CHIPPEWA COUNTY. FROM CHIPPEWA COUNTY SHERIFFS OFFICE.

953 AM     LARGE TREES DOWN AND DAMAGE TO A BARN AND SHED ABOUT 3 MILES
           EAST OF RICE LAKE.  FROM BARRON COUNTY SHERIFFS OFFICE.

1002 AM    LARGE TREES DOWN IN BARRON IN BARRON COUNTY FROM BARRON
      COUNTY SHERIFFS OFFICE.

1050 AM  (APPROXIMATED TIME)   LARGE TREES DOWN IN CHETEK IN BARRON
       COUNTY FROM BARRON COUNTY SHERIFFS OFFICE.

BETWEEN 11 AM AND 1130 AM....4 INCH DIAMETER TREES AND LARGE BRANCHES
        DOWN NEAR HOLCOMBE IN NORTHEAST CHIPPEWA COUNTY.  FROM NORTHERN
        STATES POWER COMPANY.

PAULSON
Special weather statement, Jul 20, 2:16 PM CDT, 4 hours 39 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
215 PM CDT MON JUL 20 1987

...SEVERE THUNDERSTORM WATCH NUMBER 404 CANCELED FOR EAST CENTRAL
   MINNESOTA...

THE NATIONAL WEATHER SERVICE HAS CANCELED THE SEVERE THUNDERSTORM WATCH
ISSUED EARLIER FOR EAST CENTRAL MINNESOTA WHICH INCLUDED THE TWIN CITIES
METRO AREA.

THE LINE OF THUNDERSTORMS HAD MOVED OUT OF MINNESOTA AND INTO WEST
WISCONSIN.

WITH A FRONTAL BOUNDARY STILL PRESENT OVER SOUTHERN MINNESOTA JUST
SOUTH OF THE TWIN CITIES...THUNDERSTORMS COULD REDEVELOP LATER THIS
AFTERNOON.

PERSONS SHOULD REMAIN ALERT TO LATER FORECASTS AND STATEMENTS FROM
THE NATIONAL WEATHER SERVICE DURING THE AFTERNOON.
JHM
Special weather statement, Jul 20, 2:53 PM CDT, 4 hours 2 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
250 PM CDT MON JUL 20 1987

AT 235 PM CDT...INTENSE THUNDERSTORMS CONTINUED OVER WEST CENTRAL
WISCONSIN FROM 35 MILES SOUTHEAST OF EAU CLAIRE NEAR FAIRCHILD TO 40
MILES SOUTHWEST OF EAU CLAIRE NEAR MONDOVI.

VERY HEAVY RAINS..STRONG GUSTY WINDS AND DANGEROUS LIGHTNING CAN BE
 EXPECTED WITH THESE STORMS AS THEY MOVE SOUTH AT 45 MILES AN HOUR.

THE STORMS SHOULD BE LOCATED ALONG A LINE FROM NEAR BLACK RIVER FALLS TO
25 MILES NORTH OF LA CROSSE BY 315 PM CDT.

THESE STORMS WERE PART OF AN AREA OF SHOWERS AND THUNDERSTORMS THAT
EXTENDED FROM 25 MILES EAST OF HAYWARD TO 25 MILES WEST OF WAUSAU TO#
SOUTH OF EAU CLAIRE.
STANDFIELD
JHM
Special weather statement, Jul 20, 3:47 PM CDT, 3 hours 8 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
345 PM CDT MON JUL 20 1987

....SEVERE THUNDERSTORM WATCH UNTIL 9 PM CDT FOR PARTS OF WEST CENTRAL
WISCONSIN....

AT 330 PM CDT...STRONG THUNDERSTORMS CONTINUED OVER WEST CENTRAL WISCONSIN
35 MILES NORTHEAST OF LA CROSSE JUST NORTH AND WEST OF BLACK RIVER FALLS.

THE STORMS WERE MOVING SOUTH AT 40 MILES AN HOUR AND SHOULD BE LOCATED
JUST NORTHEAST OF LA CROSSE TO NORTH OF TOMAH BY 415 PM CDT.

VERY HEAVY RAINS...STRONG GUSTY WINDS AND DANGEROUS LIGHTNING CAN BE
 EXPECTED WITH THE STORMS.

ELSEWHERE..SHOWERS AND THUNDERSTORMS HAD DEVELOPED OVER WEST CENTRAL
MINNESOTA FROM THE MINNESOTA/SOUTHI DAKOTA BORDER NEAR BIG STONE LAKE
TO WEST OF ALEXANDRIA TO 35 MILES SOUTH OF DETROIT LAKES.
MOVEMENT WAS NORTHEAST AT 45 MILES AN HOUR. STANDFIELD
Special weather statement, Jul 20, 6:21 PM CDT, 34 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MINNEAPOLIS/ST PAUL MN
615 PM CDT MON JUL 20 1987

    ..THUNDERSTORMS TO AFFECT THE LAKE MINNETONKA AREA..

A STRONG THUNDERSTORM HAS BEEN DEVELOPING RAPIDLY OVER WESTERN HENNEPIN
COUNTY IN THE MOUND AND INDEPENDENCE AREA. THIS THUNDERSTORM WAS SLOWLY
MOVING TO THE EAST SOUTHEAST AND IT WILL MOVE ACROSS PARTS OF LAKE
MINNETONKA THROUGH 700 PM.

SOME LIGHTNING..GUSTY WINDS AND HEAVY RAINS ARE POSSIBLE WITH THIS STORM.

PERSONS BOATING OR FISHING ON LAKE MINNETONKA SHOULD MAKE PLANS NOW TO
HEAD FOR SAFE HARBOR UNTIL THE THUNDERSTORMS PASS BY THE LAKE.

AT 615 PM CDT..OTHER THUNDERSTORMS WERE FORMING OVER SCOTT..WESTERN ANOKA
AND WRIGHT COUNTIES OF THE WESTERN METROPOLITAN AREA.

THEY WERE MOVING EAST AT ABOUT 20 MILES AN HOUR.
SWANBERG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 9:25 AM CDTSevere Thunderstorm WarningMPXTodd55 min
Jul 20, 6:36 PM CDTSevere Thunderstorm WarningMPXAnoka, Hennepin, Wright54 min
Jul 20, 6:41 PM CDTSevere Thunderstorm WarningMPXSherburne49 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.