Alert archive / Minnesota / Tornado Warnings in 1987

Tornado Warning 17, NWS Twin Cities, MN

July 20, 1987Dakota County, Minnesota

NWS Twin Cities, MN issued this tornado warning at Jul 20, 1987, 7:06 PM CDT for Dakota County, Minnesota. It was in force for 24 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, 7:06 PM CDT (00:06 UTC)
Expired
Jul 20, 1987, 7:30 PM CDT
In force
24 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Dakota 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 00:00Z, 0.1 hours before the alert went out and 47 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 1987-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3871 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 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 1987-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
3871 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
860 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.9
Supercell composite
4.4

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KMSP 210006
TORMSP
MNC037-210030-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING
NATIONAL WEATHER SERVICE MINNEAPOLIS MN
706 PM CDT MON JUL 20 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 730 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST MINNESOTA...NORTHERN DAKOTA


AT..RADAR WAS INDICATING A POSSIBLE TORNADO IN THE BURNSVILLE
AREA OF NORTHERN DAKOTA COUNTY. REPORTS OF ROTATING FUNNEL CLOUDS
HAVE BEEN RECIEVED IN THIS SAME AREA.

THE THUNDERSTORM PRODUCING THE POSSIBLE TORNADO WAS MOVING EAST
AT 20 MILES AN HOUR AND WILL BE AFFECTING THE CITIES OF APPLE
VALLEY..ROSEMOUNT..EAGAN AND INVER GROVE HEIGHTS.

THIS IS A DANGEROUS STORM SITUATION.  ACT QUICKLY.  IF YOU ARE IN
THE PATH OF A TORNADO MOVE TO A SHELTER BELOW GROUND IF AVAILABLE.
OTHERWISE..GO TO A SMALL INTERIOR ROOM ON THE LOWEST FLOOR
POSSIBLE.  AVOID WINDOWS.  ABANDON CARS AND MOBILE HOMES FOR A
RE6INFORCED BUILDING OR GET INTO A DITCH OR CULVERT.

BRANCH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 7:13 PM CDTTornado WarningMPXAnoka, Hennepin, Ramsey27 min
Jul 20, 7:14 PM CDTSevere Thunderstorm WarningMPXMeeker61 min
Jul 20, 8:00 PM CDTSevere Thunderstorm WarningMPXLac qui Parle60 min
Jul 20, 8:09 PM CDTSevere Thunderstorm WarningMPXRamsey, Washington51 min
Jul 20, 9:34 PM CDTSevere Thunderstorm WarningMPXHennepin, Scott56 min
Jul 20, 9:45 PM CDTSevere Thunderstorm WarningMPXKandiyohi, Meeker60 min
Jul 20, 10:36 PM CDTSevere Thunderstorm WarningMPXCarver, Hennepin54 min

Nearby

Tornado Warnings in Minnesota, 1987Every tornado warning in 1987Tornadoes 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.