Alert archive / Minnesota / Tornado Warnings in 1999

Tornado Warning 32, NWS Twin Cities, MN

August 12, 1999Le Sueur County, Minnesota

NWS Twin Cities, MN issued this tornado warning at Aug 12, 1999, 8:39 PM CDT for Le Sueur County, Minnesota. It was in force for 36 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
Aug 12, 1999, 8:39 PM CDT (01:39 UTC)
Expired
Aug 12, 1999, 9:15 PM CDT
In force
36 min
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Le Sueur County, MN

The radar

The Minneapolis radar (KMPX), 55 km from the middle of the area, began a volume at 01:40 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Aug 12, 9:13 PM CDTTornado F0Heidelberg, MNA few trees felled. Tornado continued into Rice County.

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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 1.7 hours before the alert went out and 54 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 1999-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 862 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 00:00Z on 1999-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 50 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
862 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
681 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
50 m²/s²
0-3 km storm-relative helicity
91 m²/s²
Significant tornado parameter
0.2
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KMPX 130139 RRA
TORMSP
MNC079-130215-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
839 PM CDT THU AUG 12 1999

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  LE SUEUR COUNTY IN SOUTH CENTRAL MINNESOTA

* UNTIL 915 PM CDT

* AT 839 PM CDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO 5 MILES WEST OF HEIDELBERG...OR ABOUT 17 MILES NORTHEAST OF
  ST PETER2...MOVING EAST AT 15 MPH.

* SOME LOCATIONS IN THE PATH OF THIS TORNADO INCLUDE...
  MONTGOMERY
  HEIDELBERG

GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR!

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 8:59 PM CDTTornado WarningMPXRice, Scott31 min
Aug 12, 9:32 PM CDTTornado WarningMPXDakota, Scott28 min

Nearby

Tornado Warnings in Minnesota, 1999Every tornado warning in 1999Tornadoes in 1999

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; radar from the NEXRAD Level II archive.