Alert archive / South Dakota / Tornado Watches in 1997

Tornado Watch 751

October 11, 1997Traverse County, Minnesota; 36 counties in South Dakota

The Storm Prediction Center issued this tornado watch at Oct 11, 1997, 9:45 PM CDT for Traverse County, Minnesota; 36 counties in South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Oct 11, 1997, 9:45 PM CDT (02:45 UTC)
Expired: Oct 12, 1997, 4:00 AM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 37 counties

Traverse County, MN, Aurora County, SD, Beadle County, SD, Bennett County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Campbell County, SD, Charles Mix County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Douglas County, SD, Edmunds County, SD, Faulk County, SD, Gregory County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jerauld County, SD, Jones County, SD, Kingsbury County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Mellette County, SD, Potter County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 178 km from the middle of the area, began a volume at 02:56 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.

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 2.8 hours before the alert went out and 136 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1775 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 1371 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 155 m²/s²
0-3 km storm-relative helicity: 181 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 8.6

Open this sounding in Storm Lab

The text

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

152 
WWUS9 KMKC 120206
SEL1  
MKC WW 120206
SDZ000-MNZ000-120900-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 751
STORM PREDICTION CENTER NORMAN OK
906 PM CDT SAT OCT 11 1997

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   CENTRAL AND EASTERN SOUTH DAKOTA                       
   A SMALL PART OF WEST CENTRAL MINNESOTA                         

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 945 PM UNTIL
400 AM CDT.

TORNADOES...HAIL TO 1 3/4 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS ALONG AND 90 STATUTE MILES EAST AND WEST
OF A LINE FROM 70 MILES SOUTHWEST OF CHAMBERLAIN SOUTH DAKOTA TO 35
MILES NORTH NORTHEAST OF ABERDEEN SOUTH DAKOTA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO WATCH
NUMBER 746.  WATCH NUMBER 746 WILL NOT BE IN EFFECT AFTER 945 PM
CDT.  CONTINUE...WW 747...WW 748...WW 749...WW 750...

DISCUSSION...STRONG LOW LEVEL UNIDIRECTIONAL SHEAR AND AMPLE
BOUNDARY LAYER MOISTURE INFLOW SUGGEST THAT THREAT FOR BOW ECHOES
WITH DAMAGING WINDS AND ISOLATED BOW HEAD TORNADOES WILL CONTINUE 
INTO THE NIGHT AS COLD FRONT MOVES EAST ACROSS WATCH AREA. 
 
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 3/4 INCHES.  EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
480.  MEAN STORM MOTION VECTOR 21040.

...CORFIDI

430,1020 455,1000 455,0961 430,0983

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 11, 8:45 PM CDT	Tornado Watch	SPC	Clay, Kittson, Marshall, Norman, Pennington, Polk and 3 more	6 hr

Nearby

Tornado Watches in South Dakota, 1997 Tornado Watches in Minnesota, 1997 Every tornado watch in 1997

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; radar from the NEXRAD Level II archive.