Alert archive / Nebraska / Tornado Watches in 1997

Tornado Watch 749

October 11, 199717 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Oct 11, 1997, 5:30 PM MDT for 17 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Oct 11, 1997, 5:30 PM MDT (23:30 UTC)
Expired: Oct 11, 1997, 11:00 PM MDT
In force: 6 hr
Issued by: the Storm Prediction Center

Counties Arthur County, NE, Banner County, NE, Box Butte County, NE, Cherry County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, Kimball County, NE, McPherson County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE

The radar

The North Platte radar (KLNX), 181 km from the middle of the area, began a volume at 23:29 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Oct 11, 6:10 PM MDT	Severe Thunderstorm Warning	CYS	Cheyenne	45 min
Oct 11, 7:05 PM MDT	Severe Thunderstorm Warning	CYS	Cheyenne	40 min
Oct 11, 7:30 PM MDT	Severe Thunderstorm Warning	LBF	Deuel, Garden	60 min
Oct 11, 7:46 PM MDT	Severe Thunderstorm Warning	LBF	Arthur, Garden, Grant	64 min
Oct 11, 8:02 PM MDT	Severe Thunderstorm Warning	LBF	Deuel, Garden, Keith	63 min
Oct 11, 8:50 PM MDT	Severe Thunderstorm Warning	LBF	Arthur, Grant	60 min
Oct 11, 9:52 PM MDT	Severe Thunderstorm Warning	LBF	Arthur	48 min
Oct 11, 10:50 PM MDT	Flash Flood Warning	LBF	Deuel	3 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.5 hours before the alert went out and 191 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: 175 J/kg
Mixed-layer CIN: -304 J/kg
Mixed-layer LCL: 903 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 237 m²/s²
0-3 km storm-relative helicity: 206 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

130 
WWUS9 KMKC 112301
SEL9  
MKC WW 112301
NEZ000-120500-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 749
STORM PREDICTION CENTER NORMAN OK
501 PM MDT SAT OCT 11 1997

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

   WESTERN NEBRASKA                           

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 530 PM UNTIL
1100 PM MDT.

TORNADOES...HAIL TO 1 3/4 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 85 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS ALONG AND 80 STATUTE MILES EAST AND WEST
OF A LINE FROM 30 MILES EAST SOUTHEAST OF SIDNEY NEBRASKA TO 35
MILES EAST NORTHEAST OF CHADRON NEBRASKA.

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...  CONTINUE...WW 746...WW 747...WW 748...

DISCUSSION...THUNDERSTORMS AND POSSIBLE SUPERCELLS EXPECTED TO
SPREAD NORTHEASTWARD FROM COLORADO ALONG CONVERGENCE LINE IN
WESTERN PART OF WATCH.  VERY STRONG UNIDIRECTIONAL SHEAR SUGGESTS
POSSIBILITY OF BOWS...WITH GREATEST RISK OF TORNADOES IN VICINITY
OF BOW HEADS.   

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 3/4 INCHES.  EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 75 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
480.  MEAN STORM MOTION VECTOR 20040.


...CORFIDI

405,1035 425,1040 425,1005 405,1005

Nearby

Tornado Watches in Nebraska, 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.