Alert archive / Nebraska / Tornado Watches in 2001

Tornado Watch 566

July 17, 200120 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Jul 17, 2001, 5:45 PM CDT for 20 counties in Nebraska. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jul 17, 2001, 5:45 PM CDT (22:45 UTC)
Expired: Jul 17, 2001, 11:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Colfax County, NE, Garfield County, NE, Greeley County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Rock County, NE, Stanton County, NE, Valley County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 158 km from the middle of the area, began a volume at 22:49 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

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

Issued	Product	Office	Counties	Lasted
Jul 17, 5:51 PM CDT	Tornado Warning	LBF	Rock	24 min
Jul 17, 6:08 PM CDT	Tornado Warning	LBF	Loup	52 min
Jul 17, 6:16 PM CDT	Severe Thunderstorm Warning	LBF	Rock	29 min
Jul 17, 6:34 PM CDT	Severe Thunderstorm Warning	LBF	Holt	56 min
Jul 17, 6:56 PM CDT	Severe Thunderstorm Warning	LBF	Garfield	64 min
Jul 17, 7:00 PM CDT	Severe Thunderstorm Warning	LBF	Loup	60 min
Jul 17, 7:18 PM CDT	Tornado Warning	LBF	Garfield, Loup	42 min
Jul 17, 7:19 PM CDT	Tornado Warning	LBF	Holt	56 min
Jul 17, 7:59 PM CDT	Tornado Warning	LBF	Garfield	61 min
Jul 17, 9:01 PM CDT	Severe Thunderstorm Warning	LBF	Garfield	59 min
Jul 17, 10:00 PM CDT	Severe Thunderstorm Warning	LBF	Garfield	30 min

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.8 hours before the alert went out and 203 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: 727 J/kg
Mixed-layer CIN: -340 J/kg
Mixed-layer LCL: 2212 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 187 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

655 
WWUS9 KMKC 172246
SEL6  

SEL6  
MKC WW 172240
NEZ000-180400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 566
STORM PREDICTION CENTER NORMAN OK
540 PM CDT TUE JUL 17 2001

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

   NORTHERN...CENTRAL AND EASTERN NEBRASKA                        
  
EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 545 PM UNTIL 1100
PM CDT.

TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 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 NORTH NORTHEAST OF AINSWORTH NEBRASKA TO 35
MILES WEST SOUTHWEST OF COLUMBUS 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 563...WW 564...WW 565...

DISCUSSION...SLOW MOVING/HIGH TOPPED SUPECELLS EXPECTED OVER PARTS
OF CENTRAL AND EASTERN NEBRASKA THIS EVENING...ALONG AXIS OF SBCAPE 
AOA 4000 J/KG.  BACKED LOW LEVEL FLOW INVOF STALLED OUTFLOW
BOUNDARY FROM EARLIER ELEVATED STORMS MAY ENHANCE LOW LEVEL SHEAR
TO SUPPORT THREAT FOR A FEW TORNADOES GIVEN HIGH SURFACE DEWPOINTS
/MID 70S/.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 650. 
MEAN STORM MOTION VECTOR 28015.

...CORFIDI

425,0981 411,0962 411,0993 425,1012

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 16, 10:00 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Boone, Burt, Butler, Colfax, Cuming and 14 more	3 hr

Nearby

Tornado Watches in Nebraska, 2001 Every tornado watch in 2001

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.