Alert archive / Nebraska / Tornado Watches in 2001

Tornado Watch 126

April 11, 20014 states

The Storm Prediction Center issued this tornado watch at Apr 11, 2001, 2:00 AM CDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2001, 2:00 AM CDT (07:00 UTC)
Expired
Apr 11, 2001, 7:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 49 counties

Crawford County, IA, Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Pottawattamie County, IA, Shelby County, IA, Atchison County, KS, Brown County, KS, Clay County, KS, Dickinson County, KS, Douglas County, KS, Franklin County, KS, Geary County, KS, Jackson County, KS, Jefferson County, KS, Marshall County, KS, Morris County, KS, Nemaha County, KS, Osage County, KS, Pottawatomie County, KS, Riley County, KS, Shawnee County, KS, Wabaunsee County, KS, Washington County, KS, Atchison County, MO, Burt County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 70 km from the middle of the area, began a volume at 07:00 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.

IssuedProductOfficeCountiesLasted
Apr 11, 2:12 AM CDTSevere Thunderstorm WarningOAXGage63 min
Apr 11, 2:28 AM CDTSevere Thunderstorm WarningOAXBurt, Cuming, Dodge32 min
Apr 11, 2:34 AM CDTSevere Thunderstorm WarningOAXLancaster56 min
Apr 11, 2:38 AM CDTSevere Thunderstorm WarningOAXJohnson, Pawnee52 min
Apr 11, 2:51 AM CDTSevere Thunderstorm WarningOAXOtoe54 min
Apr 11, 2:58 AM CDTSevere Thunderstorm WarningOAXNemaha, Richardson62 min
Apr 11, 3:10 AM CDTSevere Thunderstorm WarningEAXAtchison50 min
Apr 11, 3:10 AM CDTSevere Thunderstorm WarningOAXCass50 min
Apr 11, 3:21 AM CDTSevere Thunderstorm WarningOAXFremont39 min
Apr 11, 3:34 AM CDTSevere Thunderstorm WarningOAXMills41 min
Apr 11, 3:57 AM CDTSevere Thunderstorm WarningOAXPottawattamie48 min

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 7.0 hours before the alert went out and 70 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, Omaha, NE at 00:00Z on 2001-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 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, Omaha, NE at 00:00Z on 2001-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 square meters per square second.1939587897117Sfc1 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
18 J/kg
Mixed-layer CIN
-145 J/kg
Mixed-layer LCL
493 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

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

000 
WWUS9 KMKC 110632
SEL6  

SEL6  
MKC WW 110625
IAZ000-KSZ000-MOZ000-NEZ000-111200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 126
STORM PREDICTION CENTER NORMAN OK
125 AM CDT WED APR 11 2001

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

   WEST CENTRAL AND SOUTHWEST IOWA                               
   NORTHEAST KANSAS                             
   EXTREME NORTHWEST MISSOURI                           
   EASTERN NEBRASKA                           

EFFECTIVE THIS WEDNESDAY MORNING FROM 200 AM UNTIL 700 AM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES EAST AND WEST
OF A LINE FROM 65 MILES NORTH NORTHWEST OF OMAHA NEBRASKA TO 45
MILES SOUTH SOUTHEAST OF MANHATTAN KANSAS.

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 123...WW 124...WW 125...

DISCUSSION...INTENSE BOW ECHO IS MOVING RAPIDLY ENEWD ACROSS NORTH
CENTRAL KANSAS TOWARD NORTHEAST KANSAS AND SOUTHEAST NEBRASKA...
WHILE OTHER CELLS CONTINUE TO DEVELOP AND INTENSIFY IN WARM
ADVECTION ZONE OVER EASTERN NEBRASKA TO THE NORTH OF THE WARM
FRONT.  WINDS ALOFT ARE EXPECTED TO CONTINUE STRENGTHENING THIS
MORNING AS UPPER TROUGH LIFTS NEWD TOWARD THE HIGH PLAINS...WITH
VERY STRONG LOW LEVEL SHEAR SPREADING ACROSS THE AREA.  SEVERE
STORMS WITH DAMAGING WINDS...HAIL AND ISOLATED TORNADOES WILL BE
POSSIBLE THROUGH THE EARLY MORNING HOURS. 


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. 
MEAN STORM MOTION VECTOR 23050.


...WEISS

;383,0972 420,0973 420,0951 383,0951;

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 4:00 AM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 21 more5 hr
Apr 11, 10:45 AM CDTTornado WatchSPCAdams, Cass, Crawford, Fremont, Harrison, Mills and 8 more5 hr
Apr 11, 12:00 PM CDTTornado WatchSPCAdair, Appanoose, Audubon, Benton, Black Hawk, Boone and 46 more5 hr
Apr 11, 4:00 PM CDTTornado WatchSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 40 more6 hr
Apr 10, 8:30 PM CDTSevere Thunderstorm WatchSPCCheyenne, Decatur, Finney, Gove, Grant, Gray and 18 more5 hr
Apr 10, 10:15 PM CDTSevere Thunderstorm WatchSPCEllis, Graham, Hodgeman, Jewell, Mitchell, Ness and 9 more6 hr
Apr 11, 12:00 AM CDTTornado WatchSPCBarber, Barton, Clark, Cloud, Comanche, Edwards and 20 more4 hr
Apr 11, 3:15 AM CDTTornado WatchSPCAllen, Anderson, Butler, Chase, Chautauqua, Coffey and 13 more5 hr
Apr 11, 9:30 AM CDTTornado WatchSPCDoniphan, Johnson, Leavenworth, Miami, Wyandotte6 hr
Apr 10, 7:00 PM CDTSevere Thunderstorm WatchSPCAudrain, Franklin, Jefferson, Lincoln, Montgomery, Saint Charles and 4 more5 hr
Apr 11, 6:15 AM CDTTornado WatchSPCBarry, McDonald, Newton, Stone6 hr
Apr 11, 10:00 AM CDTSevere Thunderstorm WatchSPCButler, Carter, Douglas, Howell, Oregon, Ozark and 2 more5 hr
Apr 11, 1:00 PM CDTTornado WatchSPCAdair, Audrain, Boone, Callaway, Clark, Cole and 20 more6 hr

Nearby

Tornado Watches in Nebraska, 2001Tornado Watches in Kansas, 2001Tornado Watches in Iowa, 2001Every 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.