Alert archive / Nebraska / Tornado Watches in 2002

Tornado Watch 420

June 12, 200230 counties in Iowa; Atchison County, Missouri; 38 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Jun 12, 2002, 4:15 PM CDT for 30 counties in Iowa; Atchison County, Missouri; 38 counties in Nebraska. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jun 12, 2002, 4:15 PM CDT (21:15 UTC)
Expired
Jun 12, 2002, 9:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 69 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Decatur County, IA, Fremont County, IA, Greene County, IA, Guthrie County, IA, Harrison County, IA, Lucas County, IA, Madison County, IA, Marion County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Story County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Atchison County, MO, Adams County, NE, Boone County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Johnson County, NE, Kearney County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Valley County, NE, Washington County, NE, Webster County, NE, York County, NE

The radar

The Omaha radar (KOAX), 33 km from the middle of the area, began a volume at 21:15 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

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

IssuedProductOfficeCountiesLasted
Jun 12, 4:15 PM CDTSevere Thunderstorm WarningDMXClarke, Madison45 min
Jun 12, 4:29 PM CDTSevere Thunderstorm WarningDMXWarren31 min
Jun 12, 4:31 PM CDTSevere Thunderstorm WarningOAXCass, Lancaster, Saunders29 min
Jun 12, 4:34 PM CDTSevere Thunderstorm WarningGIDNance56 min
Jun 12, 4:38 PM CDTSevere Thunderstorm WarningOAXPlatte37 min
Jun 12, 4:53 PM CDTTornado WarningOAXButler, Platte37 min
Jun 12, 4:54 PM CDTSevere Thunderstorm WarningGIDMerrick66 min
Jun 12, 4:58 PM CDTSevere Thunderstorm WarningDMXPolk32 min
Jun 12, 5:01 PM CDTTornado WarningOAXCass29 min
Jun 12, 5:10 PM CDTSevere Thunderstorm WarningGIDPolk65 min
Jun 12, 5:13 PM CDTSevere Thunderstorm WarningDMXPolk, Warren47 min
Jun 12, 5:26 PM CDTTornado WarningGIDPolk49 min
Jun 12, 5:29 PM CDTSevere Thunderstorm WarningOAXButler31 min
Jun 12, 5:30 PM CDTSevere Thunderstorm WarningOAXCass30 min
Jun 12, 5:40 PM CDTSevere Thunderstorm WarningOAXFremont, Mills35 min
Jun 12, 5:46 PM CDTSevere Thunderstorm WarningGIDYork59 min
Jun 12, 5:50 PM CDTFlash Flood WarningDMXPolk6 hr
Jun 12, 5:50 PM CDTSevere Thunderstorm WarningDMXDallas40 min
Jun 12, 5:53 PM CDTSevere Thunderstorm WarningOAXDodge, Saunders37 min
Jun 12, 5:58 PM CDTSevere Thunderstorm WarningOAXSeward32 min
Jun 12, 6:00 PM CDTSevere Thunderstorm WarningOAXButler30 min
Jun 12, 6:14 PM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 12, 6:16 PM CDTSevere Thunderstorm WarningOAXFremont, Page29 min
Jun 12, 6:17 PM CDTTornado WarningOAXSeward28 min
Jun 12, 6:31 PM CDTSevere Thunderstorm WarningOAXLancaster, Saunders29 min
Jun 12, 6:35 PM CDTFlash Flood WarningDMXDallas3 hr
Jun 12, 6:45 PM CDTSevere Thunderstorm WarningOAXSaline, Seward30 min
Jun 12, 6:55 PM CDTSevere Thunderstorm WarningOAXPage35 min
Jun 12, 6:57 PM CDTSevere Thunderstorm WarningOAXBurt, Washington33 min
Jun 12, 7:43 PM CDTSevere Thunderstorm WarningOAXColfax, Dodge32 min
Jun 12, 7:56 PM CDTSevere Thunderstorm WarningGIDBuffalo64 min
Jun 12, 8:03 PM CDTSevere Thunderstorm WarningOAXSaunders27 min
Jun 12, 8:14 PM CDTTornado WarningGIDBuffalo61 min
Jun 12, 8:29 PM CDTSevere Thunderstorm WarningOAXSaunders31 min
Jun 12, 8:34 PM CDTSevere Thunderstorm WarningGIDAdams, Kearney56 min
Jun 12, 8:42 PM CDTTornado WarningGIDKearney48 min

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.3 hours before the alert went out and 32 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 12:00Z on 2002-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2034 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 12:00Z on 2002-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 square meters per square second.1939587897Sfc1 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
2034 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
700 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
61 m²/s²
Significant tornado parameter
-0.5
Supercell composite
-2.4

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 122100
SEL0  
SPC WW 122057
IAZ000-NEZ000-130200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 420
STORM PREDICTION CENTER NORMAN OK
357 PM CDT WED JUN 12 2002

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

   SOUTHERN IOWA                               
   SOUTHERN NEBRASKA                           

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 415 PM UNTIL
900 PM CDT.

TORNADOES...HAIL TO 3 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 NORTH AND
SOUTH OF A LINE FROM 15 MILES NORTHWEST OF KEARNEY NEBRASKA TO 30
MILES EAST OF DES MOINES IOWA.

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 SEVERE
THUNDERSTORM WATCH NUMBER 417.  WATCH NUMBER 417 WILL NOT BE IN
EFFECT AFTER 415 PM CDT.  CONTINUE...WW 418...WW 419...

DISCUSSION...STORMS WILL INTENSIFY RAPIDLY ACROSS WW AREA WHERE
AIRMASS IS VERY UNSTABLE.  WITH APPROACH OF MID/UPPER STRONGER
WINDS WITH NRN PLAINS UPPER LOW...SHEAR PROFILES FAVORABLE FOR
SUPERCELLS AND ISOLATED TORNADOES.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. 
MEAN STORM MOTION VECTOR 25030.


...HALES

414,0991 422,0930 403,0930 400,0991

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 12, 12:30 PM CDTSevere Thunderstorm WatchSPCCalhoun, Carroll, Crawford, Harrison, Ida, Mills and 5 more6 hr
Jun 11, 10:15 PM CDTSevere Thunderstorm WatchSPCBarton, Bates, Benton, Cass, Cedar, Dade and 10 more4 hr

Nearby

Tornado Watches in Nebraska, 2002Tornado Watches in Iowa, 2002Tornado Watches in Missouri, 2002Every tornado watch in 2002

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.