Alert archive / Nebraska / Tornado Watches in 2005

Tornado Watch 798

September 18, 20054 states

The Storm Prediction Center issued this tornado watch at Sep 18, 2005, 3:40 PM CDT for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 18, 2005, 3:40 PM CDT (20:40 UTC)
Expired
Sep 18, 2005, 11:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
All 52 counties

Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Page County, IA, Plymouth County, IA, Pottawattamie County, IA, Woodbury County, IA, Atchison County, MO, Adams County, NE, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Howard County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE, Union County, SD

The radar

The Omaha radar (KOAX), 136 km from the middle of the area, began a volume at 20:39 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

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

IssuedProductOfficeCountiesLasted
Sep 18, 4:15 PM CDTSevere Thunderstorm WarningLBFBrown, Rock45 min
Sep 18, 4:29 PM CDTSevere Thunderstorm WarningLBFHolt61 min
Sep 18, 4:56 PM CDTTornado WarningLBFRock34 min
Sep 18, 5:29 PM CDTSevere Thunderstorm WarningLBFHolt61 min
Sep 18, 6:27 PM CDTSevere Thunderstorm WarningOAXAntelope63 min
Sep 18, 6:29 PM CDTSevere Thunderstorm WarningLBFHolt61 min
Sep 18, 6:31 PM CDTTornado WarningLBFHolt29 min
Sep 18, 7:26 PM CDTSevere Thunderstorm WarningOAXAntelope41 min
Sep 18, 7:52 PM CDTSevere Thunderstorm WarningOAXMadison53 min
Sep 18, 8:22 PM CDTSevere Thunderstorm WarningOAXBoone15 min
Sep 18, 8:34 PM CDTSevere Thunderstorm WarningOAXPlatte56 min
Sep 18, 8:45 PM CDTSevere Thunderstorm WarningOAXMadison45 min
Sep 18, 8:48 PM CDTSevere Thunderstorm WarningOAXColfax42 min
Sep 18, 9:23 PM CDTSevere Thunderstorm WarningOAXButler37 min
Sep 18, 9:27 PM CDTSevere Thunderstorm WarningOAXDodge48 min
Sep 18, 9:30 PM CDTSevere Thunderstorm WarningOAXPlatte30 min
Sep 18, 9:42 PM CDTSevere Thunderstorm WarningOAXSaunders63 min
Sep 18, 10:03 PM CDTSevere Thunderstorm WarningFSDUnion21 min
Sep 18, 10:07 PM CDTSevere Thunderstorm WarningFSDPlymouth23 min
Sep 18, 10:15 PM CDTSevere Thunderstorm WarningOAXDodge30 min
Sep 18, 10:29 PM CDTSevere Thunderstorm WarningFSDPlymouth46 min
Sep 18, 10:29 PM CDTSevere Thunderstorm WarningOAXHarrison, Pottawattamie46 min
Sep 18, 10:38 PM CDTSevere Thunderstorm WarningOAXDouglas, Washington67 min
Sep 18, 10:42 PM CDTSevere Thunderstorm WarningOAXSaunders33 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.7 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-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2005-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1434 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 2005-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 square meters per square second.19395878Sfc1 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
1434 J/kg
Mixed-layer CIN
-240 J/kg
Mixed-layer LCL
812 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
3 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.

000 
WWUS20 KWNS 182044
SEL8  
SPC WW 182044
IAZ000-NEZ000-SDZ000-190400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 798
NWS STORM PREDICTION CENTER NORMAN OK
340 PM CDT SUN SEP 18 2005

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

       WESTERN IOWA
       CENTRAL AND EASTERN NEBRASKA
       SOUTHEASTERN SOUTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 340 PM UNTIL 1100
PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE MILES
EAST AND WEST OF A LINE FROM 65 MILES NORTH NORTHWEST OF NORFOLK
NEBRASKA TO 30 MILES SOUTH OF LINCOLN NEBRASKA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

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 797...

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP AND GRADUALLY
INCREASE IN INTENSITY FROM PARTS OF NEB THROUGH SERN SD AND IA THIS
AFTERNOON AND EVENING. VERTICAL SHEAR PROFILES SUPPORT SUPERCELLS
WITH VERY LARGE HAIL...DAMAGING WIND AND ISOLATED TORNADOES
POSSIBLE.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 26025.


...DIAL/HART

425,0960 402,0945 402,0983 425,0994

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 5:38 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 30 more97 min
Sep 18, 12:39 AM CDTMesoscale DiscussionSPCBarton, Bates, Cass, Cedar, Dade, Henry and 4 more66 min
Sep 18, 12:55 AM CDTSevere Thunderstorm WatchSPCBarton, Bates, Cass, Cedar, Dade, Henry and 5 more7 hr
Sep 18, 4:13 AM CDTMesoscale DiscussionSPCBarton, Bates, Benton, Camden, Cass, Cedar and 15 more92 min
Sep 18, 4:08 PM CDTMesoscale DiscussionSPCAndrew, Buchanan, Caldwell, Carroll, Cass, Chariton and 19 more2 hr
Sep 18, 1:50 PM CDTMesoscale DiscussionSPCAdams, Antelope, Blaine, Boone, Boyd, Brown and 37 more2 hr
Sep 18, 3:20 PM CDTSevere Thunderstorm WatchSPCBoyd, Keya Paha8 hr
Sep 18, 5:59 PM CDTMesoscale DiscussionSPCClark, Codington, Day, Faulk, Hand, Hughes and 7 more91 min

Nearby

Tornado Watches in Nebraska, 2005Tornado Watches in Iowa, 2005Tornado Watches in Missouri, 2005Every tornado watch in 2005

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.