Alert archive / Iowa / Tornado Watches in 2004

Tornado Watch 78

April 17, 200425 counties in Iowa; 13 counties in Minnesota; 12 counties in Wisconsin

The Storm Prediction Center issued this tornado watch at Apr 17, 2004, 10:05 PM CDT for 25 counties in Iowa; 13 counties in Minnesota; 12 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 17, 2004, 10:05 PM CDT (03:05 UTC)
Expired
Apr 18, 2004, 3:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 50 counties

Allamakee County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clayton County, IA, Delaware County, IA, Dubuque County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Howard County, IA, Humboldt County, IA, Kossuth County, IA, Mitchell County, IA, Palo Alto County, IA, Pocahontas County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Houston County, MN, Martin County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN, Adams County, WI, Crawford County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Juneau County, WI, La Crosse County, WI, Lafayette County, WI, Monroe County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 127 km from the middle of the area, began a volume at 03:05 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

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

IssuedProductOfficeCountiesLasted
Apr 17, 10:08 PM CDTSevere Thunderstorm WarningARXMonroe52 min
Apr 17, 10:13 PM CDTSevere Thunderstorm WarningDMXWorth47 min
Apr 17, 10:19 PM CDTTornado WarningMPXFreeborn26 min
Apr 17, 10:21 PM CDTSevere Thunderstorm WarningARXCrawford, Vernon84 min
Apr 17, 10:25 PM CDTSevere Thunderstorm WarningDMXWinnebago65 min
Apr 17, 10:31 PM CDTSevere Thunderstorm WarningDMXKossuth44 min
Apr 17, 10:33 PM CDTTornado WarningDMXWorth27 min
Apr 17, 10:36 PM CDTTornado WarningARXChickasaw69 min
Apr 17, 10:44 PM CDTSevere Thunderstorm WarningARXJuneau76 min
Apr 17, 10:47 PM CDTTornado WarningARXFloyd73 min
Apr 17, 10:49 PM CDTTornado WarningARXMitchell56 min
Apr 17, 10:52 PM CDTSevere Thunderstorm WarningARXAllamakee23 min
Apr 17, 11:01 PM CDTTornado WarningDMXWorth29 min
Apr 17, 11:18 PM CDTSevere Thunderstorm WarningARXRichland87 min
Apr 17, 11:24 PM CDTSevere Thunderstorm WarningARXHoward96 min
Apr 17, 11:27 PM CDTSevere Thunderstorm WarningMPXSteele48 min
Apr 17, 11:37 PM CDTSevere Thunderstorm WarningARXWinneshiek83 min
Apr 17, 11:49 PM CDTSevere Thunderstorm WarningARXDodge56 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

Minneapolis, MN (KMPX), launched 00:00Z, 3.1 hours before the alert went out and 165 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, Minneapolis, MN at 00:00Z on 2004-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2004-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2026 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
489 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 180304
SEL8  
SPC WW 180305
IAZ000-MNZ000-WIZ000-180800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 78
NWS STORM PREDICTION CENTER NORMAN OK
1005 PM CDT SAT APR 17 2004

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

       NORTHERN IOWA
       SOUTHEAST MINNESOTA
       SOUTHWEST WISCONSIN

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 1005 PM
UNTIL 300 AM CDT.

TORNADOES...HAIL TO 2.5 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 EITHER SIDE
OF A LINE FROM 30 MILES SOUTHWEST OF FAIRMONT MINNESOTA TO 35
MILES EAST NORTHEAST OF LONEROCK WISCONSIN.

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 77. WATCH NUMBER 77 WILL NOT BE IN
EFFECT AFTER 1005 PM CDT. 

DISCUSSION...SUPERCELLS HAVE DEVELOPED ACROSS WRN PORTION OF WATCH
AND WITH LOW LEVEL JET INCREASING AND WARM UNSTABLE AIRMASS MOVING
NWD...POTENTIAL FOR ISOLATED TORNADOES EXISTS WITH THE SUPERCELLS...
COUPLED WITH LARGE HAIL AND DAMAGING WINDS. STORMS WILL CONTINUE
DEVELOPING EWD INTO SWRN WI

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 26035.


...HALES

441,0945 441,0893 423,0893 422,0945

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 17, 7:45 PM CDTSevere Thunderstorm WatchSPCAllamakee, Cerro Gordo, Chickasaw, Emmet, Floyd, Hancock and 7 more5 hr
Apr 17, 9:31 PM CDTMesoscale DiscussionSPCAllamakee, Cerro Gordo, Chickasaw, Emmet, Fayette, Floyd and 8 more119 min
Apr 17, 11:10 PM CDTMesoscale DiscussionSPCBuena Vista, Cherokee, Clay, Dickinson, Lyon, O'Brien and 3 more95 min
Apr 17, 11:35 PM CDTSevere Thunderstorm WatchSPCClay, Dickinson, Lyon, O'Brien, Osceola, Sioux5 hr
Apr 17, 11:50 PM CDTMesoscale DiscussionSPCCerro Gordo, Emmet, Hancock, Howard, Humboldt, Kossuth and 5 more85 min
Apr 18, 4:15 PM CDTMesoscale DiscussionSPCBuena Vista, Calhoun, Cerro Gordo, Cherokee, Clay, Dickinson and 20 more60 min
Apr 18, 4:40 PM CDTTornado WatchSPCAudubon, Buena Vista, Calhoun, Carroll, Cass, Cherokee and 29 more5 hr
Apr 18, 12:30 AM CDTSevere Thunderstorm WatchSPCAnoka, Carver, Chisago, Dakota, Goodhue, Hennepin and 11 more5 hr
Apr 18, 2:37 AM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Big Stone, Brown, Carlton and 40 more53 min
Apr 18, 4:43 AM CDTMesoscale DiscussionSPCAitkin, Benton, Carlton, Cass, Chisago, Crow Wing and 15 more32 min
Apr 18, 8:04 AM CDTMesoscale DiscussionSPCAitkin, Benton, Carlton, Cass, Crow Wing, Douglas and 6 more86 min
Apr 18, 12:39 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Big Stone, Carlton, Carver and 32 more2 hr
Apr 18, 1:40 PM CDTTornado WatchSPCAitkin, Anoka, Benton, Carlton, Carver, Chippewa and 32 more6 hr
Apr 18, 2:20 PM CDTSevere Thunderstorm WatchSPCLincoln, Lyon, Pipestone, Rock6 hr
Apr 18, 3:33 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 12 more117 min
Apr 18, 5:23 PM CDTMesoscale DiscussionSPCLincoln, Lyon, Pipestone, Rock2 hr
Apr 18, 6:35 PM CDTTornado WatchSPCBrown, Carver, Dakota, Goodhue, Hennepin, Le Sueur and 7 more5 hr
Apr 18, 1:49 AM CDTMesoscale DiscussionSPCCalumet, Columbia, Dane, Dodge, Fond du Lac, Green and 11 more56 min

Nearby

Tornado Watches in Iowa, 2004Tornado Watches in Minnesota, 2004Tornado Watches in Wisconsin, 2004Every tornado watch in 2004

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.