Alert archive / Iowa / Tornado Watches in 2004
Tornado Watch 85
The Storm Prediction Center issued this tornado watch at Apr 18, 2004, 4:40 PM CDT for 4 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 18, 2004, 4:40 PM CDT (21:40 UTC)
- Expired
- Apr 18, 2004, 10:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
All 83 counties
Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Fremont County, IA, Greene County, IA, Hancock County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Murray County, MN, Nobles County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Adams County, NE, Burt County, NE, Butler County, NE, Cass 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, Gage County, NE, Hamilton County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Merrick County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thayer County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, York County, NE, Union County, SD
The radar
The Omaha radar (KOAX), 44 km from the middle of the area, began a volume at 21:43 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
56 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 18, 4:45 PM CDT | Severe Thunderstorm Warning | FSD | Sioux | 30 min |
| Apr 18, 4:56 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 49 min |
| Apr 18, 5:11 PM CDT | Severe Thunderstorm Warning | FSD | Murray, Nobles, Rock | 49 min |
| Apr 18, 5:13 PM CDT | Tornado Warning | FSD | Union | 47 min |
| Apr 18, 5:16 PM CDT | Tornado Warning | FSD | Nobles | 44 min |
| Apr 18, 5:18 PM CDT | Severe Thunderstorm Warning | FSD | Sioux | 42 min |
| Apr 18, 5:44 PM CDT | Severe Thunderstorm Warning | FSD | Union | 46 min |
| Apr 18, 5:47 PM CDT | Severe Thunderstorm Warning | FSD | Cottonwood | 28 min |
| Apr 18, 5:47 PM CDT | Severe Thunderstorm Warning | FSD | Dixon | 43 min |
| Apr 18, 5:47 PM CDT | Flash Flood Warning | FSD | Union | 58 min |
| Apr 18, 5:50 PM CDT | Tornado Warning | OAX | Wayne | 30 min |
| Apr 18, 5:51 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 24 min |
| Apr 18, 5:55 PM CDT | Severe Thunderstorm Warning | FSD | Nobles | 35 min |
| Apr 18, 5:59 PM CDT | Severe Thunderstorm Warning | FSD | Sioux | 61 min |
| Apr 18, 6:17 PM CDT | Severe Thunderstorm Warning | FSD | Cottonwood, Murray | 43 min |
| Apr 18, 6:19 PM CDT | Severe Thunderstorm Warning | FSD | Osceola | 56 min |
| Apr 18, 6:20 PM CDT | Tornado Warning | OAX | Wayne | 25 min |
| Apr 18, 6:24 PM CDT | Severe Thunderstorm Warning | FSD | Jackson | 36 min |
| Apr 18, 6:26 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 64 min |
| Apr 18, 6:29 PM CDT | Severe Thunderstorm Warning | FSD | Dixon | 46 min |
| Apr 18, 6:29 PM CDT | Severe Thunderstorm Warning | OAX | Madison, Platte, Stanton | 46 min |
| Apr 18, 6:35 PM CDT | Tornado Warning | FSD | Cottonwood | 25 min |
| Apr 18, 6:38 PM CDT | Severe Thunderstorm Warning | FSD | O'Brien | 67 min |
| Apr 18, 6:46 PM CDT | Severe Thunderstorm Warning | OAX | Wayne | 44 min |
| Apr 18, 6:49 PM CDT | Severe Thunderstorm Warning | FSD | Dakota | 41 min |
| Apr 18, 6:52 PM CDT | Severe Thunderstorm Warning | MPX | Martin, Watonwan | 38 min |
| Apr 18, 6:55 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 50 min |
| Apr 18, 6:59 PM CDT | Severe Thunderstorm Warning | FSD | Dickinson | 46 min |
| Apr 18, 7:02 PM CDT | Severe Thunderstorm Warning | OAX | Cuming, Thurston | 58 min |
| Apr 18, 7:12 PM CDT | Severe Thunderstorm Warning | FSD | Clay | 63 min |
| Apr 18, 7:13 PM CDT | Severe Thunderstorm Warning | OAX | Madison, Platte, Stanton | 47 min |
| Apr 18, 7:21 PM CDT | Severe Thunderstorm Warning | FSD | Jackson | 24 min |
| Apr 18, 7:22 PM CDT | Severe Thunderstorm Warning | MPX | Blue Earth, Faribault | 53 min |
| Apr 18, 7:24 PM CDT | Severe Thunderstorm Warning | OAX | Lancaster, Saunders | 51 min |
| Apr 18, 7:29 PM CDT | Severe Thunderstorm Warning | MPX | Martin | 61 min |
| Apr 18, 7:36 PM CDT | Severe Thunderstorm Warning | OAX | Douglas | 24 min |
| Apr 18, 7:54 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 36 min |
| Apr 18, 7:56 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 34 min |
| Apr 18, 7:56 PM CDT | Severe Thunderstorm Warning | OAX | Cuming, Thurston | 49 min |
| Apr 18, 7:57 PM CDT | Severe Thunderstorm Warning | OAX | Harrison | 33 min |
| Apr 18, 8:00 PM CDT | Severe Thunderstorm Warning | OAX | Douglas | 15 min |
| Apr 18, 8:01 PM CDT | Tornado Warning | FSD | Woodbury | 29 min |
| Apr 18, 8:17 PM CDT | Severe Thunderstorm Warning | MPX | Faribault, Freeborn, Steele, Waseca | 58 min |
| Apr 18, 8:19 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 26 min |
| Apr 18, 8:22 PM CDT | Severe Thunderstorm Warning | OAX | Burt | 38 min |
| Apr 18, 8:25 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee | 50 min |
| Apr 18, 8:30 PM CDT | Severe Thunderstorm Warning | OAX | Monona | 45 min |
| Apr 18, 8:34 PM CDT | Severe Thunderstorm Warning | OAX | Colfax | 41 min |
| Apr 18, 8:36 PM CDT | Severe Thunderstorm Warning | DMX | Emmet, Kossuth | 24 min |
| Apr 18, 8:48 PM CDT | Tornado Warning | OAX | Butler | 27 min |
| Apr 18, 8:52 PM CDT | Severe Thunderstorm Warning | OAX | Dodge | 53 min |
| Apr 18, 8:59 PM CDT | Severe Thunderstorm Warning | OAX | Seward | 46 min |
| Apr 18, 9:00 PM CDT | Severe Thunderstorm Warning | DMX | Palo Alto, Pocahontas | 15 min |
| Apr 18, 9:09 PM CDT | Severe Thunderstorm Warning | OAX | Jefferson | 51 min |
| Apr 18, 9:20 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Pocahontas | 25 min |
| Apr 18, 9:34 PM CDT | Severe Thunderstorm Warning | DMX | Hancock, Wright | 26 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, 9.7 hours before the alert went out and 44 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.
- Mixed-layer CAPE
- 256 J/kg
- Mixed-layer CIN
- -464 J/kg
- Mixed-layer LCL
- 995 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 365 m²/s²
- 0-3 km storm-relative helicity
- 406 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 182142
SEL5
SPC WW 182140
IAZ000-MNZ000-NEZ000-190300-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 85
NWS STORM PREDICTION CENTER NORMAN OK
440 PM CDT SUN APR 18 2004
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
WESTERN IOWA
SOUTHERN MINNESOTA
EASTERN NEBRASKA
EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 440 PM UNTIL 1000
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 80 STATUTE MILES EAST AND WEST
OF A LINE FROM 35 MILES NORTH NORTHEAST OF FAIRMONT MINNESOTA TO
35 MILES WEST SOUTHWEST OF BEATRICE 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 82...WW 83...WW 84...
DISCUSSION...VERY STRONG SYSTEM RAPIDLY MOVING NEWD ACROSS PLAIN
WITH IMPRESSIVE SHEAR ENVIRONMENT IN SUPPORT OF SUPERCELL
DEVELOPMENT. SEVERE THUNDERSTORMS HAVE DEVELOPED ALONG/AHEAD OF DRY
LINE/COLD FRONT SERN SD/ERN NE AND WILL CONTINUE TO INTENSIFY AND
BECOME MORE NUMEROUS AS 90KT 500 MB WIND MAX CROSSES AREA THIS
EVENING. MDT INSTABILITY WITH MLCAPES TO 2000 J/KG SUPPORTS
TORNADOES AND VERY LARGE HAIL WITH THE SUPERCELLS WITH DAMAGING
WINDS ENHANCED BY THE RAPID STORM MOTION.
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 550.
MEAN STORM MOTION VECTOR 24045.
...HALES
440,0923 400,0955 400,0985 440,0954SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 17, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Cerro Gordo, Chickasaw, Emmet, Floyd, Hancock and 7 more | 5 hr |
| Apr 17, 9:31 PM CDT | Mesoscale Discussion | SPC | Allamakee, Cerro Gordo, Chickasaw, Emmet, Fayette, Floyd and 8 more | 119 min |
| Apr 17, 10:05 PM CDT | Tornado Watch | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 19 more | 5 hr |
| Apr 17, 11:10 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Dickinson, Lyon, O'Brien and 3 more | 95 min |
| Apr 17, 11:35 PM CDT | Severe Thunderstorm Watch | SPC | Clay, Dickinson, Lyon, O'Brien, Osceola, Sioux | 5 hr |
| Apr 17, 11:50 PM CDT | Mesoscale Discussion | SPC | Cerro Gordo, Emmet, Hancock, Howard, Humboldt, Kossuth and 5 more | 85 min |
| Apr 18, 4:15 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Calhoun, Cerro Gordo, Cherokee, Clay, Dickinson and 20 more | 60 min |
| Apr 18, 12:30 AM CDT | Severe Thunderstorm Watch | SPC | Anoka, Carver, Chisago, Dakota, Goodhue, Hennepin and 11 more | 5 hr |
| Apr 18, 2:37 AM CDT | Mesoscale Discussion | SPC | Aitkin, Anoka, Benton, Big Stone, Brown, Carlton and 40 more | 53 min |
| Apr 18, 4:43 AM CDT | Mesoscale Discussion | SPC | Aitkin, Benton, Carlton, Cass, Chisago, Crow Wing and 15 more | 32 min |
| Apr 18, 8:04 AM CDT | Mesoscale Discussion | SPC | Aitkin, Benton, Carlton, Cass, Crow Wing, Douglas and 6 more | 86 min |
| Apr 18, 12:39 PM CDT | Mesoscale Discussion | SPC | Aitkin, Anoka, Benton, Big Stone, Carlton, Carver and 32 more | 2 hr |
| Apr 18, 1:40 PM CDT | Tornado Watch | SPC | Aitkin, Anoka, Benton, Carlton, Carver, Chippewa and 32 more | 6 hr |
| Apr 18, 2:20 PM CDT | Severe Thunderstorm Watch | SPC | Lincoln, Lyon, Pipestone, Rock | 6 hr |
| Apr 18, 3:33 PM CDT | Mesoscale Discussion | SPC | Aitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 12 more | 117 min |
| Apr 18, 5:23 PM CDT | Mesoscale Discussion | SPC | Lincoln, Lyon, Pipestone, Rock | 2 hr |
| Apr 18, 6:35 PM CDT | Tornado Watch | SPC | Brown, Carver, Dakota, Goodhue, Hennepin, Le Sueur and 7 more | 5 hr |
| Apr 18, 1:42 PM CDT | Mesoscale Discussion | SPC | Arthur, Blaine, Boyd, Brown, Cherry, Grant and 10 more | 3 hr |
Nearby
Tornado Watches in Iowa, 2004Tornado Watches in Nebraska, 2004Tornado Watches in Minnesota, 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.