Alert archive / Iowa / Tornado Watches in 2002

Tornado Watch 452

June 21, 200236 counties in Iowa; 10 counties in Minnesota; 20 counties in South Dakota

The Storm Prediction Center issued this tornado watch at Jun 21, 2002, 5:30 PM CDT for 36 counties in Iowa; 10 counties in Minnesota; 20 counties in South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jun 21, 2002, 5:30 PM CDT (22:30 UTC)
Expired: Jun 21, 2002, 11:00 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 66 counties

Allamakee County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Clayton County, IA, Delaware County, IA, Dickinson County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Humboldt County, IA, Kossuth County, IA, Lyon County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sioux County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Cottonwood County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 88 km from the middle of the area, began a volume at 22:32 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

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

Issued	Product	Office	Counties	Lasted
Jun 21, 6:06 PM CDT	Severe Thunderstorm Warning	ARX	Chickasaw	84 min
Jun 21, 6:16 PM CDT	Tornado Warning	ARX	Chickasaw	74 min

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.5 hours before the alert went out and 221 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 450 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 214 m²/s²
Significant tornado parameter: 0.0
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 212218
SEL2  
WWUS20 KWNS 212215
SPC WW 212215
IAZ000-MNZ000-SDZ000-220400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 452
STORM PREDICTION CENTER NORMAN OK
515 PM CDT FRI JUN 21 2002

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

   NORTHERN IOWA                               
   SOUTHERN MINNESOTA                          
   SOUTHEAST SOUTH DAKOTA                       

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 530 PM UNTIL 1100
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 50 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 30 MILES WEST OF MITCHELL SOUTH DAKOTA TO 65
MILES EAST NORTHEAST OF WATERLOO 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...  CONTINUE...WW 451...

DISCUSSION...WELL DEFINED E/W BOUNDARY ACROSS NRN IA/SERN SD WILL
BE FOCUS FOR RAPID SEVERE THUNDERSTORM DEVELOPMENT.  WITH 0-1KM
SHEAR VICINITY BOUNDARY OF 150-200 HELICITY AND VERY UNSTABLE
AIRMASS...SUPERCELLS ARE VERY LIKELY.  IN ADDITION TO POTENTIAL FOR
VERY LARGE HAIL...ISOLATED TORNADOES ARE ALSO EXPECTED.


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 26020.


...HALES

421,0911 430,0983 442,0983 433,0911

Nearby

Tornado Watches in Iowa, 2002 Tornado Watches in South Dakota, 2002 Tornado Watches in Minnesota, 2002 Every 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.