Alert archive / Iowa / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 710

October 1, 200247 counties in Iowa; 8 counties in Nebraska; Lincoln County, Union County, South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Oct 1, 2002, 3:30 PM CDT for 47 counties in Iowa; 8 counties in Nebraska; Lincoln County, Union County, South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Oct 1, 2002, 3:30 PM CDT (20:30 UTC)
Expired
Oct 1, 2002, 9:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 57 counties

Adair County, IA, Audubon County, IA, Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dallas County, IA, Dickinson County, IA, Emmet County, IA, Franklin County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Jasper County, IA, Kossuth County, IA, Lyon County, IA, Madison County, IA, Marion County, IA, Marshall County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Story County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Burt County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Thurston County, NE, Washington County, NE, Lincoln County, SD, Union County, SD

The radar

The Des Moines radar (KDMX), 158 km from the middle of the area, began a volume at 20:34 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

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

IssuedProductOfficeCountiesLasted
Oct 1, 3:34 PM CDTSevere Thunderstorm WarningFSDO'Brien41 min
Oct 1, 4:20 PM CDTSevere Thunderstorm WarningFSDClay40 min
Oct 1, 4:44 PM CDTSevere Thunderstorm WarningDMXPalo Alto46 min
Oct 1, 5:20 PM CDTSevere Thunderstorm WarningOAXPottawattamie40 min
Oct 1, 6:00 PM CDTSevere Thunderstorm WarningOAXDouglas45 min
Oct 1, 6:10 PM CDTSevere Thunderstorm WarningOAXPottawattamie35 min
Oct 1, 6:16 PM CDTSevere Thunderstorm WarningOAXWashington44 min
Oct 1, 6:18 PM CDTSevere Thunderstorm WarningOAXHarrison, Shelby42 min
Oct 1, 6:45 PM CDTTornado WarningOAXHarrison45 min
Oct 1, 6:45 PM CDTTornado WarningOAXHarrison45 min
Oct 1, 7:07 PM CDTSevere Thunderstorm WarningDMXCrawford53 min
Oct 1, 7:10 PM CDTSevere Thunderstorm WarningOAXMonona50 min
Oct 1, 7:16 PM CDTSevere Thunderstorm WarningDMXCarroll44 min
Oct 1, 8:19 PM CDTSevere Thunderstorm WarningDMXAdair26 min
Oct 1, 8:44 PM CDTSevere Thunderstorm WarningDMXMadison31 min

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.5 hours before the alert went out and 168 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 2002-10-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 976 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2002-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 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
976 J/kg
Mixed-layer CIN
-220 J/kg
Mixed-layer LCL
1127 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

000
WWUS20 KWNS 012027
SEL0  
SPC WW 012030
IAZ000-NEZ000-020200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 710
STORM PREDICTION CENTER NORMAN OK
330 PM CDT TUE OCT 1 2002

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   WESTERN AND CENTRAL IOWA                               
   EASTERN NEBRASKA                           

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 330 PM UNTIL 900
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 80 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 25 MILES WEST OF SIOUX CITY IOWA TO
65 MILES SOUTH SOUTHEAST OF MASON CITY IOWA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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.  SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

DISCUSSION...CLUSTER OF INTENSE THUNDERSTORMS IS ONGOING OVER
NORTHWEST IA...WHILE OTHER STORMS ARE EXPECTED TO DEVELOP IN THE
NEXT 1-2 HOURS OVER EASTERN NEB.  MODERATELY UNSTABLE
AIRMASS...COUPLED WITH 40-50 KNOT 6KM SHEAR VALUES SUGGEST THE
POTENTIAL FOR SUPERCELL STORMS PRODUCING LARGE HAIL AND DAMAGING
WINDS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 26035.

...HART

433,0965 432,0925 410,0925 411,0965

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 1, 4:35 PM CDTSevere Thunderstorm WatchSPCFremont, Mills, Montgomery, Page6 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2002Severe Thunderstorm Watches in Nebraska, 2002Severe Thunderstorm Watches in South Dakota, 2002Every severe thunderstorm 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.