Alert archive / Iowa / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 262

May 8, 20027 counties in Illinois; 21 counties in Iowa; Clark County, Scotland County, Missouri

The Storm Prediction Center issued this severe thunderstorm watch at May 8, 2002, 9:00 PM CDT for 7 counties in Illinois; 21 counties in Iowa; Clark County, Scotland County, Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
May 8, 2002, 9:00 PM CDT (02:00 UTC)
Expired
May 9, 2002, 2:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 30 counties

Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Hancock County, IL, Henderson County, IL, Jo Daviess County, IL, McDonough County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL, Clark County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 90 km from the middle of the area, began a volume at 02:00 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

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

IssuedProductOfficeCountiesLasted
May 8, 9:07 PM CDTTornado WarningDVNIowa, Keokuk68 min
May 8, 10:00 PM CDTSevere Thunderstorm WarningDVNClinton, Jackson60 min
May 8, 10:06 PM CDTSevere Thunderstorm WarningDVNJohnson39 min

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.0 hours before the alert went out and 96 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, Davenport, at 00:00Z on 2002-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1642 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, Davenport, at 00:00Z on 2002-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 108 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
1642 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
951 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
227 m²/s²
Significant tornado parameter
1.3
Supercell composite
6.8

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 090150
SEL2  
SPC WW 090143
IAZ000-ILZ000-MOZ000-090700-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 262
STORM PREDICTION CENTER NORMAN OK
843 PM CDT WED MAY 8 2002

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

   EASTERN IOWA                               
   NORTHWEST ILLINOIS                           
   EXTREME NORTHEAST MISSOURI                           

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 900 PM
UNTIL 200 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 55 STATUTE MILES
EAST AND WEST OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF BURLINGTON
IOWA TO 15 MILES WEST NORTHWEST OF DUBUQUE 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.

OTHER WATCH INFORMATION...  CONTINUE...WW 255...WW 256...WW
257...WW 258...WW 259...WW 260...WW 261...

DISCUSSION...LINE OF STRONG/SEVERE STORMS OVER CENTRAL IA WILL
CONTINUE TO TRACK EASTWARD TOWARD THE MS RIVER.  BOW ECHOES AND
ASSOCIATED DAMAGING WINDS APPEAR TO BE THE PRIMARY THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 24035.

...HART

422,0895 401,0902 401,0922 422,0920

WWUS20 KWNS 090150
SEL2  
SPC WW 090143
IAZ000-ILZ000-MOZ000-090700-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 262
STORM PREDICTION CENTER NORMAN OK
843 PM CDT WED MAY 8 2002

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

   EASTERN IOWA                               
   NORTHWEST ILLINOIS                           
   EXTREME NORTHEAST MISSOURI                           

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 900 PM
UNTIL 200 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 55 STATUTE MILES
EAST AND WEST OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF BURLINGTON
IOWA TO 15 MILES WEST NORTHWEST OF DUBUQUE 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.

OTHER WATCH INFORMATION...  CONTINUE...WW 255...WW 256...WW
257...WW 258...WW 259...WW 260...WW 261...

DISCUSSION...LINE OF STRONG/SEVERE STORMS OVER CENTRAL IA WILL
CONTINUE TO TRACK EASTWARD TOWARD THE MS RIVER.  BOW ECHOES AND
ASSOCIATED DAMAGING WINDS APPEAR TO BE THE PRIMARY THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 24035.

...HART

422,0895 401,0902 401,0922 422,0920

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 8, 8:30 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 6 more6 hr
May 8, 11:30 PM CDTSevere Thunderstorm WatchSPCChampaign, DeWitt, Douglas, Edgar, Ford, Iroquois and 12 more5 hr
May 9, 2:30 AM CDTSevere Thunderstorm WatchSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 9 more6 hr
May 8, 8:00 PM CDTSevere Thunderstorm WatchSPCBarton, Bates, Benton, Camden, Cedar, Christian and 11 more6 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2002Severe Thunderstorm Watches in Illinois, 2002Severe Thunderstorm Watches in Missouri, 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.