Alert archive / Iowa / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 118

April 18, 20024 counties in Illinois; 31 counties in Iowa; 16 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at Apr 18, 2002, 8:30 PM CDT for 4 counties in Illinois; 31 counties in Iowa; 16 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2002, 8:30 PM CDT (01:30 UTC)
Expired
Apr 19, 2002, 1:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 51 counties

Appanoose County, IA, Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Davis County, IA, Decatur 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, Lucas County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Wayne County, IA, Carroll County, IL, Jo Daviess County, IL, Rock Island County, IL, Stephenson County, IL, Adair County, MO, Clark County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Knox County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 130 km from the middle of the area, began a volume at 01:30 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

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

IssuedProductOfficeCountiesLasted
Apr 18, 8:32 PM CDTSevere Thunderstorm WarningEAXHarrison58 min
Apr 18, 8:35 PM CDTTornado WarningDVNJones, Linn35 min
Apr 18, 8:44 PM CDTSevere Thunderstorm WarningDVNDubuque31 min
Apr 18, 8:59 PM CDTTornado WarningDVNJohnson46 min
Apr 18, 9:00 PM CDTSevere Thunderstorm WarningEAXMercer60 min
Apr 18, 9:08 PM CDTSevere Thunderstorm WarningEAXGentry37 min
Apr 18, 9:10 PM CDTSevere Thunderstorm WarningDMXMahaska50 min
Apr 18, 9:16 PM CDTSevere Thunderstorm WarningDVNJo Daviess44 min
Apr 18, 9:28 PM CDTTornado WarningDVNCedar32 min
Apr 18, 9:30 PM CDTSevere Thunderstorm WarningDVNClinton, Jones45 min
Apr 18, 9:30 PM CDTSevere Thunderstorm WarningEAXHarrison60 min
Apr 18, 9:50 PM CDTSevere Thunderstorm WarningDVNScott40 min
Apr 18, 9:55 PM CDTSevere Thunderstorm WarningEAXGrundy65 min
Apr 18, 9:59 PM CDTSevere Thunderstorm WarningDVNCarroll, Jo Daviess, Stephenson51 min

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.5 hours before the alert went out and 204 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 2002-04-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1636 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 2002-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 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
1636 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1702 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
200 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 19, 8:00 AM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Christian, Clinton, Fayette, Greene and 13 more5 hr
Apr 19, 10:15 AM CDTSevere Thunderstorm WatchSPCBond, Clinton, Fayette, Franklin, Jackson, Jefferson and 10 more6 hr
Apr 19, 2:15 PM CDTSevere Thunderstorm WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 17 more6 hr
Apr 19, 5:30 PM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Christian, Clay, Clinton, DeWitt and 20 more5 hr
Apr 19, 5:00 AM CDTSevere Thunderstorm WatchSPCBates, Benton, Buchanan, Caldwell, Camden, Carroll and 17 more5 hr
Apr 19, 4:00 PM CDTSevere Thunderstorm WatchSPCBarry, Barton, Bates, Benton, Boone, Callaway and 44 more6 hr

Nearby

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