Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 1862

August 3, 20049 counties in Illinois; 38 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2004, 5:39 PM CDT for 9 counties in Illinois; 38 counties in Iowa. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Aug 3, 2004, 5:39 PM CDT (22:39 UTC)
Expired
Aug 3, 2004, 6:45 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 47 counties

Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Clinton County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Grundy County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Polk County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Knox County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL, Whiteside County, IL

The radar

The Quad Cities radar (KDVN), 129 km from the middle of the area, began a volume at 22:41 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.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.7 hours before the alert went out and 136 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 12:00Z on 2004-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 760 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 12:00Z on 2004-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
760 J/kg
Mixed-layer CIN
-200 J/kg
Mixed-layer LCL
1021 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
16 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 3, 8:40 AM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Monroe and 2 more5 hr
Aug 3, 11:22 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Jersey, Monroe, Pike and 1 more83 min
Aug 3, 3:55 PM CDTMesoscale DiscussionSPCAdams, Carroll, Fulton, Hancock, Henderson, Henry and 7 more95 min
Aug 3, 4:25 PM CDTTornado WatchSPCBureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 7 more6 hr
Aug 3, 6:34 PM CDTMesoscale DiscussionSPCBureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 7 more86 min
Aug 3, 2:02 AM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Buena Vista, Butler, Calhoun and 30 more118 min
Aug 3, 7:21 AM CDTMesoscale DiscussionSPCLyon54 min
Aug 3, 10:48 AM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buchanan, Buena Vista, Butler and 32 more87 min
Aug 3, 11:05 AM CDTSevere Thunderstorm WatchSPCBremer, Buena Vista, Butler, Calhoun, Cerro Gordo, Cherokee and 25 more6 hr
Aug 3, 1:16 PM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Bremer, Buchanan, Buena Vista and 46 more89 min
Aug 3, 2:25 PM CDTSevere Thunderstorm WatchSPCAllamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 7 more5 hr
Aug 3, 3:00 PM CDTMesoscale DiscussionSPCAdair, Audubon, Carroll, Cass, Crawford, Greene and 8 more2 hr
Aug 3, 4:52 PM CDTMesoscale DiscussionSPCAdams, Audubon, Cass, Fremont, Harrison, Mills and 5 more53 min
Aug 3, 5:00 PM CDTTornado WatchSPCAdair, Adams, Audubon, Cass, Fremont, Guthrie and 9 more5 hr
Aug 3, 5:07 PM CDTMesoscale DiscussionSPCAllamakee, Clayton, Fayette, Winneshiek53 min
Aug 3, 6:45 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Fremont, Guthrie and 9 more90 min

Nearby

Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Illinois, 2004Every mesoscale discussion 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.