Alert archive / Indiana / Mesoscale Discussions in 2004

Mesoscale Discussion 1868

August 3, 200420 counties in Illinois; 28 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2004, 7:38 PM CDT for 20 counties in Illinois; 28 counties in Indiana. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Aug 3, 2004, 7:38 PM CDT (00:38 UTC)
Expired
Aug 3, 2004, 8:45 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
All 48 counties

Bureau County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McLean County, IL, Ogle County, IL, Putnam County, IL, Vermilion County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Hamilton County, IN, Howard County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Starke County, IN, Tippecanoe County, IN, Tipton County, IN, Wabash County, IN, Warren County, IN, White County, IN, Whitley County, IN

The radar

The Chicago radar (KLOT), 64 km from the middle of the area, began a volume at 00:39 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.6 hours before the alert went out and 118 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, Lincoln, IL at 00:00Z on 2004-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4276 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, Lincoln, IL at 00:00Z on 2004-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 square meters per square second.193958Sfc1 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
4276 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
860 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
2.0
Supercell composite
11.6

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, 7:55 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DuPage, Ford and 21 more5 hr
Aug 3, 8:19 PM CDTMesoscale DiscussionSPCCarroll, Henry, Jo Daviess, Knox, Mercer, Rock Island and 2 more56 min
Aug 3, 9:45 PM CDTSevere Thunderstorm WatchSPCFulton, Hancock, Henderson, Henry, Knox, McDonough and 3 more5 hr
Aug 3, 9:52 PM CDTMesoscale DiscussionSPCCook, DuPage, Grundy, Kane, Kendall, Lake and 3 more53 min
Aug 3, 10:38 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 3 more67 min
Aug 3, 11:30 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Cass, Champaign, Christian and 32 more6 hr
Aug 4, 1:42 AM CDTMesoscale DiscussionSPCFulton, Henderson, Jersey, Livingston, McDonough, Mason and 5 more2 hr
Aug 4, 3:52 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Champaign, Christian and 32 more53 min
Aug 4, 3:39 PM CDTMesoscale DiscussionSPCHardin, Massac, Pope96 min
Aug 3, 10:35 PM CDTSevere Thunderstorm WatchSPCAdams, Allen, Benton, Blackford, Carroll, Cass and 26 more5 hr
Aug 3, 11:47 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cass, Elkhart, Fulton, Kosciusko and 9 more58 min
Aug 4, 1:15 AM CDTMesoscale DiscussionSPCAdams, Allen, Benton, Blackford, Carroll, Cass and 26 more90 min
Aug 4, 5:44 AM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, Boone, Carroll, Clay and 28 more2 hr
Aug 4, 1:01 PM CDTMesoscale DiscussionSPCClark, Crawford, Dubois, Floyd, Harrison, Jefferson and 7 more89 min
Aug 4, 1:30 PM CDTSevere Thunderstorm WatchSPCClark, Crawford, Floyd, Harrison, Perry6 hr

Nearby

Mesoscale Discussions in Indiana, 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.