Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 1748

July 21, 20044 states

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2004, 9:03 AM CDT for 4 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Jul 21, 2004, 9:03 AM CDT (14:03 UTC)
Expired
Jul 21, 2004, 11:00 AM CDT
In force
117 min
Issued by
the Storm Prediction Center
All 115 counties

Benton County, IA, Cedar County, IA, Clinton County, IA, Des Moines 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, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Champaign County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Allen County, IN, Benton County, IN, Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, DeKalb County, IN, Delaware County, IN, Elkhart County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Hamilton County, IN, Henry County, IN, Howard County, IN, Huntington County, IN, Jasper County, IN, Jay County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Madison County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Wabash County, IN, Warren County, IN, Wells County, IN, White County, IN, Whitley County, IN, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Kalamazoo County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Quad Cities radar (KDVN), 81 km from the middle of the area, began a volume at 14:04 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

Davenport, (KDVN), launched 12:00Z, 2.1 hours before the alert went out and 75 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 2004-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2834 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 2004-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 106 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
2834 J/kg
Mixed-layer CIN
-90 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
106 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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
Jul 21, 7:53 AM CDTMesoscale DiscussionSPCBoone, DuPage, Kane, Lake, McHenry, Stephenson and 1 more2 hr
Jul 21, 9:35 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 26 more5 hr
Jul 21, 10:18 AM CDTMesoscale DiscussionSPCBureau, Cook, DeKalb, DuPage, Ford, Grundy and 14 more87 min
Jul 21, 1:01 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 25 more89 min
Jul 21, 2:35 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DeWitt, DuPage and 20 more6 hr
Jul 21, 5:09 PM CDTMesoscale DiscussionSPCBureau, DeWitt, Ford, Grundy, Iroquois, Kankakee and 13 more36 min
Jul 21, 6:20 PM CDTMesoscale DiscussionSPCClark, Coles, Edgar, Vermilion25 min
Jul 21, 6:35 PM CDTSevere Thunderstorm WatchSPCAdams, Allen, Benton, Blackford, Boone, Carroll and 30 more5 hr
Jul 20, 11:08 PM CDTMesoscale DiscussionSPCHoward, Mitchell, Winnebago, Worth97 min
Jul 21, 3:43 PM CDTMesoscale DiscussionSPCCherokee, Clay, Dickinson, Lyon, O'Brien, Osceola and 2 more92 min
Jul 21, 6:02 PM CDTMesoscale DiscussionSPCBuena Vista, Cherokee, Clay, Crawford, Dickinson, Emmet and 9 more118 min
Jul 21, 11:10 AM CDTMesoscale DiscussionSPCAlpena, Antrim, Arenac, Bay, Benzie, Cheboygan and 24 more2 hr

Nearby

Mesoscale Discussions in Illinois, 2004Mesoscale Discussions in Indiana, 2004Mesoscale Discussions in Iowa, 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.