Alert archive / Illinois / Mesoscale Discussions in 2003

Mesoscale Discussion 640

April 30, 20038 states

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2003, 1:22 PM EDT for 8 states. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2003, 1:22 PM EDT (17:22 UTC)
Expired
Apr 30, 2003, 3:15 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
All 112 counties

Bartow County, GA, Catoosa County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Polk County, GA, Rabun County, GA, Towns County, GA, Union County, GA, Walker County, GA, White County, GA, Whitfield County, GA, Des Moines County, IA, Henry County, IA, Lee County, IA, Adams County, IL, Brown County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Henderson County, IL, Iroquois County, IL, Jackson County, IL, Johnson County, IL, Knox County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Pope County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Williamson County, IL, Woodford County, IL, Livingston County, KY, Lyon County, KY, Trigg County, KY, City of Saint Louis, MO, Clark County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Yancey County, NC, Bedford County, TN, Cannon County, TN, Carter County, TN, Cheatham County, TN, Cocke County, TN, Coffee County, TN, Davidson County, TN, Grundy County, TN, Hamilton County, TN, Johnson County, TN, Marion County, TN, Montgomery County, TN, Rutherford County, TN, Sequatchie County, TN, Unicoi County, TN, Washington County, TN, Williamson County, TN, Grayson County, VA

The radar

The Louisville radar (KLVX), 77 km from the middle of the area, began a volume at 17:22 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

Nashville Metro, TN (KBNA), launched 12:00Z, 5.4 hours before the alert went out and 153 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, Nashville Metro, TN at 12:00Z on 2003-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 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, Nashville Metro, TN at 12:00Z on 2003-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 square meters per square second.1939Sfc1 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
37 J/kg
Mixed-layer CIN
-257 J/kg
Mixed-layer LCL
1321 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
71 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
Apr 30, 12:50 PM EDTMesoscale DiscussionSPCBartow, Cherokee, Dawson, Fannin, Floyd, Gilmer and 9 more115 min
Apr 30, 12:04 PM EDTMesoscale DiscussionSPCBoone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 10 more116 min
Apr 30, 2:00 PM EDTSevere Thunderstorm WatchSPCAdams, Brown, Bureau, Cass, Champaign, DeWitt and 30 more5 hr
Apr 30, 4:24 PM EDTMesoscale DiscussionSPCAdams, Brown, Bureau, Cass, Champaign, DeWitt and 32 more2 hr
Apr 30, 6:15 PM EDTTornado WatchSPCAdams, Hancock, Henderson, McDonough, Mercer, Rock Island and 2 more6 hr
Apr 30, 6:50 PM EDTSevere Thunderstorm WatchSPCBureau, Cook, DeKalb, DuPage, Grundy, Henry and 15 more5 hr
Apr 29, 8:00 PM EDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 13 more3 hr
Apr 29, 8:30 PM EDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 17 more7 hr
Apr 29, 11:40 PM EDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 17 more2 hr
Apr 30, 3:49 PM EDTMesoscale DiscussionSPCAppanoose, Clarke, Decatur, Lucas, Monroe, Page and 3 more116 min
Apr 29, 11:04 PM EDTMesoscale DiscussionSPCChristian, Hopkins, Logan, Muhlenberg, Simpson, Todd2 hr
Apr 29, 9:45 PM EDTSevere Thunderstorm WatchSPCAtchison, Holt, Nodaway5 hr

Nearby

Mesoscale Discussions in Illinois, 2003Mesoscale Discussions in Georgia, 2003Mesoscale Discussions in North Carolina, 2003Every mesoscale discussion in 2003

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.