Alert archive / Illinois / Mesoscale Discussions in 2013

Mesoscale Discussion 504

April 17, 201324 counties in Illinois; 22 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2013, 6:46 PM CDT for 24 counties in Illinois; 22 counties in Indiana. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Apr 17, 2013, 6:46 PM CDT (23:46 UTC)
Expired
Apr 17, 2013, 8:15 PM CDT
In force
89 min
Issued by
the Storm Prediction Center
All 46 counties

Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Fulton County, IL, Iroquois County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Sangamon County, IL, Schuyler County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Fountain County, IN, Fulton County, IN, Hamilton County, IN, Howard County, IN, Jasper County, IN, Kosciusko County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Parke County, IN, Pulaski County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Wabash County, IN, Warren County, IN, White County, IN

The radar

The Lincoln radar (KILX), 116 km from the middle of the area, began a volume at 23:48 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 12:00Z, 11.8 hours before the alert went out and 54 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 12:00Z on 2013-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2013-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
540 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
299 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.8

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 16, 8:02 PM CDTMesoscale DiscussionSPCEdwards, Gallatin, Hamilton, Hardin, Saline, Wabash and 1 more88 min
Apr 16, 8:44 PM CDTMesoscale DiscussionSPCBond, Calhoun, Champaign, Christian, Clark, Clay and 35 more2 hr
Apr 17, 8:49 AM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Cass, DeWitt, Ford and 32 more56 min
Apr 17, 9:14 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more10 hr
Apr 17, 9:30 AM CDTMesoscale DiscussionSPCHardin2 hr
Apr 17, 11:11 AM CDTTornado WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more11 hr
Apr 17, 12:39 PM CDTSevere Thunderstorm WatchSPCHardin, Pope5 hr
Apr 17, 1:33 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more57 min
Apr 17, 3:04 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Clark, Coles, Cumberland and 26 more56 min
Apr 17, 3:33 PM CDTTornado WatchSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 24 more8 hr
Apr 17, 3:38 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more97 min
Apr 17, 3:53 PM CDTMesoscale DiscussionSPCHardin, Pope67 min
Apr 17, 6:02 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Pike88 min
Apr 17, 4:39 PM CDTMesoscale DiscussionSPCBartholomew, Brown, Clay, Daviess, Dubois, Greene and 12 more96 min

Nearby

Mesoscale Discussions in Illinois, 2013Mesoscale Discussions in Indiana, 2013Every mesoscale discussion in 2013

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.