Alert archive / Illinois / Mesoscale Discussions in 2013

Mesoscale Discussion 507

April 17, 201327 counties in Illinois; 16 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2013, 8:21 PM CDT for 27 counties in Illinois; 16 counties in Indiana. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Apr 17, 2013, 8:21 PM CDT (01:21 UTC)
Expired
Apr 17, 2013, 9:45 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 43 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, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Fountain County, IN, Howard County, IN, Jasper County, IN, Montgomery County, IN, Newton County, IN, Parke County, IN, Pulaski County, IN, Tippecanoe County, IN, Vermillion County, IN, Warren County, IN, White County, IN

The radar

The Lincoln radar (KILX), 85 km from the middle of the area, began a volume at 01:22 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

Lincoln, IL (KILX), launched 00:00Z, 1.4 hours before the alert went out and 24 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 2013-04-18Temperature 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 00:00Z on 2013-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 356 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
412 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
356 m²/s²
0-3 km storm-relative helicity
444 m²/s²
Significant tornado parameter
0.0
Supercell composite
11.4

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 17, 8:53 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Pike, Scott97 min
Apr 17, 9:57 PM CDTTornado WatchSPCAdams, Brown, Pike7 hr
Apr 17, 10:48 PM CDTMesoscale DiscussionSPCChampaign, Christian, Coles, DeWitt, Douglas, Edgar and 12 more57 min
Apr 17, 11:46 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Morgan, Pike, Scott89 min
Apr 18, 2:01 AM CDTMesoscale DiscussionSPCCalhoun, Jersey89 min
Apr 18, 4:02 AM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Monroe58 min
Apr 18, 5:36 AM CDTMesoscale DiscussionSPCBond, Clinton, Fayette, Madison, Monroe, Montgomery and 3 more54 min
Apr 18, 5:42 AM CDTTornado WatchSPCBond, Clinton, Fayette, Jersey, Macoupin, Madison and 6 more8 hr
Apr 18, 7:25 AM CDTMesoscale DiscussionSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 17 more95 min
Apr 18, 8:31 AM CDTTornado Watch PDSSPCClark, Clay, Coles, Crawford, Cumberland, Douglas and 6 more7 hr
Apr 18, 9:25 AM CDTTornado WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more8 hr
Apr 18, 11:14 AM CDTMesoscale DiscussionSPCClark, Clay, Crawford, Jasper, Lawrence, Marion and 4 more2 hr
Apr 18, 12:48 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more87 min
Apr 18, 2:47 PM CDTMesoscale DiscussionSPCClark, Crawford, Lawrence88 min
Apr 18, 3:32 PM CDTTornado WatchSPCAdams, Bartholomew, Blackford, Boone, Brown, Clay and 27 more3 hr
Apr 18, 5:33 PM CDTMesoscale DiscussionSPCAdams, Allen, Bartholomew, Blackford, Boone, Brown and 43 more117 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.