Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 949

May 25, 20116 states

The Storm Prediction Center issued this mesoscale discussion at May 25, 2011, 7:31 AM CDT for 6 states. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: May 25, 2011, 7:31 AM CDT (12:31 UTC)
Expired: May 25, 2011, 8:30 AM CDT
In force: 59 min
Issued by: the Storm Prediction Center

All 68 counties

Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Mississippi County, AR, Poinsett County, AR, Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Posey County, IN, Vanderburgh County, IN, Warrick County, IN, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Perry County, MO, Scott County, MO, Stoddard County, MO, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Haywood County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Paducah radar (KPAH), 76 km from the middle of the area, began a volume at 12:35 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.

Tornado Watch 370May 25, 11:10 AM CDT

The nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 0.5 hours before the alert went out and 201 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2124 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 600 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 445 m²/s²
0-3 km storm-relative helicity: 413 m²/s²
Significant tornado parameter: 6.0
Supercell composite: 20.1

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.

Issued	Product	Office	Counties	Lasted
May 24, 7:42 PM CDT	Mesoscale Discussion	SPC	Benton, Crawford, Little River, Polk, Scott, Sebastian and 2 more	63 min
May 24, 8:05 PM CDT	Tornado Watch	SPC	Baxter, Benton, Boone, Carroll, Clark, Conway and 30 more	7 hr
May 24, 11:24 PM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Clark, Conway, Franklin and 21 more	96 min
May 25, 12:48 AM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Fulton, Greene, Independence, Jackson and 4 more	57 min
May 25, 9:54 AM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Clay, Cleburne, Conway and 33 more	96 min
May 25, 10:18 AM CDT	Mesoscale Discussion	SPC	Fulton, Independence, Izard, Jackson, St. Francis, Sharp and 2 more	57 min
May 25, 10:37 AM CDT	Tornado Watch	SPC	Baxter, Boone, Carroll, Fulton, Izard, Madison and 5 more	7 hr
May 25, 11:02 AM CDT	Mesoscale Discussion	SPC	Clay	28 min
May 25, 11:52 AM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Clay, Cleburne, Cleveland, Conway and 38 more	83 min
May 25, 12:28 PM CDT	Tornado Watch PDS	SPC	Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 41 more	8 hr
May 25, 1:53 PM CDT	Mesoscale Discussion	SPC	Bradley, Calhoun, Clark, Columbia, Dallas, Hempstead and 9 more	2 hr
May 25, 2:56 PM CDT	Mesoscale Discussion	SPC	Arkansas, Calhoun, Clark, Clay, Cleburne, Cleveland and 33 more	94 min
May 25, 3:10 PM CDT	Mesoscale Discussion	SPC	Clay	95 min
May 25, 3:16 PM CDT	Tornado Watch	SPC	Ashley, Chicot, Columbia, Lafayette, Miller, Nevada and 1 more	7 hr
May 25, 5:56 PM CDT	Mesoscale Discussion	SPC	Arkansas, Craighead, Crittenden, Cross, Greene, Lee and 5 more	64 min
May 25, 1:22 AM CDT	Tornado Watch	SPC	Adams, Brown, Calhoun, Cass, Fulton, Greene and 16 more	7 hr
May 25, 4:58 AM CDT	Mesoscale Discussion	SPC	Bond, Brown, Calhoun, Cass, Champaign, Christian and 45 more	92 min
May 25, 5:46 AM CDT	Tornado Watch	SPC	Bond, Champaign, Christian, Clark, Clay, Clinton and 35 more	7 hr
May 25, 7:48 AM CDT	Mesoscale Discussion	SPC	Champaign, Clark, Clay, Clinton, Coles, Crawford and 18 more	87 min
May 25, 8:33 AM CDT	Mesoscale Discussion	SPC	Champaign, DeWitt, Douglas, Edgar, Ford, Iroquois and 3 more	87 min
May 25, 11:09 AM CDT	Tornado Watch PDS	SPC	Alexander, Bond, Calhoun, Christian, Clark, Clay and 41 more	10 hr
May 25, 2:31 PM CDT	Tornado Watch	SPC	Bureau, Cass, Champaign, DeKalb, DeWitt, Ford and 33 more	7 hr
May 25, 2:32 PM CDT	Mesoscale Discussion	SPC	Calhoun, Greene, Jersey, Macoupin, Pike, Scott	58 min
May 25, 5:48 PM CDT	Mesoscale Discussion	SPC	Bureau, Champaign, DeKalb, DeWitt, Douglas, Ford and 19 more	117 min
May 25, 6:25 PM CDT	Mesoscale Discussion	SPC	Alexander, Clay, Clinton, Edwards, Franklin, Gallatin and 20 more	2 hr
May 25, 8:50 AM CDT	Tornado Watch	SPC	Adams, Allen, Bartholomew, Blackford, Boone, Brown and 57 more	9 hr
May 25, 12:26 PM CDT	Mesoscale Discussion	SPC	Adams, Allen, Blackford, DeKalb, Delaware, Grant and 16 more	94 min
May 25, 12:55 PM CDT	Tornado Watch	SPC	Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more	8 hr
May 25, 5:19 PM CDT	Mesoscale Discussion	SPC	Bartholomew, Blackford, Boone, Brown, Clay, Clinton and 45 more	86 min
May 25, 5:44 PM CDT	Tornado Watch PDS	SPC	Adams, Bartholomew, Blackford, Boone, Brown, Carroll and 45 more	6 hr
May 24, 7:07 PM CDT	Mesoscale Discussion	SPC	Andrew, Barton, Bates, Buchanan, Cass, Cedar and 14 more	53 min
May 24, 7:26 PM CDT	Tornado Watch	SPC	Adair, Barry, Barton, Bates, Benton, Buchanan and 48 more	7 hr
May 25, 1:28 PM CDT	Mesoscale Discussion	SPC	Adair, Audrain, Boone, Caldwell, Callaway, Camden and 44 more	92 min
May 25, 3:45 PM CDT	Mesoscale Discussion	SPC	Bedford, Benton, Cannon, Cheatham, Coffee, Davidson and 24 more	90 min

Nearby

Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Kentucky, 2011 Mesoscale Discussions in Tennessee, 2011 Every mesoscale discussion in 2011

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.