Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 437

April 15, 20116 states

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2011, 12:29 PM CDT for 6 states. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2011, 12:29 PM CDT (17:29 UTC)
Expired
Apr 15, 2011, 1:30 PM CDT
In force
61 min
Issued by
the Storm Prediction Center
All 104 counties

Clay County, AR, Crittenden County, AR, Mississippi County, AR, Adams County, IL, Alexander County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, Fayette County, IL, Franklin County, IL, Greene County, IL, Jackson County, IL, Jefferson County, IL, Jersey County, IL, Johnson County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Massac County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Perry County, IL, Pike County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Saint Clair County, IL, Saline County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Union County, IL, Washington County, IL, Williamson County, IL, Ballard County, KY, Carlisle County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, McCracken County, KY, Audrain County, MO, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Dunklin County, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Lewis County, MO, Lincoln County, MO, Madison County, MO, Marion County, MO, Mississippi County, MO, Monroe County, MO, Montgomery County, MO, New Madrid County, MO, Pemiscot County, MO, Perry County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Shelby County, MO, Stoddard County, MO, Warren County, MO, Washington County, MO, Wayne County, MO, Alcorn County, MS, Benton County, MS, DeSoto County, MS, Lafayette County, MS, Marshall County, MS, Panola County, MS, Prentiss County, MS, Tate County, MS, Tippah County, MS, Union County, MS, Carroll County, TN, Chester County, TN, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Paducah radar (KPAH), 128 km from the middle of the area, began a volume at 17:29 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

Little Rock, AR (KLZK), launched 12:00Z, 5.5 hours before the alert went out and 291 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, Little Rock, AR at 12:00Z on 2011-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 41 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, Little Rock, AR at 12:00Z on 2011-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 144 square meters per square second.1939587897Sfc1 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
41 J/kg
Mixed-layer CIN
-230 J/kg
Mixed-layer LCL
565 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
144 m²/s²
0-3 km storm-relative helicity
98 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 14, 7:33 PM CDTMesoscale DiscussionSPCBoone, Calhoun, Carroll, Clark, Cleburne, Cleveland and 34 more117 min
Apr 14, 9:06 PM CDTTornado WatchSPCBaxter, Benton, Boone, Bradley, Calhoun, Carroll and 45 more6 hr
Apr 14, 11:11 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clark, Cleburne and 35 more94 min
Apr 15, 1:27 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleburne and 33 more93 min
Apr 15, 2:19 AM CDTTornado WatchSPCArkansas, Ashley, Baxter, Bradley, Calhoun, Chicot and 38 more8 hr
Apr 15, 2:09 PM CDTTornado WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 3 more7 hr
Apr 15, 3:32 PM CDTMesoscale DiscussionSPCClay, Greene58 min
Apr 15, 5:57 PM CDTMesoscale DiscussionSPCMississippi2 hr
Apr 15, 12:47 PM CDTTornado WatchSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 57 more9 hr
Apr 15, 4:21 AM CDTMesoscale DiscussionSPCAdams, Alcorn, Attala, Benton, Bolivar, Calhoun and 46 more84 min
Apr 15, 7:32 AM CDTTornado WatchSPCAdams, Amite, Attala, Carroll, Choctaw, Claiborne and 45 more7 hr
Apr 15, 10:28 AM CDTMesoscale DiscussionSPCAdams, Amite, Attala, Choctaw, Claiborne, Clarke and 41 more2 hr
Apr 15, 11:21 AM CDTTornado WatchSPCGeorge, Greene, Perry, Stone, Wayne9 hr
Apr 15, 1:30 PM CDTMesoscale DiscussionSPCAdams, Amite, Attala, Chickasaw, Choctaw, Claiborne and 44 more2 hr
Apr 15, 2:41 PM CDTTornado WatchSPCAdams, Amite, Attala, Carroll, Choctaw, Claiborne and 42 more7 hr
Apr 15, 3:35 PM CDTMesoscale DiscussionSPCAdams, Amite, Attala, Carroll, Chickasaw, Choctaw and 46 more85 min
Apr 15, 6:09 PM CDTMesoscale DiscussionSPCAmite, Attala, Choctaw, Clarke, Copiah, Covington and 29 more96 min

Nearby

Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Missouri, 2011Mesoscale Discussions in Tennessee, 2011Every 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.