Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 611

April 26, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2011, 11:33 PM CDT for 5 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Apr 26, 2011, 11:33 PM CDT (04:33 UTC)
Expired
Apr 27, 2011, 1:30 AM CDT
In force
117 min
Issued by
the Storm Prediction Center
All 105 counties

Colbert County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Marion County, AL, Chicot County, AR, Desha County, AR, Phillips County, AR, Beauregard Parish, LA, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Alcorn County, MS, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Jefferson County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Angelina County, TX, Brazos County, TX, Burleson County, TX, Falls County, TX, Grimes County, TX, Houston County, TX, Jasper County, TX, Lee County, TX, Leon County, TX, Madison County, TX, Milam County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Polk County, TX, Robertson County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX, Washington County, TX

The radar

The Shreveport radar (KSHV), 89 km from the middle of the area, began a volume at 04:33 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

Shreveport, LA (KSHV), launched 00:00Z, 4.6 hours before the alert went out and 82 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, Shreveport, LA at 00:00Z on 2011-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2270 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, Shreveport, LA at 00:00Z on 2011-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 281 square meters per square second.1939587897117Sfc1 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
2270 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
961 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
281 m²/s²
0-3 km storm-relative helicity
428 m²/s²
Significant tornado parameter
5.6
Supercell composite
23.5

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 26, 7:59 PM CDTMesoscale DiscussionSPCColbert, Franklin, Lamar, Lauderdale, Lawrence, Limestone and 1 more2 hr
Apr 26, 9:33 PM CDTTornado Watch PDSSPCColbert, Franklin, Lauderdale7 hr
Apr 27, 1:56 AM CDTMesoscale DiscussionSPCBibb, Blount, Cullman, Fayette, Greene, Hale and 12 more64 min
Apr 27, 2:26 AM CDTTornado WatchSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 29 more6 hr
Apr 27, 8:08 AM CDTTornado WatchSPCColbert, Cullman, DeKalb, Fayette, Franklin, Jackson and 10 more6 hr
Apr 27, 10:45 AM CDTMesoscale DiscussionSPCGreene, Lamar, Marion, Pickens, Sumter90 min
Apr 27, 11:39 AM CDTMesoscale DiscussionSPCCullman, DeKalb, Jackson, Madison, Marshall, Morgan66 min
Apr 27, 1:05 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Choctaw and 27 more85 min
Apr 27, 1:42 PM CDTTornado Watch PDSSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 41 more8 hr
Apr 27, 2:56 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Choctaw and 33 more2 hr
Apr 27, 5:01 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 38 more89 min
Apr 27, 5:41 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Crenshaw, Elmore, Lee and 6 more34 min
Apr 27, 5:52 PM CDTTornado Watch PDSSPCBarbour, Bullock, Chambers, Elmore, Lee, Macon and 5 more9 hr
Apr 27, 6:39 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 26 more66 min
Apr 26, 8:53 PM CDTMesoscale DiscussionSPCCalhoun, Clark, Columbia, Dallas, Grant, Hempstead and 10 more97 min
Apr 26, 9:13 PM CDTMesoscale DiscussionSPCArkansas, Clay, Craighead, Crittenden, Cross, Desha and 21 more62 min
Apr 26, 9:58 PM CDTTornado WatchSPCCraighead, Crittenden, Cross, Greene, Jackson, Lee and 8 more7 hr
Apr 27, 3:29 AM CDTMesoscale DiscussionSPCHempstead, Lafayette, Little River, Miller2 hr
Apr 27, 4:53 AM CDTSevere Thunderstorm WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 19 more5 hr
Apr 27, 6:25 AM CDTMesoscale DiscussionSPCArkansas, Cleburne, Crittenden, Cross, Desha, Faulkner and 15 more65 min
Apr 27, 8:40 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 28 more65 min
Apr 27, 9:48 AM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Clark, Cleveland and 10 more27 min
Apr 27, 11:02 AM CDTTornado Watch PDSSPCAshley, Chicot8 hr
Apr 27, 12:42 PM CDTSevere Thunderstorm WatchSPCBaxter, Clay, Cleburne, Conway, Craighead, Crittenden and 19 more5 hr
Apr 27, 3:06 PM CDTMesoscale DiscussionSPCClay, Craighead, Greene, Mississippi, Poinsett54 min
Apr 27, 3:29 PM CDTTornado WatchSPCMississippi5 hr
Apr 26, 9:42 PM CDTTornado WatchSPCAvoyelles, Beauregard, Rapides, Vernon7 hr
Apr 27, 6:27 PM CDTMesoscale DiscussionSPCClarke, Clay, Copiah, Covington, Forrest, Jasper and 22 more33 min
Apr 27, 6:42 PM CDTTornado WatchSPCClarke, Covington, Forrest, Jasper, Jefferson Davis, Jones and 13 more3 hr
Apr 26, 7:08 PM CDTMesoscale DiscussionSPCArcher, Baylor, Childress, Clay, Collingsworth, Foard and 13 more97 min

Nearby

Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Louisiana, 2011Mesoscale Discussions in Texas, 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.