Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 410

April 11, 201116 counties in Arkansas; 5 parishes in Louisiana; 43 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 9:46 AM CDT for 16 counties in Arkansas; 5 parishes in Louisiana; 43 counties in Mississippi. It was in force for 29 min.

The area

The outline as issued.

The facts

Issued
Apr 11, 2011, 9:46 AM CDT (14:46 UTC)
Expired
Apr 11, 2011, 10:15 AM CDT
In force
29 min
Issued by
the Storm Prediction Center
All 64 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Jefferson County, AR, Lincoln County, AR, Ouachita County, AR, Phillips County, AR, Union County, AR, Claiborne Parish, LA, East Carroll Parish, LA, Morehouse Parish, LA, Union Parish, LA, West Carroll Parish, LA, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Coahoma County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Kemper County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman 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, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Little Rock radar (KLZK), 172 km from the middle of the area, began a volume at 14:48 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

Jackson, MS (KJAN), launched 12:00Z, 2.8 hours before the alert went out and 173 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, Jackson, MS at 12:00Z on 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 600 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, Jackson, MS at 12:00Z on 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 220 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
600 J/kg
Mixed-layer CIN
-183 J/kg
Mixed-layer LCL
544 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
220 m²/s²
0-3 km storm-relative helicity
297 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

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.

IssuedProductOfficeCountiesLasted
Apr 10, 7:28 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 7 more8 hr
Apr 10, 8:52 PM CDTMesoscale DiscussionSPCBenton, Boone, Carroll, Crawford, Madison, Washington53 min
Apr 11, 1:49 AM CDTTornado WatchSPCHempstead, Howard, Lafayette, Little River, Miller, Nevada and 1 more4 hr
Apr 11, 2:04 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Conway, Crawford and 17 more56 min
Apr 11, 4:19 AM CDTMesoscale DiscussionSPCCalhoun, Clark, Cleburne, Cleveland, Columbia, Conway and 28 more56 min
Apr 11, 10:31 AM CDTTornado WatchSPCArkansas, Bradley, Cleveland, Crittenden, Desha, Drew and 6 more6 hr
Apr 11, 12:37 PM CDTMesoscale DiscussionSPCArkansas, Bradley, Cleveland, Crittenden, Desha, Drew and 6 more53 min
Apr 11, 8:58 AM CDTMesoscale DiscussionSPCAlcorn, Benton, Calhoun, Chickasaw, Clay, Grenada and 19 more62 min
Apr 11, 10:41 AM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 29 more64 min
Apr 11, 3:56 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Chickasaw, Choctaw, Clarke, Clay and 29 more34 min
Apr 11, 4:05 PM CDTTornado WatchSPCClarke, Covington, Forrest, Greene, Jasper, Jefferson Davis and 20 more6 hr

Nearby

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