Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 408

April 11, 201134 counties in Arkansas; Bossier Parish, Caddo Parish, Webster Parish, Louisiana; 13 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 4:19 AM CDT for 34 counties in Arkansas; Bossier Parish, Caddo Parish, Webster Parish, Louisiana; 13 counties in Texas. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 11, 2011, 4:19 AM CDT (09:19 UTC)
Expired
Apr 11, 2011, 5:15 AM CDT
In force
56 min
Issued by
the Storm Prediction Center
All 50 counties

Calhoun County, AR, Clark County, AR, Cleburne County, AR, Cleveland County, AR, Columbia County, AR, Conway County, AR, Dallas County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Pike County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Sevier County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Bossier Parish, LA, Caddo Parish, LA, Webster Parish, LA, Bowie County, TX, Camp County, TX, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Panola County, TX, Rusk County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Wood County, TX

The radar

The Little Rock radar (KLZK), 117 km from the middle of the area, began a volume at 09:20 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 nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 9.3 hours before the alert went out and 185 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 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 433 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 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
433 J/kg
Mixed-layer CIN
-317 J/kg
Mixed-layer LCL
1903 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
149 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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, 9:46 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 10 more29 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 10, 7:02 PM CDTSevere Thunderstorm WatchSPCBosque, Brown, Callahan, Coleman, Collin, Comanche and 41 more8 hr
Apr 10, 9:09 PM CDTMesoscale DiscussionSPCBrown, Callahan, Coleman, Comanche, Concho, Cooke and 21 more66 min
Apr 10, 11:39 PM CDTTornado WatchSPCAnderson, Bandera, Bell, Blanco, Bosque, Burnet and 28 more7 hr
Apr 11, 1:27 AM CDTMesoscale DiscussionSPCAnderson, Bell, Blanco, Bosque, Brown, Burnet and 36 more93 min

Nearby

Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Texas, 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.