Alert archive / Texas / Mesoscale Discussions in 2008

Mesoscale Discussion 463

March 18, 200827 counties in Arkansas; Caddo Parish, Louisiana; 42 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2008, 3:54 PM CDT for 27 counties in Arkansas; Caddo Parish, Louisiana; 42 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2008, 3:54 PM CDT (20:54 UTC)
Expired
Mar 18, 2008, 6:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 70 counties

Clark County, AR, Cleburne County, AR, Columbia 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, Lafayette County, AR, Lawrence County, AR, Little River County, AR, Lonoke County, AR, Miller 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, White County, AR, Caddo Parish, LA, Anderson County, TX, Angelina County, TX, Austin County, TX, Bowie County, TX, Brazos County, TX, Burleson County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Freestone County, TX, Gregg County, TX, Grimes County, TX, Harris County, TX, Harrison County, TX, Henderson County, TX, Houston County, TX, Leon County, TX, Liberty County, TX, Limestone County, TX, Madison County, TX, Marion County, TX, Milam County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Polk County, TX, Red River County, TX, Robertson County, TX, Rusk County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Trinity County, TX, Upshur County, TX, Van Zandt County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 66 km from the middle of the area, began a volume at 20:54 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 12:00Z, 8.9 hours before the alert went out and 75 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 12:00Z on 2008-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 682 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 12:00Z on 2008-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 356 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
682 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
741 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
356 m²/s²
0-3 km storm-relative helicity
487 m²/s²
Significant tornado parameter
1.7
Supercell composite
6.7

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
Mar 17, 7:34 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 11 more56 min
Mar 17, 9:36 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 20 more114 min
Mar 17, 10:16 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 31 more8 hr
Mar 18, 1:13 AM CDTMesoscale DiscussionSPCWashington62 min
Mar 18, 2:23 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Fulton, Madison and 2 more2 hr
Mar 18, 2:46 AM CDTMesoscale DiscussionSPCBaxter, Cleburne, Conway, Crawford, Faulkner, Franklin and 27 more89 min
Mar 18, 5:54 AM CDTMesoscale DiscussionSPCBenton, Boone, Carroll, Crawford, Madison, Washington2 hr
Mar 18, 9:26 AM CDTMesoscale DiscussionSPCCalhoun, Clark, Columbia, Conway, Dallas, Garland and 19 more2 hr
Mar 18, 10:16 AM CDTTornado Watch PDSSPCArkansas, Clark, Clay, Cleburne, Cleveland, Columbia and 48 more7 hr
Mar 18, 10:59 AM CDTTornado Watch PDSSPCUnion8 hr
Mar 18, 11:54 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 6 more3 hr
Mar 18, 12:10 PM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Cleveland, Conway, Craighead and 47 more2 hr
Mar 18, 1:51 PM CDTMesoscale DiscussionSPCPolk, Sevier3 hr
Mar 18, 4:46 PM CDTMesoscale DiscussionSPCArkansas, Clark, Clay, Craighead, Crittenden, Cross and 19 more59 min
Mar 18, 5:19 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 43 more11 hr
Mar 18, 6:06 PM CDTMesoscale DiscussionSPCClark, Clay, Cleburne, Conway, Craighead, Cross and 20 more3 hr
Mar 18, 6:47 PM CDTTornado WatchSPCUnion9 hr
Mar 18, 6:19 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 22 more56 min
Mar 17, 7:09 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Wichita, Wilbarger7 hr
Mar 17, 9:17 PM CDTMesoscale DiscussionSPCBandera, Blanco, Bosque, Brown, Burnet, Callahan and 53 more58 min
Mar 17, 10:21 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Wichita, Wilbarger54 min
Mar 17, 11:06 PM CDTMesoscale DiscussionSPCBandera, Blanco, Bosque, Brown, Burnet, Callahan and 53 more54 min
Mar 18, 1:32 AM CDTMesoscale DiscussionSPCBrown, Callahan, Coke, Coleman, Concho, Crockett and 9 more58 min
Mar 18, 1:43 AM CDTMesoscale DiscussionSPCBrown, Callahan, Coke, Coleman, Concho, Crockett and 9 more32 min
Mar 18, 1:52 AM CDTTornado WatchSPCBandera, Blanco, Bosque, Brown, Burnet, Callahan and 34 more7 hr
Mar 18, 4:57 AM CDTMesoscale DiscussionSPCBandera, Blanco, Burnet, Coryell, Gillespie, Hamilton and 7 more93 min
Mar 18, 7:22 AM CDTMesoscale DiscussionSPCAnderson, Austin, Bastrop, Bell, Brazoria, Brazos and 40 more113 min
Mar 18, 7:50 AM CDTMesoscale DiscussionSPCBandera, Bosque, Brown, Burnet, Coleman, Comanche and 19 more55 min
Mar 18, 1:19 PM CDTMesoscale DiscussionSPCAnderson, Austin, Bastrop, Bell, Brazos, Burleson and 37 more116 min

Nearby

Mesoscale Discussions in Texas, 2008Mesoscale Discussions in Arkansas, 2008Mesoscale Discussions in Louisiana, 2008Every mesoscale discussion in 2008

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.