Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 2091

October 17, 200711 counties in Arkansas; 36 parishes in Louisiana; 8 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Oct 17, 2007, 9:36 AM CDT for 11 counties in Arkansas; 36 parishes in Louisiana; 8 counties in Texas. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Oct 17, 2007, 9:36 AM CDT (14:36 UTC)
Expired
Oct 17, 2007, 11:30 AM CDT
In force
114 min
Issued by
the Storm Prediction Center
All 55 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Drew County, AR, Lafayette County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX

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, 2.6 hours before the alert went out and 134 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 2007-10-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 865 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 2007-10-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 square meters per square second.19395878Sfc1 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
865 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
477 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
140 m²/s²
0-3 km storm-relative helicity
170 m²/s²
Significant tornado parameter
0.6
Supercell composite
4.6

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
Oct 17, 10:24 AM CDTMesoscale DiscussionSPCBenton, Washington96 min
Oct 17, 10:43 AM CDTTornado WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more7 hr
Oct 17, 11:13 AM CDTTornado WatchSPCColumbia, Hempstead, Lafayette, Little River, Miller, Nevada and 1 more7 hr
Oct 17, 2:36 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Clark, Cleveland, Columbia and 14 more114 min
Oct 17, 4:31 PM CDTTornado WatchSPCArkansas, Baxter, Benton, Boone, Bradley, Calhoun and 55 more7 hr
Oct 17, 5:15 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Chicot, Crittenden, Cross, Desha and 7 more2 hr
Oct 16, 10:36 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 27 more114 min
Oct 16, 11:45 PM CDTSevere Thunderstorm WatchSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hansford and 10 more2 hr
Oct 17, 1:12 AM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 24 more93 min
Oct 17, 1:36 AM CDTTornado WatchSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 18 more7 hr
Oct 17, 1:44 AM CDTSevere Thunderstorm WatchSPCHansford, Hutchinson, Lipscomb, Moore, Ochiltree, Potter and 3 more7 hr
Oct 17, 4:41 AM CDTMesoscale DiscussionSPCArcher, Baylor, Borden, Brown, Callahan, Coke and 32 more2 hr
Oct 17, 6:07 AM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Childress, Collingsworth, Cottle, Crosby and 19 more113 min
Oct 17, 6:50 AM CDTMesoscale DiscussionSPCHansford, Hutchinson, Lipscomb, Moore, Ochiltree, Potter and 2 more100 min
Oct 17, 7:43 AM CDTTornado WatchSPCArcher, Baylor, Clay, Foard, Hardeman, Knox and 2 more7 hr
Oct 17, 1:20 PM CDTMesoscale DiscussionSPCCollin, Delta, Fannin, Grayson, Hunt, Lamar and 1 more85 min

Nearby

Mesoscale Discussions in Louisiana, 2007Mesoscale Discussions in Arkansas, 2007Mesoscale Discussions in Texas, 2007Every mesoscale discussion in 2007

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.