Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 2158

October 29, 200929 counties in Arkansas; 16 parishes in Louisiana; 30 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Oct 29, 2009, 3:03 PM CDT for 29 counties in Arkansas; 16 parishes in Louisiana; 30 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Oct 29, 2009, 3:03 PM CDT (20:03 UTC)
Expired
Oct 29, 2009, 5:00 PM CDT
In force
117 min
Issued by
the Storm Prediction Center
All 75 counties

Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln 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, Polk County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sevier County, AR, Union County, AR, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Houston County, TX, Jasper County, TX, Liberty County, TX, Marion County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX, Walker County, TX

The radar

The Shreveport radar (KSHV), 62 km from the middle of the area, began a volume at 20:04 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, 8.1 hours before the alert went out and 70 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 2009-10-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 387 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 2009-10-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 350 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
387 J/kg
Mixed-layer CIN
-88 J/kg
Mixed-layer LCL
453 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
350 m²/s²
0-3 km storm-relative helicity
422 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.7

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
Oct 29, 1:14 PM CDTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more8 hr
Oct 29, 1:51 PM CDTTornado WatchSPCBradley, Calhoun, Clark, Cleveland, Dallas, Garland and 13 more7 hr
Oct 29, 1:57 PM CDTMesoscale DiscussionSPCWashington2 hr
Oct 29, 5:24 PM CDTMesoscale DiscussionSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more66 min
Oct 29, 5:27 PM CDTTornado WatchSPCBaxter, Boone, Carroll, Cleburne, Conway, Crawford and 22 more3 hr
Oct 29, 10:48 AM CDTMesoscale DiscussionSPCAllen, Beauregard, Bienville, Bossier, Caddo, De Soto and 7 more117 min
Oct 28, 7:12 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 11 more93 min
Oct 29, 1:07 AM CDTMesoscale DiscussionSPCArcher, Baylor, Bosque, Callahan, Clay, Collin and 25 more53 min
Oct 29, 1:19 AM CDTTornado WatchSPCCollin, Cooke, Dallas, Delta, Denton, Ellis and 18 more6 hr
Oct 29, 1:59 AM CDTTornado WatchSPCArcher, Baylor, Callahan, Clay, Eastland, Erath and 17 more5 hr
Oct 29, 3:40 AM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Collin, Cooke and 29 more95 min
Oct 29, 5:19 AM CDTMesoscale DiscussionSPCAustin, Brazos, Burleson, Chambers, Fort Bend, Grimes and 13 more86 min
Oct 29, 5:31 AM CDTMesoscale DiscussionSPCCollin, Cooke, Dallas, Denton, Fannin, Grayson and 7 more89 min
Oct 29, 11:51 AM CDTTornado WatchSPCAnderson, Bell, Camp, Cherokee, Collin, Dallas and 30 more6 hr
Oct 29, 5:03 PM CDTMesoscale DiscussionSPCAnderson, Camp, Cherokee, Delta, Franklin, Freestone and 16 more57 min

Nearby

Mesoscale Discussions in Texas, 2009Mesoscale Discussions in Arkansas, 2009Mesoscale Discussions in Louisiana, 2009Every mesoscale discussion in 2009

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.