Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 2508

November 17, 200320 parishes in Louisiana; 20 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 17, 2003, 5:07 PM CST for 20 parishes in Louisiana; 20 counties in Texas. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Nov 17, 2003, 5:07 PM CST (23:07 UTC)
Expired
Nov 17, 2003, 6:00 PM CST
In force
53 min
Issued by
the Storm Prediction Center
All 40 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Tyler 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.1 hours before the alert went out and 89 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, Lake Charles Mun, LA at 12:00Z on 2003-11-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 413 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, Lake Charles Mun, LA at 12:00Z on 2003-11-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 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
413 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
895 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.1

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
Nov 17, 8:20 AM CSTTornado WatchSPCCalcasieu5 hr
Nov 17, 12:45 PM CSTTornado WatchSPCCalcasieu5 hr
Nov 17, 2:57 PM CSTMesoscale DiscussionSPCBossier, Caddo, De Soto, Webster2 hr
Nov 17, 5:25 PM CSTMesoscale DiscussionSPCBossier, Caddo, Webster65 min
Nov 17, 5:35 PM CSTTornado WatchSPCBeauregard, Calcasieu, Vernon6 hr
Nov 16, 6:02 PM CSTMesoscale DiscussionSPCArmstrong, Briscoe, Childress, Cottle, Crosby, Dickens and 12 more118 min
Nov 17, 1:11 AM CSTMesoscale DiscussionSPCClay, Hardeman, Hemphill, Lipscomb, Montague, Wheeler and 2 more3 hr
Nov 17, 7:11 AM CSTMesoscale DiscussionSPCAnderson, Angelina, Austin, Brazos, Burleson, Cherokee and 40 more3 hr
Nov 17, 7:43 AM CSTMesoscale DiscussionSPCCooke, Fannin, Grayson, Lamar, Montague3 hr
Nov 17, 8:15 AM CSTTornado WatchSPCArcher, Clay, Collin, Cooke, Dallas, Denton and 11 more5 hr
Nov 17, 9:58 AM CSTMesoscale DiscussionSPCBandera, Bexar, Blanco, Brown, Burnet, Callahan and 36 more92 min
Nov 17, 10:21 AM CSTMesoscale DiscussionSPCBrazoria, Calhoun, Chambers, Fort Bend, Hardin, Harris and 6 more84 min
Nov 17, 10:59 AM CSTMesoscale DiscussionSPCArcher, Clay, Collin, Cooke, Dallas, Denton and 11 more91 min
Nov 17, 11:50 AM CSTMesoscale DiscussionSPCAnderson, Angelina, Aransas, Austin, Bell, Bosque and 75 more85 min
Nov 17, 12:20 PM CSTTornado WatchSPCBell, Bosque, Collin, Comanche, Cooke, Coryell and 36 more6 hr
Nov 17, 3:02 PM CSTMesoscale DiscussionSPCAustin, Brazoria, Calhoun, Chambers, Colorado, DeWitt and 16 more88 min

Nearby

Mesoscale Discussions in Louisiana, 2003Mesoscale Discussions in Texas, 2003Every mesoscale discussion in 2003

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.