Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 283

March 26, 200922 parishes in Louisiana; 12 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 26, 2009, 9:13 PM CDT for 22 parishes in Louisiana; 12 counties in Texas. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Mar 26, 2009, 9:13 PM CDT (02:13 UTC)
Expired
Mar 26, 2009, 10:45 PM CDT
In force
92 min
Issued by
the Storm Prediction Center
All 34 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Cherokee County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 2.2 hours before the alert went out and 189 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 2009-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 936 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 2009-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 square meters per square second.1939587897117Sfc1 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
936 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
949 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
219 m²/s²
Significant tornado parameter
0.9
Supercell composite
5.5

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 26, 11:53 PM CDTMesoscale DiscussionSPCAscension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 7 more97 min
Mar 27, 12:48 AM CDTTornado WatchSPCAscension, Assumption, Iberville, Jefferson, Lafourche, Livingston and 10 more7 hr
Mar 27, 2:23 AM CDTMesoscale DiscussionSPCAssumption, Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard and 3 more67 min
Mar 27, 4:37 AM CDTMesoscale DiscussionSPCJefferson, Lafourche, Plaquemines, Saint Bernard53 min
Mar 27, 6:35 AM CDTMesoscale DiscussionSPCJefferson, Plaquemines55 min
Mar 27, 12:33 PM CDTMesoscale DiscussionSPCBossier, Caddo57 min
Mar 27, 2:34 PM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Evangeline, Rapides, Saint Landry and 1 more56 min
Mar 27, 2:54 PM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, East Baton Rouge and 14 more6 hr
Mar 27, 4:16 PM CDTTornado WatchSPCCaldwell, Catahoula, Concordia, Franklin, Grant, LaSalle and 1 more4 hr
Mar 27, 4:49 PM CDTTornado WatchSPCCameron3 hr
Mar 27, 5:53 PM CDTMesoscale DiscussionSPCBienville, Bossier, Claiborne, East Carroll, Jackson, Lincoln and 7 more97 min
Mar 27, 6:18 PM CDTMesoscale DiscussionSPCLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington57 min
Mar 27, 6:35 PM CDTTornado WatchSPCBienville, Bossier, Caddo, Claiborne, De Soto, East Carroll and 13 more7 hr
Mar 26, 7:32 PM CDTSevere Thunderstorm WatchSPCCooke, Denton, Fannin, Grayson, Jack, Montague and 1 more4 hr
Mar 26, 11:34 PM CDTMesoscale DiscussionSPCDallam, Hartley, Moore, Oldham, Sherman4 hr
Mar 27, 2:55 AM CDTMesoscale DiscussionSPCArmstrong, Carson, Dallam, Deaf Smith, Hansford, Hartley and 9 more4 hr
Mar 27, 8:04 AM CDTMesoscale DiscussionSPCCollingsworth, Donley, Gray, Hemphill, Lipscomb, Ochiltree and 2 more4 hr
Mar 27, 10:24 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Austin, Bastrop, Bell, Brazoria and 43 more96 min
Mar 27, 11:48 AM CDTSevere Thunderstorm WatchSPCAustin, Brazos, Burleson, Chambers, Grimes, Hardin and 16 more5 hr
Mar 27, 12:30 PM CDTMesoscale DiscussionSPCCarson, Childress, Collingsworth, Donley, Gray, Hansford and 8 more6 hr
Mar 27, 12:58 PM CDTTornado WatchSPCAnderson, Angelina, Bowie, Camp, Cass, Cherokee and 28 more7 hr
Mar 27, 3:34 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Bowie, Camp, Cass, Cherokee and 28 more56 min
Mar 27, 3:43 PM CDTMesoscale DiscussionSPCChambers, Hardin, Harris, Jasper, Jefferson, Liberty and 6 more62 min

Nearby

Mesoscale Discussions in Louisiana, 2009Mesoscale Discussions in Texas, 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.