Alert archive / Louisiana / Mesoscale Discussions in 2004

Mesoscale Discussion 2449

November 23, 200413 parishes in Louisiana; 11 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Nov 23, 2004, 9:14 PM CST for 13 parishes in Louisiana; 11 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Nov 23, 2004, 9:14 PM CST (03:14 UTC)
Expired
Nov 23, 2004, 11:15 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 24 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Madison Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, West Feliciana Parish, LA, Adams County, MS, Claiborne County, MS, Franklin County, MS, Hinds County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Warren County, MS, Wilkinson County, MS, Yazoo County, MS

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 3.2 hours before the alert went out and 156 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, Jackson, MS at 00:00Z on 2004-11-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1370 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, Jackson, MS at 00:00Z on 2004-11-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 185 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
1370 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
857 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
185 m²/s²
0-3 km storm-relative helicity
198 m²/s²
Significant tornado parameter
1.9
Supercell composite
6.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

526 
ACUS11 KWNS 240314
SWOMCD
SPC MCD 240314 
MSZ000-LAZ000-240515-

MESOSCALE DISCUSSION 2449
NWS STORM PREDICTION CENTER NORMAN OK
0914 PM CST TUE NOV 23 2004

AREAS AFFECTED...CNTRL/NRN LA INTO WRN/CNTRL AND NRN MS

CONCERNING...TORNADO WATCH 888...890...

VALID 240314Z - 240515Z

CONTINUE WWS.

LOW-LEVEL CONFLUENT ZONE ALONG/JUST EAST OF SOUTHERLY LOW-LEVEL JET
STRENGTHENING TO NEAR 50 KT LATE THIS EVENING REMAINS FOCUS FOR
INTENSE CONVECTIVE DEVELOPMENT...INCLUDING ISOLATED SUPERCELLS. 
THIS BAND EXTENDS FROM NEAR ALEXANDRIA LA THROUGH THE VICINITY OF
VICKSBURG MS INTO AREAS SOUTH OF GREENWOOD...WHERE BOUNDARY LAYER
DEW POINTS NEAR 70F ARE CONTRIBUTING TO NARROW TONGUE OF MEAN MIXED
LAYER CAPE UP TO AROUND 1000 J/KG.  GIVEN MOIST AND BUOYANT BOUNDARY
LAYER...STRONG LOW-LEVEL SHEAR PROFILES AND STRENGTHENING FLOW ALOFT
WILL CONTINUE TO PROVIDE FAVORABLE ENVIRONMENT FOR TORNADIC
SUPERCELLS INTO THE OVERNIGHT HOURS.

..KERR.. 11/24/2004

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LIX...LCH...SHV...

31079280 31649202 32509143 33259084 33379030 32848996
31969065 31219093 30729160 30249239 30429303

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 23, 7:50 PM CSTTornado WatchSPCSabine6 hr
Nov 23, 7:53 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 20 more37 min
Nov 23, 8:15 PM CSTTornado WatchSPCAllen, Avoyelles, Beauregard, Caldwell, Catahoula, Concordia and 21 more6 hr
Nov 23, 10:01 PM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 38 more119 min
Nov 23, 11:00 PM CSTSevere Thunderstorm WatchSPCAcadia, Ascension, Assumption, Calcasieu, Cameron, Iberia and 15 more7 hr
Nov 24, 12:30 AM CSTMesoscale DiscussionSPCSaint Tammany, Tangipahoa, Washington30 min
Nov 24, 12:45 AM CSTTornado WatchSPCSaint Helena, Tangipahoa, Washington5 hr
Nov 24, 1:28 AM CSTMesoscale DiscussionSPCAvoyelles, Concordia, East Baton Rouge, East Carroll, East Feliciana, Evangeline and 9 more32 min
Nov 24, 1:45 AM CSTTornado WatchSPCEast Baton Rouge, East Feliciana, Livingston, Pointe Coupee, Saint Helena, Saint Landry and 2 more4 hr
Nov 24, 2:43 AM CSTMesoscale DiscussionSPCTangipahoa, Washington62 min
Nov 24, 2:50 AM CSTTornado WatchSPCAscension, Assumption, East Baton Rouge, Iberville, Jefferson, Lafourche and 11 more3 hr
Nov 24, 5:35 AM CSTMesoscale DiscussionSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard25 min
Nov 24, 5:55 AM CSTTornado WatchSPCPlaquemines, Saint Bernard2 hr
Nov 23, 6:35 PM CSTTornado WatchSPCAlcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 28 more7 hr
Nov 23, 9:00 PM CSTMesoscale DiscussionSPCAlcorn, Itawamba, Prentiss, Tishomingo2 hr
Nov 23, 9:20 PM CSTTornado WatchSPCItawamba, Lowndes, Monroe, Tishomingo7 hr
Nov 24, 3:35 AM CSTMesoscale DiscussionSPCLowndes25 min
Nov 24, 4:57 AM CSTMesoscale DiscussionSPCClarke, Forrest, George, Greene, Lamar, Pearl River and 3 more63 min
Nov 24, 5:20 AM CSTTornado WatchSPCGeorge, Jackson6 hr
Nov 24, 10:16 AM CSTMesoscale DiscussionSPCAlcorn, Benton, Lafayette, Marshall, Prentiss, Tippah and 1 more2 hr

Nearby

Mesoscale Discussions in Louisiana, 2004Mesoscale Discussions in Mississippi, 2004Every mesoscale discussion in 2004

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.