Alert archive / Louisiana / Mesoscale Discussions in 2005

Mesoscale Discussion 554

April 11, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2005, 9:41 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 11, 2005, 9:41 AM CDT (14:41 UTC)
Expired: Apr 11, 2005, 11:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 95 counties

Ashley County, AR, Bradley County, AR, Chicot County, AR, Columbia County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Terrebonne Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Montgomery County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS, Chambers County, TX, Galveston County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX

The watches that followed

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

Tornado Watch 150Apr 11, 10:15 AM CDT

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 2.7 hours before the alert went out and 153 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1084 J/kg
Mixed-layer CIN: -143 J/kg
Mixed-layer LCL: 737 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 285 m²/s²
0-3 km storm-relative helicity: 342 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 12.2

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 111442
SWOMCD
SPC MCD 111441 
MSZ000-LAZ000-ARZ000-TXZ000-111645-

MESOSCALE DISCUSSION 0554
NWS STORM PREDICTION CENTER NORMAN OK
0941 AM CDT MON APR 11 2005

AREAS AFFECTED...SE TX...LA...WRN MS

CONCERNING...SEVERE THUNDERSTORM WATCH 149...

VALID 111441Z - 111645Z

A TORNADO WATCH WILL REPLACE WW 149 SHORTLY THAT WILL COVER SERN TX
NEWD INTO A SMALL PART OF W CENTAL MS. PROBABILITIES WILL BE RAISED
FOR A HIGH RISK FOR PARTS OF NERN LA INTO CENTRAL MS.

SQUALL LINE CURRENTLY EXTENDS FROM E CENTRAL TX SWWD W OF THE HOU
AREA.  ALSO...A WARM FRONT EXTENDS FROM S OF MLU EWD NE OF
HEZ...THEN CONTINUES SEWD TOWARDS MOB. VISIBLE SATELLITE IMAGERY
SHOWS CLEAR AREA ACROSS MUCH OF SERN LA INTO CENTRAL MS INDICATING
AREA OF BEST HEATING/DESTABILIZATION FOR THIS AFTERNOON.  KLCH RAOB
DATA SHOWS FAVORABLE SHEAR PROFILE OF 50 KT IN THE 0-6KM LAYER AND
BRN SHEAR VALUES OF 87 M2/S2.  LOW LEVEL JET OF 40-45 KT EXTENDS
NNEWD FROM S CENTRAL LA INTO WRN MS UNDERNEATH STRONG UPPER LEVEL
DIVERGENCE AS SRN BRANCH JET MAX OF 80-90 KT EXTENDS ACROSS SRN TX
PLACING AREA IN FAVORABLE EXIT REGION LATER THIS MORNING INTO SRN
LA.

THIS SETS UP FAVORABLE PROFILE FOR SUPERCELL STORMS/ISOLATED
TORNADOES AHEAD OF THE MAIN SQUALL LINE NEAR AND SOUTH OF THE WARM
FRONTAL BOUNDARY.  CURRENTLY...MUCAPE OF 2000 J/KG ALSO EXISTS
ACROSS THE AREA WITH LOW-MID LEVEL LAPSE RATES OF 7C/KM SUPPORTING
DEEP CONVECTION WITH LARGE HAIL.  THIS AREA IS SETTING UP TO BE AN
AREA THAT NEEDS TO BE MONITORED CLOSELY THROUGH THIS AFTERNOON INTO
THIS EVENING.

..MCCARTHY.. 04/11/2005

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

ATTN...WFO...MEG...JAN...LIX...LZK...LCH...SHV...HGX...

28889560 29819488 30649437 31379397 32149359 33329329
33549179 33749064 33688949 32658935 31349002 30659013
29829043 29319066 29059105

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 10, 8:53 PM CDT	Mesoscale Discussion	SPC	Benton, Crawford, Sebastian, Washington	2 hr
Apr 10, 9:15 PM CDT	Severe Thunderstorm Watch	SPC	Benton, Carroll, Clark, Crawford, Franklin, Howard and 10 more	7 hr
Apr 11, 1:23 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Clark, Crawford, Franklin, Howard and 11 more	67 min
Apr 11, 3:12 AM CDT	Mesoscale Discussion	SPC	Columbia, Lafayette, Miller, Union	63 min
Apr 11, 3:23 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Clark, Crawford, Franklin, Howard and 11 more	67 min
Apr 11, 3:45 AM CDT	Severe Thunderstorm Watch	SPC	Ashley, Bradley, Columbia, Lafayette, Miller, Union	7 hr
Apr 11, 6:17 AM CDT	Mesoscale Discussion	SPC	Arkansas, Clay, Cleburne, Conway, Craighead, Crittenden and 27 more	118 min
Apr 11, 6:53 AM CDT	Mesoscale Discussion	SPC	Ashley, Columbia, Lafayette, Miller, Union	67 min
Apr 11, 10:15 AM CDT	Tornado Watch	SPC	Ashley, Chicot, Desha, Drew	9 hr
Apr 11, 12:12 PM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Chicot, Columbia, Union	2 hr
Apr 11, 2:01 PM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Madison, Washington	89 min
Apr 11, 3:56 AM CDT	Mesoscale Discussion	SPC	Franklin, Madison, Tensas	64 min
Apr 11, 1:41 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Lafourche and 14 more	2 hr
Apr 11, 2:05 PM CDT	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 14 more	7 hr
Apr 11, 6:35 PM CDT	Tornado Watch	SPC	Jefferson, Lafourche, Orleans, Saint Bernard, Saint Charles, Saint Tammany and 1 more	4 hr
Apr 11, 6:52 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 9 more	83 min
Apr 11, 1:17 PM CDT	Mesoscale Discussion	SPC	Alcorn, Benton, Coahoma, Itawamba, Lafayette, Lee and 10 more	58 min
Apr 11, 1:35 PM CDT	Tornado Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 10 more	5 hr
Apr 10, 7:39 PM CDT	Mesoscale Discussion	SPC	Bandera, Bastrop, Bell, Bexar, Blanco, Bosque and 45 more	96 min
Apr 10, 10:45 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Bastrop, Bell, Bexar, Blanco, Brazos and 39 more	6 hr

Nearby

Mesoscale Discussions in Louisiana, 2005 Mesoscale Discussions in Mississippi, 2005 Mesoscale Discussions in Texas, 2005 Every mesoscale discussion in 2005

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.