Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 111

February 21, 20036 parishes in Louisiana; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2003, 3:32 PM CST for 6 parishes in Louisiana; 6 counties in Texas. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: Feb 21, 2003, 3:32 PM CST (21:32 UTC)
Expired: Feb 21, 2003, 5:30 PM CST
In force: 118 min
Issued by: the Storm Prediction Center

Counties Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Vernon Parish, LA, Hardin County, TX, Jasper County, TX, Liberty County, TX, Newton County, TX, Orange County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 58 km from the middle of the area, began a volume at 21:33 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.

Tornado Watch 12Feb 21, 3:40 PM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 9.5 hours before the alert went out and 60 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: 543 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 433 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 253 m²/s²
0-3 km storm-relative helicity: 274 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.2

Open this sounding in Storm Lab

The text

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

809 
ACUS11 KWNS 212132
SWOMCD
SPC MCD 212132 
TXZ000-LAZ000-212330-

MESOSCALE DISCUSSION 0111
NWS STORM PREDICTION CENTER NORMAN OK
0332 PM CST FRI FEB 21 2003

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

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 212132Z - 212330Z

STRENGTHENING MID/UPPER FORCING FOR UPWARD VERTICAL MOTION
CONTINUES TO SUPPORT INCREASING CONVECTIVE DEVELOPMENT NEAR
DEEPENING SURFACE LOW...WHICH IS NOW MIGRATING NORTH/NORTHEAST OF
THE THE HOUSTON AREA.  ACTIVITY IS GRADUALLY EVOLVING INTO LARGER
MESOSCALE CONVECTIVE SYSTEM...WHICH WILL BE ACCOMPANIED BY
INCREASING DAMAGING WIND THREAT.  



GREATEST RISK OF DAMAGING WINDS IS EXPECTED NEAR APEX OF BOW ECHO
CONFIGURATION...WHICH IS LIKELY TO EVOLVE IN BAROCLINIC ZONE JUST
TO THE NORTH OF SURFACE WARM FRONT ACROSS THE JASPER TX/FORT POLK
LA BY 22/00-01Z. THREAT FOR ISOLATED TORNADIC SUPERCELLS WILL
ALSO PERSIST...MAINLY NEAR WARM FRONT JUST AHEAD OF BOW ECHO AND
SURFACE LOW...WHERE LOW-LEVEL SHEAR PROFILES ARE MOST FAVORABLE.



..KERR.. 02/21/2003

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

30959481 31249372 31369274 30779236 30399247 30079266
29939317 29939358 29919414 30019465 30139492

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 21, 1:43 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 6 more	2 hr
Feb 21, 4:35 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge, East Feliciana and 16 more	115 min
Feb 21, 9:02 AM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu, Cameron, Sabine, Vernon	58 min
Feb 21, 9:40 AM CST	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Caldwell, Cameron and 11 more	6 hr
Feb 21, 11:47 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 4 more	118 min
Feb 21, 3:40 PM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	6 hr
Feb 21, 5:20 PM CST	Mesoscale Discussion	SPC	Claiborne, East Carroll, Franklin, Jackson, Lincoln, Madison and 5 more	4 hr
Feb 21, 5:50 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	115 min
Feb 21, 2:43 AM CST	Mesoscale Discussion	SPC	Dimmit, Edwards, Frio, Kinney, La Salle, Maverick and 5 more	3 hr
Feb 21, 3:53 AM CST	Mesoscale Discussion	SPC	Aransas, Austin, Brazoria, Calhoun, Colorado, Fort Bend and 13 more	3 hr
Feb 21, 4:10 AM CST	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bastrop, Bexar, Blanco, Brazos and 26 more	6 hr
Feb 21, 4:25 AM CST	Tornado Watch	SPC	Austin, Brazoria, Brazos, Burleson, Calhoun, Colorado and 15 more	6 hr
Feb 21, 5:58 AM CST	Mesoscale Discussion	SPC	Atascosa, Bandera, Bastrop, Bexar, Blanco, Brazos and 26 more	2 hr
Feb 21, 6:16 AM CST	Mesoscale Discussion	SPC	Austin, Brazoria, Brazos, Burleson, Calhoun, Colorado and 17 more	119 min
Feb 21, 1:30 PM CST	Mesoscale Discussion	SPC	Hardin, Harris, Jasper, Liberty, Montgomery, Newton and 3 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2003 Mesoscale Discussions in Texas, 2003 Every 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; radar from the NEXRAD Level II archive.