Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 404

April 6, 20039 counties in Arkansas; 22 parishes in Louisiana; 11 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2003, 7:38 AM CDT for 9 counties in Arkansas; 22 parishes in Louisiana; 11 counties in Mississippi. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Apr 6, 2003, 7:38 AM CDT (12:38 UTC)
Expired: Apr 6, 2003, 9:15 AM CDT
In force: 97 min
Issued by: the Storm Prediction Center

All 42 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Columbia County, AR, Lafayette County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Issaquena County, MS, Jefferson County, MS, Lincoln County, MS, Sharkey County, MS, Warren 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

Shreveport, LA (KSHV), launched 12:00Z, 0.6 hours before the alert went out and 163 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: 1292 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 492 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 259 m²/s²
0-3 km storm-relative helicity: 405 m²/s²
Significant tornado parameter: 2.5
Supercell composite: 20.3

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 061239
SWOMCD
SPC MCD 061238 
MSZ000-LAZ000-ARZ000-TXZ000-061415-

MESOSCALE DISCUSSION 0404
NWS STORM PREDICTION CENTER NORMAN OK
0738 AM CDT SUN APR 06 2003

AREAS AFFECTED...NRN LA...SRN AR

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 061238Z - 061415Z

THUNDERSTORMS WILL INCREASE IN INTENSITY AND COVERAGE THROUGHOUT
THE DAY.  A WW WILL LIKELY BE REQUIRED.



ELEVATED THUNDERSTORMS HAVE FORMED OVER NRN LA...JUST N OF A WARM
FRONT EXTENDING FROM NERN TX SEWD INTO CENTRAL MS.  12Z SHV
SOUNDING SHOWS MDT INSTABILITY WITH SHEAR PROFILES SUPPORTIVE OF
SUPERCELLS.  INITIALLY...THE MAIN SEVERE THREAT WILL BE LARGE
HAIL GIVEN COOL TEMPERATURES ALOFT AND A STABLE BOUNDARY LAYER. 
HOWEVER...SEVERE THREAT WILL EVOLVE DURING THE AFTERNOON AS LOW
LEVELS BECOME UNSTABLE ALONG AND SOUTH OF THIS
BOUNDARY...INCREASING THE TORNADO THREAT.

..JEWELL.. 04/06/2003

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

ATTN...WFO...JAN...LIX...LZK...SHV...

31489213 32069332 32509414 33819346 33599177 32759029
31719011 31179109 31379200

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 6, 7:50 AM CDT	Severe Thunderstorm Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Drew and 6 more	5 hr
Apr 6, 8:56 AM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Cleburne, Conway and 21 more	2 hr
Apr 6, 9:45 AM CDT	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Carroll, Conway, Crawford and 22 more	5 hr
Apr 6, 10:00 AM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Chicot, Desha, Drew, Jefferson and 4 more	2 hr
Apr 6, 10:20 AM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 21 more	55 min
Apr 6, 10:30 AM CDT	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Drew and 6 more	6 hr
Apr 6, 11:05 AM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Baxter, Cleburne, Cleveland, Craighead, Crittenden and 27 more	5 hr
Apr 6, 12:27 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleburne, Cleveland, Conway, Craighead and 46 more	2 hr
Apr 6, 2:18 PM CDT	Mesoscale Discussion	SPC	Boone, Conway, Crawford, Franklin, Garland, Howard and 16 more	57 min
Apr 6, 2:55 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Boone, Clark, Cleburne, Conway, Crawford and 35 more	5 hr
Apr 6, 3:45 PM CDT	Tornado Watch	SPC	Ashley, Chicot, Union	5 hr
Apr 6, 5:35 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot, Union	115 min
Apr 6, 6:23 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot, Union	97 min
Apr 6, 12:03 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 14 more	117 min
Apr 6, 3:26 PM CDT	Mesoscale Discussion	SPC	Bienville, Caldwell, De Soto, Franklin, Grant, Jackson and 11 more	2 hr
Apr 6, 6:50 PM CDT	Tornado Watch	SPC	Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Evangeline and 11 more	6 hr
Apr 6, 12:40 PM CDT	Mesoscale Discussion	SPC	Attala, Choctaw, Holmes, Kemper, Lauderdale, Leake and 9 more	2 hr
Apr 6, 1:35 PM CDT	Tornado Watch	SPC	Choctaw, Clarke, Jasper, Jones, Kemper, Lauderdale and 7 more	5 hr
Apr 6, 2:56 PM CDT	Mesoscale Discussion	SPC	Kemper, Lauderdale, Leake, Neshoba, Newton, Noxubee and 2 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2003 Mesoscale Discussions in Mississippi, 2003 Mesoscale Discussions in Arkansas, 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.