Alert archive / Texas / Mesoscale Discussions in 2003

Mesoscale Discussion 554

April 24, 20035 counties in Arkansas; 6 parishes in Louisiana; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2003, 2:41 AM CDT for 5 counties in Arkansas; 6 parishes in Louisiana; 18 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 24, 2003, 2:41 AM CDT (07:41 UTC)
Expired
Apr 24, 2003, 4:45 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 29 counties

Columbia County, AR, Lafayette County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Webster Parish, LA, Anderson County, TX, Bell County, TX, Cass County, TX, Cherokee County, TX, Falls County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Leon County, TX, Limestone County, TX, Marion County, TX, Panola County, TX, Robertson County, TX, Rusk County, TX, Smith County, TX, Upshur County, TX, Williamson County, TX

The radar

The Shreveport radar (KSHV), 142 km from the middle of the area, began a volume at 07:42 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.

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 7.7 hours before the alert went out and 151 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 2003-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 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 2003-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 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
35 J/kg
Mixed-layer CIN
-289 J/kg
Mixed-layer LCL
1142 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
230 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

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

996 
ACUS11 KWNS 240742
SWOMCD
SPC MCD 240741 
LAZ000-ARZ000-TXZ000-240945-

MESOSCALE DISCUSSION 0554
NWS STORM PREDICTION CENTER NORMAN OK
0241 AM CDT THU APR 24 2003

AREAS AFFECTED...NERN TX...NRN LA...SRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 153...

VALID 240741Z - 240945Z

...SEVERE THUNDERSTORM WATCH WILL BE ALLOWED TO EXPIRE AS
SCHEDULED...

THUNDERSTORMS HAVE DECREASED IN INTENSITY AS THEY LIFT NEWD ACROSS
ERN PORTIONS OF WW EARLY THIS MORNING.	RECENT TRENDS HOWEVER
INDICATE GRADUAL MOISTENING OBSERVED AT MID LEVELS...MOST LIKELY A
RESULT OF ASCENT BENEATH REGION OF LARGE SCALE UPPER DIFFLUENCE. 
WITHIN THIS ZONE...A NARROW LINE OF THUNDERSTORMS IS SLOWLY
INCREASING FROM SWRN PORTIONS OF WW...SWWD INTO CENTRAL TX SOUTHEAST
OF ACT.  THIS ACTIVITY MAY CONTINUE TO DEVELOP AND SPREAD NEWD
ACROSS ECNTRL TX INTO NRN LA.  THERE IS SOME QUESTION WHETHER THIS
APPARENTLY ELEVATED CONVECTION WILL ATTAIN ORGANIZED SEVERE LEVELS
DUE TO LINEAR STRUCTURE AND ORIENTATION TO MEAN WIND.  WW WILL BE
ALLOWED TO EXPIRE AS SCHEDULED.

..DARROW.. 04/24/2003

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

ATTN...WFO...LZK...SHV...HGX...FWD...EWX...

31199770 32639512 33689355 33729265 32439272 30509782

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 23, 11:43 PM CDTMesoscale DiscussionSPCHoward, Lafayette, Little River, Miller, Polk, Sevier2 hr
Apr 24, 10:12 AM CDTMesoscale DiscussionSPCArkansas, Cleburne, Conway, Craighead, Crittenden, Cross and 20 more2 hr
Apr 24, 12:47 PM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 38 more3 hr
Apr 24, 1:00 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 25 more7 hr
Apr 24, 2:05 PM CDTTornado WatchSPCAshley, Chicot6 hr
Apr 24, 2:46 PM CDTMesoscale DiscussionSPCChicot119 min
Apr 24, 3:25 PM CDTTornado WatchSPCBaxter, Boone, Cleburne, Conway, Faulkner, Fulton and 19 more5 hr
Apr 24, 3:28 PM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Cleveland, Conway, Craighead and 32 more2 hr
Apr 24, 5:52 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Boone, Clay, Cleburne, Cleveland and 36 more113 min
Apr 24, 6:35 PM CDTTornado WatchSPCArkansas, Baxter, Clay, Cleburne, Cleveland, Conway and 33 more5 hr
Apr 24, 6:49 PM CDTMesoscale DiscussionSPCChicot56 min
Apr 24, 6:30 AM CDTSevere Thunderstorm WatchSPCAvoyelles, Beauregard, Bienville, Caldwell, Catahoula, Concordia and 17 more5 hr
Apr 24, 6:40 AM CDTSevere Thunderstorm WatchSPCAvoyelles, Beauregard, Bienville, Caldwell, Catahoula, Concordia and 17 more4 hr
Apr 24, 9:39 AM CDTMesoscale DiscussionSPCCaldwell, Catahoula, Concordia, Grant, LaSalle, Tensas and 1 more2 hr
Apr 24, 11:40 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Catahoula, Concordia and 10 more65 min
Apr 24, 5:17 PM CDTMesoscale DiscussionSPCOrleans, Saint Tammany, Washington118 min
Apr 23, 7:00 PM CDTMesoscale DiscussionSPCCrockett, Edwards, Kimble, Kinney, Mason, Menard and 5 more90 min
Apr 23, 7:03 PM CDTMesoscale DiscussionSPCBosque, Collin, Comanche, Cooke, Coryell, Dallas and 25 more117 min
Apr 23, 7:45 PM CDTTornado WatchSPCBandera, Bexar, Blanco, Burnet, Caldwell, Comal and 11 more4 hr
Apr 23, 8:43 PM CDTMesoscale DiscussionSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 15 more77 min
Apr 23, 9:35 PM CDTSevere Thunderstorm WatchSPCCollin, Cooke, Dallas, Delta, Denton, Ellis and 20 more5 hr
Apr 24, 7:14 AM CDTMesoscale DiscussionSPCAustin, Bastrop, Brazoria, Brazos, Burleson, Caldwell and 22 more2 hr
Apr 24, 7:30 AM CDTTornado WatchSPCAngelina, Austin, Brazoria, Brazos, Burleson, Chambers and 17 more6 hr
Apr 24, 9:11 AM CDTMesoscale DiscussionSPCFort Bend, Harris, Liberty, Montgomery, Polk, San Jacinto2 hr

Nearby

Mesoscale Discussions in Texas, 2003Mesoscale Discussions in Louisiana, 2003Mesoscale Discussions in Arkansas, 2003Every 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.