Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 376

April 4, 2003Ashley County, Chicot County, Arkansas; 23 parishes in Louisiana; Issaquena County, Sharkey County, Washington County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2003, 2:58 PM CST for Ashley County, Chicot County, Arkansas; 23 parishes in Louisiana; Issaquena County, Sharkey County, Washington County, Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 4, 2003, 2:58 PM CST (20:58 UTC)
Expired: Apr 4, 2003, 5:00 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center

All 28 counties

Ashley County, AR, Chicot County, AR, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Issaquena County, MS, Sharkey County, MS, Washington County, MS

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 9.0 hours before the alert went out and 138 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: 222 J/kg
Mixed-layer CIN: -308 J/kg
Mixed-layer LCL: 565 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 269 m²/s²
0-3 km storm-relative helicity: 221 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

815 
ACUS11 KWNS 042058
SWOMCD
SPC MCD 042058 
MSZ000-ARZ000-LAZ000-042300-

MESOSCALE DISCUSSION 0376
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CST FRI APR 04 2003

AREAS AFFECTED...ECNTRL TX AND CNTRL/NRN LA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 042058Z - 042300Z

TSTMS HAVE SLOWLY INTENSIFIED JUST WEST OF THE SABINE RIVER
ACROSS ECNTRL TX DURING THE PAST HOUR.	ACTIVITY APPEARS TO BE
TIED WITH UPPER DIFFLUENT REGION BETWEEN SUBTROPICAL JET AND
MIDLEVEL JETLET MIGRATING TOWARD THE MID MS VLY.  THE MAJORITY OF
MASS CONVERGENCE CONTINUES TO BE AIMED FAR NORTH OF THE
REGION...BUT SUFFICIENT UPPER SUPPORT EXISTS TO AID IN TSTM
DEVELOPMENT.  AIR MASS HAS DESTABILIZED WITH MLCAPES OF AROUND
1000 J/KG.  GIVEN STEEP MIDLEVEL LAPSE RATES AND FAVORABLE DEEP
LAYER SHEAR...ORGANIZED SEVERE TSTMS WITH LARGE HAIL AND DAMAGING
WINDS ARE POSSIBLE.  VWP FROM SHV SUGGESTS THAT THE LOW LEVEL
FLOW HAS INCREASED AND BACK...WITH SRH INCREASING.  THUS...ISOLD
TORNADOES ARE ALSO POSSIBLE...ESPECIALLY GIVEN LOW LCLS. TSTMS
ARE APT TO DEVELOP NEWD TOWARD THE ARKLAMISS REGION LATER THIS
EVENING.  IF ACTIVITY CONTINUES TO INCREASE...A WW MAY BE
REQUIRED.

..RACY.. 04/04/2003

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

ATTN...WFO...JAN...LZK...LCH...SHV...

32159380 33039263 33739095 33119061 31819135 31279194
30949331

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 4, 4:43 PM CST	Mesoscale Discussion	SPC	Arkansas, Calhoun, Clark, Clay, Cleburne, Cleveland and 36 more	3 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.