Alert archive / Louisiana / Mesoscale Discussions in 2003
Mesoscale Discussion 430
The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2003, 9:42 AM CDT for 22 parishes in Louisiana; 4 counties in Texas. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 7, 2003, 9:42 AM CDT (14:42 UTC)
- Expired
- Apr 7, 2003, 12:15 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
All 26 counties
Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Saint James Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Chambers County, TX, Galveston County, TX, Jefferson County, TX, Orange County, TX
The radar
The Lake Charles radar (KLCH), 13 km from the middle of the area, began a volume at 14:44 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
Lake Charles Mun, LA (KLCH), launched 12:00Z, 2.7 hours before the alert went out and 12 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.
- Mixed-layer CAPE
- 1791 J/kg
- Mixed-layer CIN
- -58 J/kg
- Mixed-layer LCL
- 518 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- -64 m²/s²
- 0-3 km storm-relative helicity
- 9 m²/s²
- Significant tornado parameter
- -0.6
- Supercell composite
- -2.0
The text
As transmitted, in the capitals the NWS used until 2016.
554 ACUS11 KWNS 071443 SWOMCD SPC MCD 071442 LAZ000-TXZ000-071715- MESOSCALE DISCUSSION 0430 NWS STORM PREDICTION CENTER NORMAN OK 0942 AM CDT MON APR 07 2003 AREAS AFFECTED...S-CENTRAL/SWRN LA...EXTREME SERN TX CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 071442Z - 071715Z WIDELY SCATTERED TSTMS POSSIBLE PRIMARILY SE OF A LINE FROM GLS BAY REGION ENEWD TO 60 NW BTR...WITH ACTIVITY BOTH DEVELOPING OVER LAND AND MOVING NEWD OFF GULF. EXPECT COVERAGE/INTENSITY TO INCREASE STEADILY NEXT 2-3 HOURS. SUPERCELLS WITH LARGE HAIL AND DAMAGING GUSTS ARE POSSIBLE. SOME TORNADO POTENTIAL ALSO MAY DEVELOP WITH STORM-SCALE AND BOUNDARY INTERACTIONS. WW MAY BE REQUIRED WITHIN NEXT 1-2 HOURS. SURFACE MESOANALYSIS INDICATES PREFRONTAL CONFLUENCE LINE AND WEAK SFC TROUGH NEAR HOU-HEZ LINE...NEAR AND S OF WHICH MOST ACTIVITY AHOLD BE FOCUSED. MOISTURE CHANNEL IMAGERY AND RAOB ANALYSES INDICATE LOW-AMPLITUDE SHORTWAVE PERTURBATION NOW MOVING NEWD ACROSS TX COASTAL BEND REGION TOWARD DISCUSSION AREA. EXPECT INCREASING MID/UPPER LEVEL ASCENT/DESTABILIZATION ACROSS REGION AHEAD OF THIS FEATURE...ENHANCING LAPSE RATES ALOFT. 8-9 DEG C/KM MIDLEVEL LAPSE RATES SHOWN IN UPSTREAM CRP RAOB. EXPECT INCREASING CAPE IN TANDEM WITH SURFACE DIABATIC WARMING...WHICH SHOULD OVERCOME LOW LEVEL CINH EVIDENT IN MORNING RAOB DATA AND RUC SOUNDINGS. ONCE CONVECTION BECOMES NEARLY SURFACE BASED -- AS APPEARS TO BE OCCURRING WITH ACTIVITY OVER GULF AND AS SHOULD OCCUR OVER LAND BY ABOUT 16Z -- MLCAPE 1500-2500 J/KG IS POSSIBLE. VERTICAL SHEAR PROFILE APPEARS AT LEAST MARGINAL ON MESOSCALE WITH 40-50 KT 0-6 KM SHEAR AND BACKED LOW LEVEL FLOW ENHANCING SR SFC INFLOW. HOWEVER...LOW-MID LEVEL SR FLOW WEAKNESSES ABOVE SFC WILL LIMIT HODOGRAPH SIZE...KEEPING 0-3 KM SRH LARGELY IN 100-200 J/KG RANGE. ..EDWARDS.. 04/07/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LIX...LCH...HGX... 29109506 29719507 30619386 31039309 30949140 30289043 29359139
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 6, 8:13 PM CDT | Mesoscale Discussion | SPC | Catahoula, Concordia, Franklin, LaSalle, Tensas | 2 hr |
| Apr 7, 10:05 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 26 more | 6 hr |
| Apr 7, 11:02 AM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Cameron, East Baton Rouge, Iberville, Lafayette and 8 more | 3 hr |
| Apr 7, 2:13 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Calcasieu, Cameron, East Baton Rouge and 20 more | 3 hr |
| Apr 7, 2:36 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Calcasieu, Cameron, East Baton Rouge and 20 more | 114 min |
| Apr 7, 3:40 PM CDT | Severe Thunderstorm Watch | SPC | Acadia, Ascension, Assumption, Calcasieu, Cameron, East Baton Rouge and 22 more | 5 hr |
| Apr 7, 5:58 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Cameron, Iberia, Iberville, Lafayette and 10 more | 2 hr |
| Apr 7, 12:24 PM CDT | Mesoscale Discussion | SPC | Atascosa, Austin, Bastrop, Bee, Bexar, Brazoria and 28 more | 66 min |
| Apr 7, 1:00 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Austin, Bee, Bexar, Brazoria, Caldwell and 23 more | 5 hr |
| Apr 7, 3:36 PM CDT | Mesoscale Discussion | SPC | Edwards, Kinney, Maverick, Real, Uvalde, Val Verde | 114 min |
| Apr 7, 4:35 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bee, Bexar, Blanco, Caldwell and 22 more | 5 hr |
Nearby
Mesoscale Discussions in Louisiana, 2003Mesoscale Discussions in Texas, 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.