Alert archive / Louisiana / Mesoscale Discussions in 2004

Mesoscale Discussion 77

February 4, 200416 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Feb 4, 2004, 3:53 PM CST for 16 parishes in Louisiana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Feb 4, 2004, 3:53 PM CST (21:53 UTC)
Expired
Feb 4, 2004, 6:00 PM CST
In force
2 hr
Issued by
the Storm Prediction Center

Counties Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston 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

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 9.9 hours before the alert went out and 70 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, Lake Charles Mun, LA at 12:00Z on 2004-02-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Lake Charles Mun, LA at 12:00Z on 2004-02-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 335 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1862 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
335 m²/s²
0-3 km storm-relative helicity
442 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.

270 
ACUS11 KWNS 042153
SWOMCD
SPC MCD 042153 
LAZ000-TXZ000-050000-

MESOSCALE DISCUSSION 0077
NWS STORM PREDICTION CENTER NORMAN OK
0353 PM CST WED FEB 04 2004

AREAS AFFECTED...SRN LA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 042153Z - 050000Z

A MARGINAL HAIL THREAT WILL EXIST WITH THE MOST INTENSE TSTMS FOR
THE NEXT FEW HOURS. WW IS NOT ANTICIPATED.

OVER THE PAST HOUR OR SO...REGIONAL RADAR IMAGERY HAS INDICATED AN
INCREASE IN TSTM COVERAGE AND INTENSITY FROM S OF LCH TO 30SW OF
BTR. ISENTROPIC ASCENT ABOVE MARINE BOUNDARY APPROXIMATELY 50 MILES
OFF THE LA COAST...COUPLED WITH FORCING FOR ASCENT AHEAD OF WEAK
SHORTWAVE TROUGH TRANSLATING EWD THROUGH CNTRL LA...IS LIKELY
RESPONSIBLE FOR THIS INCREASE IN ACTIVITY. ALTHOUGH FORECAST
SOUNDINGS INDICATE ONLY A WEAKLY UNSTABLE ENVIRONMENT /I.E. MUCAPES
OF 300-600 J/KG/ ABOVE STABLE NEAR-SURFACE LAYER...FAVORABLY VEERING
WINDS THROUGH THE BUOYANCY LAYER MAY SUPPORT SOME MID-LEVEL ROTATION
WITH THE STRONGEST STORMS. ISOLATED...MARGINALLY SEVERE HAIL MAY
ACCOMPANY THE MOST INTENSE CELLS...HOWEVER THE WEAK INSTABILITY AND
RELATIVELY HIGH WBZ HEIGHTS OF AOA 10KFT SHOULD LIMIT THE OVERALL
HAIL THREAT.

..MEAD.. 02/04/2004

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

ATTN...WFO...LIX...LCH...

29749389 30139376 30509320 30659187 30469070 29659044
29289137 29379341

Nearby

Mesoscale Discussions in Louisiana, 2004Every mesoscale discussion in 2004

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.