Alert archive / Louisiana / Mesoscale Discussions in 2004

Mesoscale Discussion 466

April 24, 200417 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2004, 11:38 AM CDT for 17 parishes in Louisiana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 24, 2004, 11:38 AM CDT (16:38 UTC)
Expired
Apr 24, 2004, 1:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA

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, 4.6 hours before the alert went out and 208 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 12:00Z on 2004-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 410 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 12:00Z on 2004-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 square meters per square second.193958Sfc1 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
410 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
816 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
168 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 24, 12:35 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Bienville and 35 more6 hr
Apr 24, 3:09 PM CDTMesoscale DiscussionSPCAvoyelles, Catahoula, Concordia, Franklin, Iberia, Lafayette and 9 more66 min
Apr 24, 5:04 PM CDTMesoscale DiscussionSPCAscension, Assumption, Concordia, East Baton Rouge, East Carroll, East Feliciana and 13 more26 min

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.