Alert archive / Louisiana / Mesoscale Discussions in 2004

Mesoscale Discussion 676

May 12, 2004Mobile County, Alabama; 7 parishes in Louisiana; Harrison County, Jackson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 12, 2004, 8:03 PM CDT for Mobile County, Alabama; 7 parishes in Louisiana; Harrison County, Jackson County, Mississippi. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
May 12, 2004, 8:03 PM CDT (01:03 UTC)
Expired
May 12, 2004, 9:00 PM CDT
In force
57 min
Issued by
the Storm Prediction Center

Counties Mobile County, AL, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA, Harrison County, MS, Jackson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 1.1 hours before the alert went out and 43 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, Slidell Radar S, LA at 00:00Z on 2004-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 85 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, Slidell Radar S, LA at 00:00Z on 2004-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 square meters per square second.1939Sfc1 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
85 J/kg
Mixed-layer CIN
-101 J/kg
Mixed-layer LCL
694 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
104 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

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
May 13, 12:10 PM CDTTornado WatchSPCAllen, Beauregard, Calcasieu6 hr
May 13, 1:38 PM CDTMesoscale DiscussionSPCBeauregard, Calcasieu, Sabine97 min
May 13, 2:55 PM CDTTornado WatchSPCAcadia, Allen, Assumption, Avoyelles, Bienville, Bossier and 31 more6 hr
May 13, 3:54 PM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Avoyelles, Bienville, Caldwell and 29 more2 hr
May 13, 5:22 PM CDTMesoscale DiscussionSPCCalcasieu53 min
May 13, 6:23 PM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Avoyelles, Bienville, Caldwell and 30 more97 min

Nearby

Mesoscale Discussions in Louisiana, 2004Mesoscale Discussions in Mississippi, 2004Mesoscale Discussions in Alabama, 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.