Alert archive / Louisiana / Mesoscale Discussions in 2013

Mesoscale Discussion 555

April 24, 20137 parishes in Louisiana; 4 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2013, 11:48 AM CDT for 7 parishes in Louisiana; 4 counties in Mississippi. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Apr 24, 2013, 11:48 AM CDT (16:48 UTC)
Expired
Apr 24, 2013, 12:45 PM CDT
In force
57 min
Issued by
the Storm Prediction Center

Counties Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Tammany Parish, LA, Hancock County, MS, Harrison County, MS, Pearl River County, MS, Stone County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.8 hours before the alert went out and 53 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 12:00Z on 2013-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 789 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 12:00Z on 2013-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 square meters per square second.1939587897Sfc1 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
789 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
481 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
265 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.7

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, 4:51 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 3 more54 min
Apr 24, 6:38 AM CDTTornado WatchSPCAcadia, Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana and 25 more8 hr
Apr 24, 9:00 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, Iberia, Iberville, Jefferson and 16 more90 min

Nearby

Mesoscale Discussions in Louisiana, 2013Mesoscale Discussions in Mississippi, 2013Every mesoscale discussion in 2013

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.