Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 679

May 4, 200712 parishes in Louisiana; 7 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 4, 2007, 1:40 AM CDT for 12 parishes in Louisiana; 7 counties in Mississippi. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: May 4, 2007, 1:40 AM CDT (06:40 UTC)
Expired: May 4, 2007, 2:45 AM CDT
In force: 65 min
Issued by: the Storm Prediction Center

Counties Assumption Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, Covington County, MS, Forrest County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 6.7 hours before the alert went out and 19 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1123 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 979 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.6

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.

Issued	Product	Office	Counties	Lasted
May 3, 8:50 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 31 more	85 min
May 3, 9:44 PM CDT	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 21 more	6 hr
May 3, 11:37 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 18 more	83 min
May 4, 7:40 AM CDT	Mesoscale Discussion	SPC	Ascension, Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana and 17 more	3 hr
May 4, 11:35 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, East Baton Rouge and 27 more	85 min
May 3, 7:55 PM CDT	Mesoscale Discussion	SPC	Bolivar, Carroll, Coahoma, Grenada, Humphreys, Issaquena and 11 more	95 min

Nearby

Mesoscale Discussions in Louisiana, 2007 Mesoscale Discussions in Mississippi, 2007 Every mesoscale discussion in 2007

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.