Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 681

May 4, 200733 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at May 4, 2007, 11:35 AM CDT for 33 parishes in Louisiana. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 4, 2007, 11:35 AM CDT (16:35 UTC)
Expired: May 4, 2007, 1:00 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 33 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 4.6 hours before the alert went out and 251 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: 93 J/kg
Mixed-layer CIN: -157 J/kg
Mixed-layer LCL: 1036 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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, 1:40 AM CDT	Mesoscale Discussion	SPC	Assumption, Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard and 6 more	65 min
May 4, 7:40 AM CDT	Mesoscale Discussion	SPC	Ascension, Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana and 17 more	3 hr

Nearby

Mesoscale Discussions in Louisiana, 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.