Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 2126

October 22, 200920 parishes in Louisiana; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Oct 22, 2009, 3:36 PM CDT for 20 parishes in Louisiana; 8 counties in Mississippi. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Oct 22, 2009, 3:36 PM CDT (20:36 UTC)
Expired: Oct 22, 2009, 5:30 PM CDT
In force: 114 min
Issued by: the Storm Prediction Center

All 28 counties

Ascension Parish, LA, Assumption Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Richland Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint Martin Parish, LA, Tensas Parish, LA, Terrebonne Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Warren County, MS, Wilkinson County, MS

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 773Oct 22, 4:35 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.6 hours before the alert went out and 174 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: 6 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 917 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 123 m²/s²
0-3 km storm-relative helicity: 263 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Oct 22, 5:35 AM CDT	Mesoscale Discussion	SPC	Beauregard, Calcasieu, De Soto, Sabine, Vernon	85 min
Oct 22, 5:55 AM CDT	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Caldwell, Cameron and 12 more	6 hr
Oct 22, 7:48 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 19 more	117 min
Oct 22, 10:14 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 10 more	91 min
Oct 22, 11:27 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Caldwell, Catahoula, Concordia and 26 more	93 min
Oct 22, 11:58 AM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 40 more	7 hr
Oct 22, 4:35 PM CDT	Tornado Watch	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 5 more	4 hr
Oct 22, 6:26 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Carroll, East Feliciana, Livingston and 5 more	34 min
Oct 22, 6:55 PM CDT	Tornado Watch	SPC	Attala, Bolivar, Carroll, Copiah, Covington, Forrest and 22 more	3 hr

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Mississippi, 2009 Every mesoscale discussion in 2009

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.