Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 2124

October 22, 200916 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Oct 22, 2009, 10:14 AM CDT for 16 parishes in Louisiana. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Oct 22, 2009, 10:14 AM CDT (15:14 UTC)
Expired: Oct 22, 2009, 11:45 AM CDT
In force: 91 min
Issued by: the Storm Prediction Center

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA

The radar

The Lake Charles radar (KLCH), 55 km from the middle of the area, began a volume at 15:17 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

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

Tornado Watch 772Oct 22, 12:00 PM CDT

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 3.2 hours before the alert went out and 55 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: 833 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 773 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 182 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 5.9

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, 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, 3:36 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Carroll and 14 more	114 min
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

Nearby

Mesoscale Discussions in Louisiana, 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; radar from the NEXRAD Level II archive.