Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 2279

December 24, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Dec 24, 2009, 3:30 AM CST for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Dec 24, 2009, 3:30 AM CST (09:30 UTC)
Expired
Dec 24, 2009, 5:30 AM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 100 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tensas Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Warren County, MS, Wilkinson County, MS, Angelina County, TX, Bowie County, TX, Brazoria County, TX, Camp County, TX, Cass County, TX, Chambers County, TX, Cherokee County, TX, Fort Bend County, TX, Galveston County, TX, Gregg County, TX, Hardin County, TX, Harris County, TX, Harrison County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Marion County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX, Walker County, TX

The radar

The Lake Charles radar (KLCH), 18 km from the middle of the area, began a volume at 09:32 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.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 9.5 hours before the alert went out and 20 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, Lake Charles Mun, LA at 00:00Z on 2009-12-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1390 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, Lake Charles Mun, LA at 00:00Z on 2009-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 183 square meters per square second.19395878Sfc1 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
1390 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
475 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
183 m²/s²
0-3 km storm-relative helicity
158 m²/s²
Significant tornado parameter
1.2
Supercell composite
6.0

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.

IssuedProductOfficeCountiesLasted
Dec 23, 7:50 PM CSTMesoscale DiscussionSPCClark, Columbia, Hempstead, Howard, Lafayette, Little River and 7 more85 min
Dec 23, 8:48 PM CSTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 1 more9 hr
Dec 23, 11:06 PM CSTMesoscale DiscussionSPCClark, Columbia, Dallas, Hempstead, Hot Spring, Howard and 7 more114 min
Dec 24, 4:50 AM CSTTornado WatchSPCAshley, Chicot, Union7 hr
Dec 24, 7:30 AM CSTMesoscale DiscussionSPCAshley90 min
Dec 24, 10:13 AM CSTMesoscale DiscussionSPCAshley, Chicot, Union62 min
Dec 24, 9:34 AM CSTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more56 min
Dec 24, 10:37 AM CSTTornado WatchSPCJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles, Saint Tammany and 2 more7 hr
Dec 24, 1:14 PM CSTMesoscale DiscussionSPCJefferson, Orleans, Plaquemines, Saint Bernard, Saint Tammany, Washington61 min
Dec 24, 3:33 PM CSTMesoscale DiscussionSPCClarke, Forrest, George, Greene, Harrison, Jackson and 11 more57 min
Dec 23, 11:43 PM CSTMesoscale DiscussionSPCArcher, Baylor, Childress, Cottle, Dickens, Foard and 9 more6 hr
Dec 24, 7:25 AM CSTMesoscale DiscussionSPCArcher, Baylor, Callahan, Childress, Clay, Collingsworth and 23 more6 hr
Dec 24, 11:23 AM CSTMesoscale DiscussionSPCCollin, Delta, Denton, Fannin, Grayson, Hopkins and 3 more6 hr

Nearby

Mesoscale Discussions in Louisiana, 2009Mesoscale Discussions in Texas, 2009Mesoscale Discussions in Mississippi, 2009Every 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.