Alert archive / Mississippi / Mesoscale Discussions in 2014

Mesoscale Discussion 1983

December 23, 20144 counties in Alabama; 35 parishes in Louisiana; 46 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Dec 23, 2014, 7:39 AM CST for 4 counties in Alabama; 35 parishes in Louisiana; 46 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Dec 23, 2014, 7:39 AM CST (13:39 UTC)
Expired: Dec 23, 2014, 10:15 AM CST
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 85 counties

Choctaw County, AL, Greene County, AL, Pickens County, AL, Sumter County, AL, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Cameron Parish, LA, Concordia 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, Pointe Coupee Parish, LA, Saint Bernard 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, Tensas Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Hinds County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Warren County, MS, Wayne County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS

The watches that followed

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

Tornado Watch 560Dec 23, 9:30 AM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 1.7 hours before the alert went out and 120 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: 1212 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 831 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 75 m²/s²
0-3 km storm-relative helicity: 190 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.1

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
Dec 23, 3:45 AM CST	Mesoscale Discussion	SPC	Baldwin	2 hr
Dec 23, 7:40 AM CST	Mesoscale Discussion	SPC	Baldwin, Butler, Clarke, Coffee, Conecuh, Covington and 8 more	2 hr
Dec 23, 9:30 AM CST	Tornado Watch	SPC	Baldwin, Choctaw, Mobile, Washington	11 hr
Dec 23, 11:33 AM CST	Mesoscale Discussion	SPC	Choctaw, Greene, Mobile, Sumter, Washington	87 min
Dec 23, 2:06 PM CST	Mesoscale Discussion	SPC	Autauga, Baldwin, Barbour, Bibb, Bullock, Butler and 32 more	114 min
Dec 23, 2:47 PM CST	Tornado Watch	SPC	Autauga, Barbour, Bibb, Bullock, Butler, Chambers and 34 more	8 hr
Dec 23, 2:57 PM CST	Mesoscale Discussion	SPC	Choctaw, Greene, Mobile, Sumter, Washington	93 min
Dec 23, 4:59 PM CST	Mesoscale Discussion	SPC	Baldwin, Mobile, Washington	61 min
Dec 23, 4:19 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 20 more	116 min

Nearby

Mesoscale Discussions in Mississippi, 2014 Mesoscale Discussions in Louisiana, 2014 Mesoscale Discussions in Alabama, 2014 Every mesoscale discussion in 2014

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.