Alert archive / Louisiana / Tornado Watches in 2010

Tornado Watch 772

December 31, 201023 parishes in Louisiana; 23 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Dec 31, 2010, 1:34 PM CST for 23 parishes in Louisiana; 23 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Dec 31, 2010, 1:34 PM CST (19:34 UTC)
Expired: Dec 31, 2010, 8:00 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 60 kt

All 46 counties

Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Bolivar County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hinds County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Rankin County, MS, Sharkey County, MS, Simpson County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 60%
One or more EF2 to EF5 tornadoes: 40%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

27 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Dec 31, 1:40 PM CST	Tornado Warning	JAN	Catahoula, Concordia, Franklin, Tensas	65 min
Dec 31, 1:51 PM CST	Tornado Warning	LCH	Rapides	24 min
Dec 31, 2:06 PM CST	Severe Thunderstorm Warning	SHV	Grant, LaSalle	54 min
Dec 31, 2:21 PM CST	Tornado Warning	LCH	Rapides	24 min
Dec 31, 2:39 PM CST	Tornado Warning	JAN	Franklin, Madison, Tensas	42 min
Dec 31, 2:42 PM CST	Severe Thunderstorm Warning	JAN	Catahoula, Concordia	63 min
Dec 31, 3:06 PM CST	Tornado Warning	JAN	Catahoula, Concordia	24 min
Dec 31, 3:18 PM CST	Severe Thunderstorm Warning	JAN	Issaquena, Washington	42 min
Dec 31, 3:19 PM CST	Severe Thunderstorm Warning	JAN	Claiborne, Copiah, Franklin, Jefferson, Lincoln	56 min
Dec 31, 3:23 PM CST	Tornado Warning	JAN	Franklin, Jefferson, Lincoln	37 min
Dec 31, 3:27 PM CST	Severe Thunderstorm Warning	JAN	Concordia, Madison, Tensas	48 min
Dec 31, 3:33 PM CST	Severe Thunderstorm Warning	JAN	Concordia, Tensas	42 min
Dec 31, 3:37 PM CST	Severe Thunderstorm Warning	JAN	Humphreys, Sharkey, Washington	38 min
Dec 31, 3:41 PM CST	Severe Thunderstorm Warning	JAN	East Carroll, Madison, Richland, West Carroll	49 min
Dec 31, 3:51 PM CST	Tornado Warning	JAN	Tensas	24 min
Dec 31, 4:03 PM CST	Tornado Warning	JAN	Copiah	27 min
Dec 31, 4:09 PM CST	Tornado Warning	JAN	Hinds, Warren, Yazoo	26 min
Dec 31, 4:10 PM CST	Flash Flood Warning	JAN	Claiborne, Warren	2 hr
Dec 31, 4:12 PM CST	Severe Thunderstorm Warning	JAN	Hinds, Rankin	63 min
Dec 31, 4:15 PM CST	Tornado Warning	JAN	Claiborne, Jefferson	30 min
Dec 31, 4:37 PM CST	Tornado Warning	JAN	Claiborne, Copiah	23 min
Dec 31, 4:44 PM CST	Tornado Warning Emergency	JAN	Hinds, Rankin	46 min
Dec 31, 4:59 PM CST	Tornado Warning	JAN	Copiah	31 min
Dec 31, 5:12 PM CST	Tornado Warning	JAN	Copiah, Hinds, Rankin, Simpson	33 min
Dec 31, 5:15 PM CST	Tornado Warning	JAN	Leake, Madison, Rankin, Scott	60 min
Dec 31, 5:29 PM CST	Flash Flood Warning	JAN	Copiah, Hinds, Rankin, Simpson	2 hr
Dec 31, 5:36 PM CST	Tornado Warning	JAN	Rankin, Scott, Simpson, Smith	39 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 7.6 hours before the alert went out and 176 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: 100 J/kg
Mixed-layer CIN: -119 J/kg
Mixed-layer LCL: 580 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 343 m²/s²
0-3 km storm-relative helicity: 523 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 31, 9:42 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Livingston, Orleans and 8 more	2 hr
Dec 31, 10:36 AM CST	Mesoscale Discussion	SPC	Bossier, Caddo	114 min
Dec 31, 11:39 AM CST	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more	7 hr
Dec 31, 12:44 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 10 more	2 hr
Dec 31, 2:58 PM CST	Mesoscale Discussion	SPC	East Baton Rouge, East Feliciana, Saint Helena, Tangipahoa, Washington, West Baton Rouge and 1 more	92 min
Dec 31, 3:58 PM CST	Tornado Watch	SPC	Catahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more	7 hr
Dec 31, 5:35 PM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Bolivar, Calhoun, Coahoma, DeSoto and 16 more	115 min

Nearby

Tornado Watches in Louisiana, 2010 Tornado Watches in Mississippi, 2010 Every tornado watch in 2010

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.