Alert archive / Mississippi / Severe Thunderstorm Watches in 2007

Severe Thunderstorm Watch 736

November 21, 200725 parishes in Louisiana; 57 counties in Mississippi; 20 counties in Tennessee

The Storm Prediction Center issued this severe thunderstorm watch at Nov 21, 2007, 5:29 PM CST for 25 parishes in Louisiana; 57 counties in Mississippi; 20 counties in Tennessee. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Nov 21, 2007, 5:29 PM CST (23:29 UTC)
Expired: Nov 21, 2007, 11:00 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 102 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Calcasieu Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Alcorn County, MS, Amite County, MS, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Coahoma County, MS, Copiah County, MS, DeSoto County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Jefferson County, MS, Lafayette County, MS, Lawrence County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pike County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

What SPC expected

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

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 5%
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

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

Issued	Product	Office	Counties	Lasted
Nov 21, 5:46 PM CST	Severe Thunderstorm Warning	LCH	Allen, Beauregard, Calcasieu, Jefferson Davis, Rapides, Vernon	59 min
Nov 21, 6:05 PM CST	Severe Thunderstorm Warning	MEG	Obion, Weakley	40 min
Nov 21, 6:12 PM CST	Severe Thunderstorm Warning	MEG	Dyer, Gibson, Weakley	48 min
Nov 21, 6:32 PM CST	Severe Thunderstorm Warning	MEG	Coahoma	58 min
Nov 21, 6:34 PM CST	Severe Thunderstorm Warning	MEG	Henry	41 min
Nov 21, 6:40 PM CST	Severe Thunderstorm Warning	LCH	Allen, Avoyelles, Evangeline, Rapides, Saint Landry	65 min
Nov 21, 6:52 PM CST	Tornado Warning	MEG	Henry	38 min
Nov 21, 6:57 PM CST	Severe Thunderstorm Warning	JAN	Concordia, Tensas	48 min
Nov 21, 7:03 PM CST	Severe Thunderstorm Warning	LIX	Wilkinson	42 min
Nov 21, 7:09 PM CST	Severe Thunderstorm Warning	MEG	Quitman	51 min
Nov 21, 7:21 PM CST	Severe Thunderstorm Warning	MEG	Chester, Henderson, Madison	39 min
Nov 21, 7:33 PM CST	Severe Thunderstorm Warning	LIX	Pointe Coupee, West Feliciana	42 min
Nov 21, 7:36 PM CST	Severe Thunderstorm Warning	MEG	Panola, Tallahatchie	69 min
Nov 21, 7:39 PM CST	Severe Thunderstorm Warning	LCH	Beauregard, Calcasieu, Cameron	51 min
Nov 21, 7:44 PM CST	Severe Thunderstorm Warning	JAN	East Carroll, West Carroll	31 min
Nov 21, 7:46 PM CST	Severe Thunderstorm Warning	LIX	Amite, Wilkinson	29 min
Nov 21, 7:49 PM CST	Severe Thunderstorm Warning	JAN	Adams, Franklin	37 min
Nov 21, 8:24 PM CST	Severe Thunderstorm Warning	MEG	Calhoun, Lafayette, Panola, Tallahatchie, Yalobusha	53 min
Nov 21, 8:27 PM CST	Severe Thunderstorm Warning	JAN	Humphreys, Sharkey, Washington	33 min
Nov 21, 8:32 PM CST	Severe Thunderstorm Warning	LIX	Iberville, Pointe Coupee, West Baton Rouge	28 min
Nov 21, 9:03 PM CST	Severe Thunderstorm Warning	LIX	Saint Helena	14 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

Little Rock, AR (KLZK), launched 12:00Z, 11.5 hours before the alert went out and 94 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: 91 J/kg
Mixed-layer CIN: -84 J/kg
Mixed-layer LCL: 805 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 21, 11:17 AM CST	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Bradley, Calhoun, Chicot and 58 more	118 min
Nov 21, 12:47 PM CST	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 43 more	6 hr
Nov 21, 2:29 PM CST	Severe Thunderstorm Watch	SPC	Ashley, Chicot, Columbia, Lafayette, Miller, Union	8 hr
Nov 21, 3:18 PM CST	Mesoscale Discussion	SPC	Arkansas, Clark, Clay, Cleburne, Cleveland, Conway and 34 more	87 min
Nov 21, 5:10 PM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Columbia, Union	65 min
Nov 21, 12:24 PM CST	Mesoscale Discussion	SPC	Ascension, East Baton Rouge, East Feliciana, Iberville, Lafayette, Livingston and 13 more	2 hr
Nov 21, 1:32 PM CST	Mesoscale Discussion	SPC	Beauregard, Bienville, Bossier, Caddo, Claiborne, De Soto and 9 more	118 min
Nov 21, 12:28 PM CST	Mesoscale Discussion	SPC	Atchison, Gentry, Harrison, Holt, Mercer, Nodaway and 3 more	5 hr

Nearby

Severe Thunderstorm Watches in Mississippi, 2007 Severe Thunderstorm Watches in Louisiana, 2007 Severe Thunderstorm Watches in Tennessee, 2007 Every severe thunderstorm watch in 2007

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.