Alert archive / Mississippi / Tornado Watches in 2011

Tornado Watch 91

April 4, 20114 states

The Storm Prediction Center issued this tornado watch at Apr 4, 2011, 10:53 AM CDT for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Apr 4, 2011, 10:53 AM CDT (15:53 UTC)
Expired: Apr 4, 2011, 6:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 98 counties

Ashley County, AR, Chicot County, AR, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Bolivar County, MS, Carroll County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Clay County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena 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, Leflore County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Tyler County, TX

The radar

The Jackson/Brandon,MS radar (KDGX), 130 km from the middle of the area, began a volume at 15:52 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.

What SPC expected

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

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 60%
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: 10%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Apr 4, 11:01 AM CDT	Severe Thunderstorm Warning	JAN	Chicot	59 min
Apr 4, 11:42 AM CDT	Severe Thunderstorm Warning	JAN	Ashley, Chicot	63 min
Apr 4, 11:46 AM CDT	Severe Thunderstorm Warning	JAN	Morehouse	44 min
Apr 4, 11:58 AM CDT	Severe Thunderstorm Warning	JAN	Chicot	62 min
Apr 4, 12:25 PM CDT	Severe Thunderstorm Warning	JAN	Carroll, Grenada, Holmes, Humphreys, Leflore, Sunflower and 1 more	65 min
Apr 4, 1:27 PM CDT	Severe Thunderstorm Warning	JAN	Carroll, Grenada, Montgomery	29 min
Apr 4, 1:57 PM CDT	Severe Thunderstorm Warning	JAN	Morehouse	48 min
Apr 4, 2:28 PM CDT	Severe Thunderstorm Warning	JAN	East Carroll, Morehouse, West Carroll	47 min
Apr 4, 2:43 PM CDT	Severe Thunderstorm Warning	JAN	Franklin, Richland	62 min
Apr 4, 2:53 PM CDT	Severe Thunderstorm Warning	JAN	Chicot	52 min
Apr 4, 2:56 PM CDT	Severe Thunderstorm Warning	JAN	Madison	33 min
Apr 4, 3:02 PM CDT	Tornado Warning	JAN	Catahoula, Franklin	58 min
Apr 4, 3:04 PM CDT	Severe Thunderstorm Warning	LCH	Rapides, Vernon	41 min
Apr 4, 3:12 PM CDT	Severe Thunderstorm Warning	LCH	Allen, Beauregard	63 min
Apr 4, 3:15 PM CDT	Severe Thunderstorm Warning	JAN	East Carroll, West Carroll	35 min
Apr 4, 3:20 PM CDT	Severe Thunderstorm Warning	JAN	Holmes, Humphreys, Leflore, Sunflower	24 min
Apr 4, 3:25 PM CDT	Severe Thunderstorm Warning	JAN	Yazoo	35 min
Apr 4, 3:26 PM CDT	Severe Thunderstorm Warning	JAN	Catahoula, Concordia	49 min
Apr 4, 3:34 PM CDT	Severe Thunderstorm Warning	JAN	Clay, Lowndes, Oktibbeha	56 min
Apr 4, 3:35 PM CDT	Severe Thunderstorm Warning	JAN	East Carroll, Madison	55 min
Apr 4, 3:42 PM CDT	Severe Thunderstorm Warning	LCH	Avoyelles, Rapides	48 min
Apr 4, 3:43 PM CDT	Tornado Warning	JAN	Tensas	48 min
Apr 4, 3:51 PM CDT	Severe Thunderstorm Warning	LCH	Allen, Evangeline	39 min
Apr 4, 3:53 PM CDT	Severe Thunderstorm Warning	JAN	Attala, Choctaw, Winston	67 min
Apr 4, 3:54 PM CDT	Severe Thunderstorm Warning	JAN	Madison	51 min
Apr 4, 3:56 PM CDT	Tornado Warning	LCH	Evangeline	34 min
Apr 4, 3:58 PM CDT	Severe Thunderstorm Warning	JAN	Catahoula, Concordia	62 min
Apr 4, 4:07 PM CDT	Tornado Warning	JAN	Claiborne, Warren	53 min
Apr 4, 4:14 PM CDT	Severe Thunderstorm Warning	JAN	Hinds, Madison, Yazoo	46 min
Apr 4, 4:19 PM CDT	Tornado Warning	LCH	Evangeline, Saint Landry	26 min
Apr 4, 4:24 PM CDT	Severe Thunderstorm Warning	LCH	Avoyelles	22 min
Apr 4, 4:27 PM CDT	Tornado Warning	JAN	Hinds, Madison	48 min
Apr 4, 4:28 PM CDT	Severe Thunderstorm Warning	JAN	Lowndes	32 min
Apr 4, 4:31 PM CDT	Severe Thunderstorm Warning	LIX	Pointe Coupee, West Feliciana	74 min
Apr 4, 4:36 PM CDT	Flash Flood Warning	JAN	Hinds, Madison, Rankin	3 hr
Apr 4, 4:39 PM CDT	Severe Thunderstorm Warning	JAN	Claiborne, Copiah, Franklin, Jefferson, Lincoln	66 min
Apr 4, 4:40 PM CDT	Flash Flood Warning	JAN	Attala, Choctaw, Clay, Lowndes, Noxubee, Oktibbeha and 1 more	2 hr
Apr 4, 4:57 PM CDT	Severe Thunderstorm Warning	JAN	Leake, Madison	48 min
Apr 4, 5:02 PM CDT	Severe Thunderstorm Warning	JAN	Lowndes, Noxubee, Oktibbeha, Winston	58 min
Apr 4, 5:06 PM CDT	Tornado Warning	JAN	Rankin	54 min
Apr 4, 5:16 PM CDT	Flash Flood Warning	JAN	Attala, Leake, Madison	119 min
Apr 4, 5:20 PM CDT	Severe Thunderstorm Warning	LIX	Amite, Wilkinson	55 min
Apr 4, 5:21 PM CDT	Severe Thunderstorm Warning	JAN	Rankin, Simpson	39 min
Apr 4, 5:34 PM CDT	Severe Thunderstorm Warning	JAN	Neshoba, Winston	31 min
Apr 4, 5:36 PM CDT	Severe Thunderstorm Warning	LIX	Ascension, East Baton Rouge, Iberville, Livingston, West Baton Rouge	54 min
Apr 4, 5:39 PM CDT	Tornado Warning	JAN	Rankin, Simpson, Smith	51 min
Apr 4, 5:45 PM CDT	Severe Thunderstorm Warning	LIX	East Baton Rouge, East Feliciana, Saint Helena, West Baton Rouge	60 min
Apr 4, 5:47 PM CDT	Severe Thunderstorm Warning	LIX	Pike, Walthall	58 min
Apr 4, 5:48 PM CDT	Severe Thunderstorm Warning	JAN	Jefferson Davis, Lawrence, Lincoln	42 min
Apr 4, 5:50 PM CDT	Severe Thunderstorm Warning	JAN	Kemper, Neshoba, Noxubee, Winston	55 min
Apr 4, 5:56 PM CDT	Tornado Warning	JAN	Jefferson Davis, Lawrence	64 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, 3.9 hours before the alert went out and 122 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: 1411 J/kg
Mixed-layer CIN: -115 J/kg
Mixed-layer LCL: 704 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 223 m²/s²
0-3 km storm-relative helicity: 425 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 2.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

719 
WWUS20 KWNS 041555
SEL1  
SPC WW 041555
ARZ000-LAZ000-MSZ000-TXZ000-CWZ000-042300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 91
NWS STORM PREDICTION CENTER NORMAN OK
1055 AM CDT MON APR 4 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       EXTREME SOUTHEAST ARKANSAS
       SOUTHERN LOUISIANA
       CENTRAL MISSISSIPPI
       EXTREME SOUTHEAST TEXAS
       COASTAL WATERS

EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1055 AM UNTIL 600
PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 125 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES WEST NORTHWEST OF
COLUMBUS MISSISSIPPI TO 35 MILES SOUTH SOUTHWEST OF LAKE CHARLES
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 87...WW 88...WW 89...WW
90...

DISCUSSION...WELL-DEVELOPED SQUALL ALONG THE COLD FRONT WILL
PROGRESS EWD AND PERSIST THROUGH THE AFTERNOON.  A CONTINUED FEED OF
66-72 F DEWPOINTS AND MODEST SURFACE HEATING WILL RESULT IN MODERATE
INSTABILITY AHEAD OF THE LINE...WHILE DEEP-LAYER SWLY FLOW WILL
PROVIDE SUFFICIENT VERTICAL SHEAR FOR ORGANIZED/EMBEDDED BOWS AND
POSSIBLY SOME SUPERCELL STRUCTURES.  DAMAGING WINDS WILL BE THE MAIN
THREAT...THOUGH A FEW TORNADOES WILL ALSO BE POSSIBLE WITH
CIRCULATIONS EMBEDDED IN THE LINE.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 26040.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 4, 10:25 AM CDT	Mesoscale Discussion	SPC	Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 9 more	2 hr
Apr 4, 1:03 PM CDT	Tornado Watch	SPC	Blount, Colbert, Cullman, DeKalb, Fayette, Franklin and 16 more	7 hr
Apr 4, 2:52 PM CDT	Mesoscale Discussion	SPC	Choctaw, Fayette, Greene, Pickens, Sumter, Tuscaloosa	113 min
Apr 4, 4:28 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Bullock, Butler, Calhoun, Chambers and 29 more	62 min
Apr 4, 4:55 PM CDT	Tornado Watch	SPC	Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 28 more	6 hr
Apr 4, 5:28 PM CDT	Tornado Watch	SPC	Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more	7 hr
Apr 4, 6:50 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Bibb, Blount, Butler, Calhoun and 36 more	85 min
Apr 3, 9:51 PM CDT	Mesoscale Discussion	SPC	Benton, Crawford, Madison, Washington	84 min
Apr 4, 1:29 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll	91 min
Apr 4, 3:00 AM CDT	Mesoscale Discussion	SPC	Clark, Conway, Dallas, Faulkner, Garland, Grant and 20 more	3 hr
Apr 4, 3:44 AM CDT	Severe Thunderstorm Watch	SPC	Bradley, Calhoun, Clark, Cleburne, Cleveland, Columbia and 37 more	7 hr
Apr 4, 5:48 AM CDT	Mesoscale Discussion	SPC	Baxter, Clark, Clay, Cleburne, Conway, Craighead and 41 more	117 min
Apr 4, 7:22 AM CDT	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 42 more	7 hr
Apr 4, 7:44 AM CDT	Severe Thunderstorm Watch	SPC	Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more	8 hr
Apr 4, 11:20 AM CDT	Mesoscale Discussion	SPC	Beauregard, Bienville, Caldwell, Claiborne, De Soto, Grant and 12 more	115 min

Nearby

Tornado Watches in Mississippi, 2011 Tornado Watches in Louisiana, 2011 Tornado Watches in Texas, 2011 Every tornado watch in 2011

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.