Alert archive / Mississippi / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 74

March 29, 2011Ashley County, Chicot County, Arkansas; 26 parishes in Louisiana; 38 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at Mar 29, 2011, 6:26 PM CDT for Ashley County, Chicot County, Arkansas; 26 parishes in Louisiana; 38 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Mar 29, 2011, 6:26 PM CDT (23:26 UTC)
Expired
Mar 30, 2011, 2:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 66 counties

Ashley County, AR, Chicot County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 155 km from the middle of the area, began a volume at 23:30 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
20%
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
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 29, 6:31 PM CDTSevere Thunderstorm WarningJANFranklin, Madison, Tensas59 min
Mar 29, 7:00 PM CDTSevere Thunderstorm WarningJANMadison, Tensas60 min
Mar 29, 7:18 PM CDTSevere Thunderstorm WarningJANChicot57 min
Mar 29, 7:18 PM CDTSevere Thunderstorm WarningSHVBienville, Claiborne, Webster42 min
Mar 29, 7:22 PM CDTSevere Thunderstorm WarningJANCopiah, Hinds, Rankin, Simpson53 min
Mar 29, 7:29 PM CDTSevere Thunderstorm WarningMEGChickasaw, Itawamba, Lee, Monroe47 min
Mar 29, 7:33 PM CDTSevere Thunderstorm WarningJANMadison, Tensas27 min
Mar 29, 7:58 PM CDTSevere Thunderstorm WarningJANClaiborne, Hinds, Warren62 min
Mar 29, 8:16 PM CDTSevere Thunderstorm WarningJANRankin, Scott44 min
Mar 29, 8:31 PM CDTSevere Thunderstorm WarningJANLeake, Neshoba, Newton59 min
Mar 29, 8:46 PM CDTSevere Thunderstorm WarningJANCopiah, Hinds, Madison, Rankin, Simpson74 min
Mar 29, 8:49 PM CDTFlash Flood WarningJANHinds, Rankin116 min
Mar 29, 9:14 PM CDTSevere Thunderstorm WarningJANCarroll, Grenada, Leflore61 min
Mar 29, 9:31 PM CDTSevere Thunderstorm WarningMEGTallahatchie, Yalobusha44 min
Mar 29, 9:45 PM CDTSevere Thunderstorm WarningJANKemper, Lauderdale60 min
Mar 29, 9:55 PM CDTFlash Flood WarningJANScott2 hr
Mar 29, 9:58 PM CDTSevere Thunderstorm WarningJANGrenada17 min
Mar 29, 10:07 PM CDTFlash Flood WarningJANFranklin, Madison, Tensas113 min
Mar 29, 10:08 PM CDTSevere Thunderstorm WarningMEGCalhoun, Lafayette, Yalobusha42 min
Mar 29, 10:09 PM CDTSevere Thunderstorm WarningJANLowndes21 min
Mar 29, 10:23 PM CDTFlash Flood WarningJANMadison, Tensas2 hr
Mar 29, 10:29 PM CDTSevere Thunderstorm WarningMEGItawamba, Monroe30 min
Mar 29, 10:38 PM CDTSevere Thunderstorm WarningMEGCalhoun, Lafayette, Pontotoc, Union33 min
Mar 29, 10:39 PM CDTFlash Flood WarningJANHinds, Rankin3 hr
Mar 29, 11:54 PM CDTFlash Flood WarningJANScott3 hr
Mar 30, 12:39 AM CDTSevere Thunderstorm WarningJANFranklin, Madison, Tensas56 min
Mar 30, 1:01 AM CDTSevere Thunderstorm WarningJANConcordia, Tensas15 min
Mar 30, 1:31 AM CDTSevere Thunderstorm WarningJANMadison22 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, 11.4 hours before the alert went out and 145 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, Jackson, MS at 12:00Z on 2011-03-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Jackson, MS at 12:00Z on 2011-03-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 272 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
463 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
272 m²/s²
0-3 km storm-relative helicity
300 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 29, 5:26 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Columbia, Desha and 3 more2 hr
Mar 29, 2:48 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Beauregard, Calcasieu and 29 more87 min
Mar 29, 3:17 PM CDTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 34 more7 hr
Mar 29, 6:47 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 33 more118 min

Nearby

Severe Thunderstorm Watches in Mississippi, 2011Severe Thunderstorm Watches in Louisiana, 2011Severe Thunderstorm Watches in Arkansas, 2011Every severe thunderstorm 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.