Alert archive / Mississippi / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 51

February 29, 20126 parishes in Louisiana; 24 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at Feb 29, 2012, 2:15 PM CST for 6 parishes in Louisiana; 24 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Feb 29, 2012, 2:15 PM CST (20:15 UTC)
Expired: Feb 29, 2012, 8:30 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 30 counties

East Carroll Parish, LA, Franklin Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Richland Parish, LA, West Carroll Parish, LA, Attala County, MS, Bolivar County, MS, Carroll County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 78 km from the middle of the area, began a volume at 20:16 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: 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

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

Issued	Product	Office	Counties	Lasted
Feb 29, 3:07 PM CST	Severe Thunderstorm Warning	JAN	Humphreys, Sunflower, Washington	38 min
Feb 29, 3:40 PM CST	Severe Thunderstorm Warning	JAN	East Carroll, Morehouse, Richland, West Carroll	50 min
Feb 29, 3:46 PM CST	Severe Thunderstorm Warning	JAN	Holmes, Humphreys, Leflore, Sunflower	44 min
Feb 29, 3:47 PM CST	Tornado Warning	JAN	Holmes, Humphreys, Leflore, Sunflower	43 min
Feb 29, 4:06 PM CST	Severe Thunderstorm Warning	JAN	East Carroll	39 min
Feb 29, 4:19 PM CST	Severe Thunderstorm Warning	JAN	Attala, Carroll, Holmes	41 min
Feb 29, 4:32 PM CST	Severe Thunderstorm Warning	JAN	East Carroll	43 min
Feb 29, 4:48 PM CST	Severe Thunderstorm Warning	JAN	Issaquena, Sharkey, Warren, Yazoo	42 min
Feb 29, 4:57 PM CST	Severe Thunderstorm Warning	JAN	Attala, Choctaw, Montgomery	33 min
Feb 29, 5:09 PM CST	Severe Thunderstorm Warning	JAN	Holmes, Humphreys, Yazoo	36 min
Feb 29, 5:28 PM CST	Severe Thunderstorm Warning	JAN	Attala, Choctaw, Oktibbeha, Winston	35 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, 8.3 hours before the alert went out and 69 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: 883 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 510 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 256 m²/s²
0-3 km storm-relative helicity: 354 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 4.6

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
Feb 29, 11:46 AM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Claiborne, East Carroll, Jackson, Lincoln and 8 more	89 min
Feb 29, 12:49 AM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Bolivar, Calhoun, Carroll, Coahoma and 19 more	56 min
Feb 29, 1:48 PM CST	Tornado Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more	7 hr
Feb 29, 3:34 PM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Marshall	116 min

Nearby

Severe Thunderstorm Watches in Mississippi, 2012 Severe Thunderstorm Watches in Louisiana, 2012 Every severe thunderstorm watch in 2012

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.