Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 170

February 28, 20114 counties in Arkansas; 6 parishes in Louisiana; 56 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2011, 5:28 AM CST for 4 counties in Arkansas; 6 parishes in Louisiana; 56 counties in Mississippi. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Feb 28, 2011, 5:28 AM CST (11:28 UTC)
Expired: Feb 28, 2011, 6:30 AM CST
In force: 62 min
Issued by: the Storm Prediction Center

All 66 counties

Ashley County, AR, Chicot County, AR, Desha County, AR, Phillips County, AR, East Carroll Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, West Carroll Parish, LA, Alcorn 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, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Jasper County, MS, Kemper County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith 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, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 104 km from the middle of the area, began a volume at 11:30 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 31Feb 28, 6:00 AM CST

The nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 11.5 hours before the alert went out and 193 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: 836 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 917 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 442 m²/s²
0-3 km storm-relative helicity: 556 m²/s²
Significant tornado parameter: 3.1
Supercell composite: 11.5

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 27, 8:07 PM CST	Mesoscale Discussion	SPC	Crawford, Franklin, Howard, Little River, Logan, Madison and 7 more	53 min
Feb 27, 10:04 PM CST	Tornado Watch	SPC	Baxter, Benton, Boone, Carroll, Clark, Cleburne and 41 more	6 hr
Feb 27, 11:49 PM CST	Mesoscale Discussion	SPC	Clark, Conway, Crawford, Franklin, Garland, Hempstead and 20 more	86 min
Feb 28, 1:05 AM CST	Mesoscale Discussion	SPC	Clay, Craighead, Crittenden, Cross, Greene, Mississippi and 2 more	25 min
Feb 28, 1:33 AM CST	Tornado Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lawrence and 4 more	7 hr
Feb 28, 5:59 AM CST	Tornado Watch	SPC	Lee, Phillips	7 hr
Feb 28, 5:47 AM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Calhoun, Chickasaw, Clay, Grenada and 14 more	28 min
Feb 28, 11:25 AM CST	Mesoscale Discussion	SPC	Calhoun, Carroll, Chickasaw, Choctaw, Clay, Itawamba and 9 more	95 min
Feb 28, 5:16 PM CST	Mesoscale Discussion	SPC	George, Greene, Jackson, Perry	89 min

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Arkansas, 2011 Every mesoscale discussion 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.