Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 309

March 29, 2011Chicot County, Arkansas; 21 parishes in Louisiana; 29 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 29, 2011, 7:40 PM CDT for Chicot County, Arkansas; 21 parishes in Louisiana; 29 counties in Mississippi. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Mar 29, 2011, 7:40 PM CDT (00:40 UTC)
Expired: Mar 29, 2011, 9:15 PM CDT
In force: 95 min
Issued by: the Storm Prediction Center

All 51 counties

Chicot County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Attala County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Kemper County, MS, Leake County, MS, Leflore County, MS, Madison 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, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 122 km from the middle of the area, began a volume at 00:43 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 nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 0.7 hours before the alert went out and 112 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: 780 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 504 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 153 m²/s²
0-3 km storm-relative helicity: 257 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.8

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
Mar 29, 8:13 PM CDT	Mesoscale Discussion	SPC	Arkansas, Cleveland, Crittenden, Cross, Dallas, Faulkner and 16 more	2 hr
Mar 29, 8:34 PM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	7 hr
Mar 29, 8:56 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 15 more	64 min
Mar 29, 9:42 PM CDT	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more	7 hr
Mar 29, 10:15 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 7 more	90 min
Mar 29, 11:39 PM CDT	Mesoscale Discussion	SPC	Caldwell, Catahoula, Franklin, Grant, LaSalle, Madison and 1 more	2 hr

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.