Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 353

April 4, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2011, 6:50 PM CDT for 4 states. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Apr 4, 2011, 6:50 PM CDT (23:50 UTC)
Expired: Apr 4, 2011, 8:15 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 88 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Blount County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Conecuh County, AL, Coosa County, AL, Crenshaw County, AL, Dallas County, AL, DeKalb County, AL, Elmore County, AL, Escambia County, AL, Etowah County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Marshall County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, Bartow County, GA, Carroll County, GA, Chattooga County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Fulton County, GA, Haralson County, GA, Heard County, GA, Paulding County, GA, Polk County, GA, Troup County, GA, Ascension Parish, LA, Assumption Parish, LA, Iberia Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Clarke County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jones County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 83 km from the middle of the area, began a volume at 23:53 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

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.8 hours before the alert went out and 170 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: 1669 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 624 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 245 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
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, 3:49 PM CDT	Mesoscale Discussion	SPC	Catoosa, Dade, Fannin, Gilmer, Gordon, Murray and 4 more	56 min
Apr 4, 7:44 AM CDT	Severe Thunderstorm Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more	8 hr
Apr 4, 10:53 AM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	7 hr
Apr 4, 11:20 AM CDT	Mesoscale Discussion	SPC	Beauregard, Bienville, Caldwell, Claiborne, De Soto, Grant and 12 more	115 min
Apr 4, 7:22 AM CDT	Tornado Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more	7 hr

Nearby

Mesoscale Discussions in Alabama, 2011 Mesoscale Discussions in Georgia, 2011 Mesoscale Discussions in Louisiana, 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.