Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 444

April 15, 201152 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; 4 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2011, 7:16 PM CDT for 52 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; 4 counties in Mississippi. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2011, 7:16 PM CDT (00:16 UTC)
Expired: Apr 15, 2011, 8:15 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center

All 59 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Cullman County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Etowah County, AL, Fayette County, AL, Geneva County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar 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, Pickens County, AL, Pike County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, George County, MS, Greene County, MS, Jackson County, MS, Stone County, MS

The radar

The Birmingham radar (KBMX), 130 km from the middle of the area, began a volume at 00:17 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 146Apr 15, 7:45 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 0.3 hours before the alert went out and 237 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: 173 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 1488 m above ground
0-6 km bulk shear: 74 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 165 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

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 15, 7:48 PM CDT	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bibb, Bullock, Butler and 34 more	6 hr
Apr 15, 10:41 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Chambers and 28 more	94 min
Apr 16, 1:43 AM CDT	Mesoscale Discussion	SPC	Coffee, Dale, Geneva, Henry, Houston	92 min
Apr 16, 2:05 AM CDT	Tornado Watch	SPC	Barbour, Bullock, Coffee, Covington, Dale, Geneva and 5 more	7 hr
Apr 16, 6:57 AM CDT	Mesoscale Discussion	SPC	Baker, Columbia, Hamilton, Lafayette, Madison, Nassau and 3 more	63 min
Apr 15, 7:51 PM CDT	Mesoscale Discussion	SPC	Clarke, Covington, Forrest, Hancock, Jasper, Jefferson Davis and 15 more	54 min

Nearby

Mesoscale Discussions in Alabama, 2011 Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Florida, 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.