Alert archive / Alabama / Mesoscale Discussions in 2014

Mesoscale Discussion 462

April 28, 201419 counties in Alabama; 14 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2014, 5:56 PM CDT for 19 counties in Alabama; 14 counties in Georgia. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Apr 28, 2014, 5:56 PM CDT (22:56 UTC)
Expired: Apr 28, 2014, 7:00 PM CDT
In force: 64 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 33 counties

Autauga County, AL, Bibb County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Elmore County, AL, Etowah County, AL, Hale County, AL, Lee County, AL, Perry County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Bartow County, GA, Carroll County, GA, Chattooga County, GA, Cherokee County, GA, Cobb County, GA, Coweta County, GA, Douglas County, GA, Floyd County, GA, Fulton County, GA, Haralson County, GA, Heard County, GA, Paulding County, GA, Polk County, GA, Troup County, GA

The radar

The Birmingham radar (KBMX), 59 km from the middle of the area, began a volume at 22:59 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 10.9 hours before the alert went out and 60 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: 1223 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 477 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 268 m²/s²
0-3 km storm-relative helicity: 428 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.4

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 28, 6:57 AM CDT	Mesoscale Discussion	SPC	Lauderdale	2 hr
Apr 28, 9:53 AM CDT	Mesoscale Discussion	SPC	Fayette, Lamar, Marion, Pickens	97 min
Apr 28, 12:05 PM CDT	Mesoscale Discussion	SPC	Colbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 6 more	115 min
Apr 28, 12:39 PM CDT	Tornado Watch PDS	SPC	Colbert, Cullman, DeKalb, Fayette, Franklin, Greene and 14 more	8 hr
Apr 28, 2:09 PM CDT	Mesoscale Discussion	SPC	Blount, Colbert, Cullman, Fayette, Franklin, Jackson and 13 more	66 min
Apr 28, 3:49 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lamar, Lawrence, Limestone, Marion and 1 more	86 min
Apr 28, 5:22 PM CDT	Mesoscale Discussion	SPC	Colbert, Cullman, Fayette, Franklin, Jackson, Lamar and 9 more	83 min
Apr 28, 5:37 PM CDT	Tornado Watch PDS	SPC	Catoosa, Dade, Murray, Walker, Whitfield	6 hr
Apr 28, 6:11 PM CDT	Tornado Watch	SPC	Bartow, Bibb, Butts, Carroll, Catoosa, Chattahoochee and 50 more	110 min

Nearby

Mesoscale Discussions in Alabama, 2014 Mesoscale Discussions in Georgia, 2014 Every mesoscale discussion in 2014

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.