Alert archive / Alabama / Mesoscale Discussions in 2020

Mesoscale Discussion 368

April 12, 202022 counties in Alabama; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2020, 7:36 PM CDT for 22 counties in Alabama; 5 counties in Mississippi. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Apr 12, 2020, 7:36 PM CDT (00:36 UTC)
Expired: Apr 12, 2020, 9:00 PM CDT
In force: 84 min
Issued by: the Storm Prediction Center

All 27 counties

Autauga County, AL, Bibb County, AL, Blount County, AL, Calhoun County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Coosa County, AL, Dallas County, AL, Etowah County, AL, Hale County, AL, Jefferson County, AL, Lowndes County, AL, Marengo County, AL, Monroe County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Washington County, AL, Wilcox County, AL, Clarke County, MS, George County, MS, Greene County, MS, Perry County, MS, Wayne County, MS

The radar

The Birmingham radar (KBMX), 150 km from the middle of the area, began a volume at 00:35 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 115Apr 12, 10:45 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 0.6 hours before the alert went out and 150 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: 533 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 847 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 401 m²/s²
0-3 km storm-relative helicity: 509 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 8.4

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 8:50 PM CDT	Mesoscale Discussion	SPC	Blount, Cullman, Etowah, Jefferson, St. Clair, Shelby and 2 more	55 min
Apr 12, 10:28 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Calhoun and 32 more	92 min
Apr 12, 10:45 PM CDT	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Calhoun and 26 more	8 hr
Apr 12, 11:19 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lamar, Lauderdale, Lawrence, Marion	86 min
Apr 12, 7:56 PM CDT	Mesoscale Discussion	SPC	Bolivar, Carroll, Coahoma, DeSoto, Grenada, Holmes and 14 more	2 hr
Apr 12, 8:19 PM CDT	Severe Thunderstorm Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more	4 hr
Apr 12, 9:44 PM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 37 more	91 min

Nearby

Mesoscale Discussions in Alabama, 2020 Mesoscale Discussions in Mississippi, 2020 Every mesoscale discussion in 2020

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.