Alert archive / Alabama / Mesoscale Discussions in 2020

Mesoscale Discussion 1368

July 31, 202016 counties in Alabama; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2020, 5:23 PM CDT for 16 counties in Alabama; 5 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 31, 2020, 5:23 PM CDT (22:23 UTC)
Expired: Jul 31, 2020, 7:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 407

All 21 counties

Blount County, AL, Calhoun County, AL, Cullman County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Marion County, AL, Marshall County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Clay County, MS, Lowndes County, MS, Monroe County, MS, Noxubee County, MS, Oktibbeha County, MS

The radar

The Birmingham radar (KBMX), 81 km from the middle of the area, began a volume at 22:22 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

Birmingham, AL (KBMX), launched 12:00Z, 10.4 hours before the alert went out and 79 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: 922 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 835 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 137 m²/s²
0-3 km storm-relative helicity: 131 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

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
Jul 31, 1:29 PM CDT	Mesoscale Discussion	SPC	Blount, Calhoun, Cherokee, Cullman, DeKalb, Etowah and 10 more	91 min
Jul 31, 12:35 PM CDT	Mesoscale Discussion	SPC	Attala, Calhoun, Carroll, Choctaw, Claiborne, Grenada and 20 more	85 min
Jul 31, 1:21 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Attala, Bolivar, Calhoun, Carroll, Choctaw and 33 more	7 hr

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.