Alert archive / Alabama / Mesoscale Discussions in 2018

Mesoscale Discussion 149

March 19, 20188 counties in Alabama

The Storm Prediction Center issued this mesoscale discussion at Mar 19, 2018, 6:59 PM CDT for 8 counties in Alabama. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Mar 19, 2018, 6:59 PM CDT (23:59 UTC)
Expired: Mar 19, 2018, 8:30 PM CDT
In force: 91 min
Issued by: the Storm Prediction Center

Counties Blount County, AL, Calhoun County, AL, Cherokee County, AL, Cleburne County, AL, Cullman County, AL, Etowah County, AL, Marshall County, AL, St. Clair County, AL

The radar

The Northeast Alabama radar (KHTX), 92 km from the middle of the area, began a volume at 00:03 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 15Mar 19, 8:05 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 12.0 hours before the alert went out and 114 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: 563 J/kg
Mixed-layer CIN: -65 J/kg
Mixed-layer LCL: 505 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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
Mar 19, 9:52 AM CDT	Mesoscale Discussion	SPC	Blount, Calhoun, Cherokee, Colbert, Cullman, DeKalb and 14 more	83 min
Mar 19, 11:18 AM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lauderdale	87 min
Mar 19, 2:06 PM CDT	Mesoscale Discussion	SPC	Blount, Colbert, Cullman, DeKalb, Etowah, Fayette and 14 more	84 min
Mar 19, 3:28 PM CDT	Tornado Watch PDS	SPC	Bibb, Blount, Calhoun, Cherokee, Chilton, Clay and 30 more	9 hr
Mar 19, 5:06 PM CDT	Mesoscale Discussion	SPC	Colbert, Cullman, Franklin, Lawrence, Marion, Morgan and 1 more	114 min

Nearby

Mesoscale Discussions in Alabama, 2018 Every mesoscale discussion in 2018

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.