Alert archive / Tennessee / Mesoscale Discussions in 2020

Mesoscale Discussion 121

February 12, 20209 counties in Alabama; 11 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Feb 12, 2020, 6:00 PM CST for 9 counties in Alabama; 11 counties in Tennessee. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Feb 12, 2020, 6:00 PM CST (00:00 UTC)
Expired
Feb 12, 2020, 7:30 PM CST
In force
90 min
Issued by
the Storm Prediction Center

Counties Cullman County, AL, Fayette County, AL, Lamar County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Bedford County, TN, Cannon County, TN, Coffee County, TN, DeKalb County, TN, Franklin County, TN, Giles County, TN, Lincoln County, TN, Marshall County, TN, Moore County, TN, Rutherford County, TN, Warren County, TN

The radar

The Northeast Alabama radar (KHTX), 82 km from the middle of the area, began a volume at 00:02 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

Nashville Metro, TN (KBNA), launched 00:00Z, 0.0 hours before the alert went out and 157 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-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2020-02-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2020-02-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 775 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
99 kt
0-1 km storm-relative helicity
775 m²/s²
0-3 km storm-relative helicity
947 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

IssuedProductOfficeCountiesLasted
Feb 12, 7:37 PM CSTMesoscale DiscussionSPCBlount, Cherokee, Cullman, DeKalb, Etowah, Jackson and 4 more83 min

Nearby

Mesoscale Discussions in Tennessee, 2020Mesoscale Discussions in Alabama, 2020Every 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.