Alert archive / Tennessee / Mesoscale Discussions in 2020

Mesoscale Discussion 30

January 11, 20204 states

The Storm Prediction Center issued this mesoscale discussion at Jan 11, 2020, 6:12 AM CST for 4 states. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jan 11, 2020, 6:12 AM CST (12:12 UTC)
Expired: Jan 11, 2020, 7:45 AM CST
In force: 93 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 40 counties

Colbert County, AL, Lauderdale County, AL, Limestone County, AL, Madison County, AL, Spencer County, IN, Butler County, KY, Caldwell County, KY, Christian County, KY, Daviess County, KY, Hancock County, KY, Henderson County, KY, Hopkins County, KY, Logan County, KY, McLean County, KY, Muhlenberg County, KY, Ohio County, KY, Simpson County, KY, Todd County, KY, Trigg County, KY, Webster County, KY, Benton County, TN, Cheatham County, TN, Davidson County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Perry County, TN, Robertson County, TN, Stewart County, TN, Sumner County, TN, Wayne County, TN, Williamson County, TN

The radar

The Ft Campbell radar (KHPX), 10 km from the middle of the area, began a volume at 12:11 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 12Jan 11, 7:00 AM CST

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 0.2 hours before the alert went out and 93 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 819 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 633 m²/s²
0-3 km storm-relative helicity: 864 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.

Issued	Product	Office	Counties	Lasted
Jan 11, 6:57 AM CST	Tornado Watch	SPC	Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 7 more	7 hr
Jan 11, 7:39 AM CST	Mesoscale Discussion	SPC	Choctaw, Clarke, Greene, Hale, Marengo, Mobile and 3 more	96 min
Jan 11, 7:57 AM CST	Tornado Watch	SPC	Autauga, Baldwin, Bibb, Blount, Butler, Chilton and 22 more	9 hr
Jan 11, 9:28 AM CST	Mesoscale Discussion	SPC	Blount, Cullman, DeKalb, Fayette, Jackson, Lawrence and 7 more	92 min
Jan 11, 9:54 AM CST	Mesoscale Discussion	SPC	Choctaw, Greene, Marengo, Pickens, Sumter, Washington	96 min
Jan 11, 11:50 AM CST	Mesoscale Discussion	SPC	Bibb, Blount, Chilton, Choctaw, Clarke, Cullman and 15 more	85 min
Jan 11, 12:20 PM CST	Mesoscale Discussion	SPC	Blount, Calhoun, Chambers, Cherokee, Clay, Cleburne and 9 more	85 min
Jan 11, 12:42 PM CST	Tornado Watch	SPC	Barbour, Bullock, Calhoun, Chambers, Cherokee, Clay and 15 more	7 hr
Jan 11, 1:15 PM CST	Mesoscale Discussion	SPC	Blount, Calhoun, Cherokee, Chilton, DeKalb, Etowah and 6 more	90 min
Jan 11, 2:26 PM CST	Mesoscale Discussion	SPC	Barbour, Bullock, Butler, Coffee, Covington, Crenshaw and 10 more	94 min
Jan 11, 2:44 PM CST	Tornado Watch	SPC	Coffee, Dale, Geneva, Henry, Houston	5 hr
Jan 11, 3:16 PM CST	Mesoscale Discussion	SPC	Bullock, Chambers, Clay, Cleburne, Lee, Macon and 3 more	89 min
Jan 11, 5:21 PM CST	Mesoscale Discussion	SPC	Houston	114 min
Jan 11, 8:20 AM CST	Mesoscale Discussion	SPC	Clark, Crawford, Dearborn, Floyd, Harrison, Jackson and 8 more	55 min
Jan 11, 8:36 AM CST	Severe Thunderstorm Watch	SPC	Clark, Dearborn, Floyd, Harrison, Jefferson, Ohio and 4 more	7 hr
Jan 11, 11:35 AM CST	Mesoscale Discussion	SPC	Adair, Anderson, Bath, Bourbon, Boyle, Bracken and 48 more	85 min
Jan 11, 5:36 PM CST	Mesoscale Discussion	SPC	Letcher, Pike	84 min
Jan 10, 11:58 PM CST	Tornado Watch	SPC	Crockett, Dyer, Fayette, Gibson, Haywood, Lake and 4 more	7 hr
Jan 11, 3:52 AM CST	Mesoscale Discussion	SPC	Crockett, Dyer, Fayette, Hardeman, Haywood, Lauderdale and 3 more	83 min
Jan 11, 4:17 AM CST	Tornado Watch	SPC	Benton, Carroll, Chester, Decatur, Hardeman, Hardin and 5 more	6 hr
Jan 11, 5:06 AM CST	Mesoscale Discussion	SPC	Fayette, Hardeman, McNairy	54 min

Nearby

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