Alert archive / Tennessee / Mesoscale Discussions in 2017
Mesoscale Discussion 304
The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2017, 4:30 PM CDT for Jackson County, Alabama; 4 counties in Georgia; 22 counties in Tennessee. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Mar 21, 2017, 4:30 PM CDT (21:30 UTC)
- Expired
- Mar 21, 2017, 6:00 PM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
All 27 counties
Jackson County, AL, Catoosa County, GA, Dade County, GA, Walker County, GA, Whitfield County, GA, Bedford County, TN, Bledsoe County, TN, Bradley County, TN, Cannon County, TN, Coffee County, TN, DeKalb County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Lincoln County, TN, Marion County, TN, Marshall County, TN, Meigs County, TN, Moore County, TN, Rhea County, TN, Rutherford County, TN, Sequatchie County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Wilson County, TN
The radar
The Northeast Alabama radar (KHTX), 37 km from the middle of the area, began a volume at 21:33 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 12:00Z, 9.5 hours before the alert went out and 124 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.
- Mixed-layer CAPE
- 215 J/kg
- Mixed-layer CIN
- -332 J/kg
- Mixed-layer LCL
- 1125 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 157 m²/s²
- 0-3 km storm-relative helicity
- 207 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 21, 1:53 PM CDT | Mesoscale Discussion | SPC | Calhoun, Cherokee, Cleburne, Colbert, DeKalb, Etowah and 7 more | 3 hr |
| Mar 21, 2:33 PM CDT | Severe Thunderstorm Watch | SPC | Cherokee, DeKalb, Jackson, Lauderdale, Limestone, Madison and 1 more | 7 hr |
| Mar 21, 6:47 PM CDT | Mesoscale Discussion | SPC | Burke, Clarke, Columbia, Elbert, Glascock, Greene and 17 more | 58 min |
Nearby
Mesoscale Discussions in Tennessee, 2017Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Alabama, 2017Every mesoscale discussion in 2017
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.