Alert archive / Tennessee / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 85
The Storm Prediction Center issued this severe thunderstorm watch at Apr 20, 2015, 1:09 AM CDT for 16 counties in Alabama; 7 counties in Georgia; 41 counties in Tennessee. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2015, 1:09 AM CDT (06:09 UTC)
- Expired
- Apr 20, 2015, 4:59 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 64 counties
Blount County, AL, Cherokee County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Jackson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Floyd County, GA, Gordon County, GA, Walker County, GA, Whitfield County, GA, Anderson County, TN, Bedford County, TN, Bledsoe County, TN, Bradley County, TN, Campbell County, TN, Cannon County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Jackson County, TN, Lincoln County, TN, Macon County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, McMinn County, TN, Meigs County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Rutherford County, TN, Scott County, TN, Sequatchie County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN, Wilson County, TN
The radar
The Northeast Alabama radar (KHTX), 35 km from the middle of the area, began a volume at 06:12 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 1:16 AM CDT | Severe Thunderstorm Warning | BMX | Walker, Winston | 59 min |
| Apr 20, 1:28 AM CDT | Severe Thunderstorm Warning | HUN | Limestone, Madison, Morgan | 62 min |
| Apr 20, 1:29 AM CDT | Severe Thunderstorm Warning | OHX | Macon, Smith, Sumner, Trousdale, Wilson | 31 min |
| Apr 20, 1:42 AM CDT | Severe Thunderstorm Warning | HUN | Lincoln, Moore | 48 min |
| Apr 20, 1:54 AM CDT | Severe Thunderstorm Warning | HUN | Cullman | 51 min |
| Apr 20, 2:05 AM CDT | Severe Thunderstorm Warning | HUN | Jackson, Madison, Marshall | 55 min |
| Apr 20, 2:15 AM CDT | Severe Thunderstorm Warning | HUN | Franklin | 45 min |
| Apr 20, 2:19 AM CDT | Severe Thunderstorm Warning | OHX | Clay, Jackson, Overton, Pickett | 41 min |
| Apr 20, 2:23 AM CDT | Severe Thunderstorm Warning | HUN | Marshall | 40 min |
| Apr 20, 2:32 AM CDT | Severe Thunderstorm Warning | BMX | Blount | 13 min |
| Apr 20, 2:44 AM CDT | Severe Thunderstorm Warning | MRX | Bledsoe, Hamilton, Marion, Sequatchie | 46 min |
| Apr 20, 2:54 AM CDT | Severe Thunderstorm Warning | HUN | DeKalb, Jackson | 55 min |
| Apr 20, 2:57 AM CDT | Severe Thunderstorm Warning | FFC | Catoosa, Chattooga, Dade, Floyd, Walker | 48 min |
| Apr 20, 4:30 AM CDT | Severe Thunderstorm Warning | FFC | Gilmer, Gordon, Murray | 30 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Nashville Metro, TN (KBNA), launched 00:00Z, 6.2 hours before the alert went out and 138 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
- 170 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 927 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.7
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 12:45 AM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 8 more | 90 min |
| Apr 20, 2:36 AM CDT | Mesoscale Discussion | SPC | Blount, Cherokee, DeKalb, Etowah, Jackson, Madison and 1 more | 84 min |
| Apr 20, 10:04 AM CDT | Severe Thunderstorm Watch | SPC | Appling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 25 more | 8 hr |
| Apr 20, 12:03 PM CDT | Mesoscale Discussion | SPC | Banks, Clarke, Elbert, Franklin, Habersham, Hall and 7 more | 57 min |
| Apr 20, 12:23 PM CDT | Tornado Watch | SPC | Banks, Barrow, Clarke, Clayton, Cobb, Coweta and 22 more | 7 hr |
| Apr 20, 3:18 PM CDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, Elbert, Franklin, Habersham and 9 more | 57 min |
| Apr 20, 3:36 PM CDT | Tornado Watch | SPC | Lincoln | 5 hr |
| Apr 20, 5:45 PM CDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, DeKalb, Elbert, Forsyth and 17 more | 60 min |
| Apr 19, 8:02 PM CDT | Tornado Watch | SPC | Benton, Carroll, Chester, Crockett, Decatur, Dyer and 15 more | 5 hr |
| Apr 19, 8:21 PM CDT | Mesoscale Discussion | SPC | Lake | 54 min |
| Apr 19, 10:16 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Chester, Crockett, Dyer, Fayette and 13 more | 59 min |
Nearby
Severe Thunderstorm Watches in Tennessee, 2015Severe Thunderstorm Watches in Alabama, 2015Severe Thunderstorm Watches in Georgia, 2015Every severe thunderstorm watch in 2015
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.