Alert archive / Tennessee / Severe Thunderstorm Watches in 2016
Severe Thunderstorm Watch 519
The Storm Prediction Center issued this severe thunderstorm watch at Dec 18, 2016, 1:03 AM CST for 13 counties in Alabama; 30 counties in Tennessee. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 18, 2016, 1:03 AM CST (07:03 UTC)
- Expired
- Dec 18, 2016, 5:00 AM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 43 counties
Blount County, AL, Cullman County, AL, DeKalb County, AL, Fayette County, AL, Jackson County, AL, Lamar County, AL, Lawrence County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Anderson County, TN, Bledsoe County, TN, Bradley County, TN, Campbell County, TN, Cannon County, TN, Claiborne County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Franklin County, TN, Grundy County, TN, Hamilton County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, White County, TN
The radar
The Northeast Alabama radar (KHTX), 60 km from the middle of the area, began a volume at 07:03 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.
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
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 18, 1:06 AM CST | Severe Thunderstorm Warning | HUN | Limestone, Madison | 24 min |
| Dec 18, 1:14 AM CST | Severe Thunderstorm Warning | HUN | Colbert, Franklin, Lawrence | 31 min |
| Dec 18, 1:20 AM CST | Tornado Warning | OHX | Bedford, Cannon, Coffee, Warren | 25 min |
| Dec 18, 1:30 AM CST | Severe Thunderstorm Warning | HUN | Limestone, Madison | 45 min |
| Dec 18, 1:30 AM CST | Severe Thunderstorm Warning | MRX | Scott | 30 min |
| Dec 18, 1:42 AM CST | Severe Thunderstorm Warning | OHX | Coffee, Van Buren, Warren, White | 33 min |
| Dec 18, 1:48 AM CST | Severe Thunderstorm Warning | HUN | Limestone, Madison, Morgan | 27 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, 7.1 hours before the alert went out and 100 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
- 26 J/kg
- Mixed-layer CIN
- -109 J/kg
- Mixed-layer LCL
- 692 m above ground
- 0-6 km bulk shear
- 81 kt
- 0-1 km storm-relative helicity
- 511 m²/s²
- 0-3 km storm-relative helicity
- 473 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 17, 8:28 PM CST | Mesoscale Discussion | SPC | Colbert, Franklin, Lauderdale, Lawrence, Limestone, Marion | 62 min |
| Dec 17, 8:58 PM CST | Tornado Watch | SPC | Colbert, Franklin, Lauderdale, Lawrence, Limestone | 6 hr |
| Dec 17, 11:48 PM CST | Mesoscale Discussion | SPC | Colbert, Franklin, Lamar, Lauderdale, Lawrence, Limestone and 1 more | 87 min |
| Dec 18, 2:30 AM CST | Mesoscale Discussion | SPC | Colbert, Lauderdale | 4 hr |
| Dec 18, 3:24 AM CST | Mesoscale Discussion | SPC | Blount, Cullman, DeKalb, Etowah, Jackson, Marshall and 1 more | 66 min |
Nearby
Severe Thunderstorm Watches in Tennessee, 2016Severe Thunderstorm Watches in Alabama, 2016Every severe thunderstorm watch in 2016
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.