Alert archive / Tennessee / Tornado Watches in 2015

Tornado Watch 567

December 23, 20158 counties in Alabama; Catoosa County, Dade County, Walker County, Georgia; 30 counties in Tennessee

The Storm Prediction Center issued this tornado watch at Dec 23, 2015, 10:33 PM CST for 8 counties in Alabama; Catoosa County, Dade County, Walker County, Georgia; 30 counties in Tennessee. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Dec 23, 2015, 10:33 PM CST (04:33 UTC)
Expired
Dec 24, 2015, 3:18 AM CST
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 41 counties

Cullman County, AL, DeKalb County, AL, Jackson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Catoosa County, GA, Dade County, GA, Walker County, GA, Bedford County, TN, Bledsoe 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, Marion County, TN, Marshall 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, Van Buren County, TN, Warren County, TN, White County, TN

The radar

The Northeast Alabama radar (KHTX), 96 km from the middle of the area, began a volume at 04:36 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Dec 23, 10:50 PM CSTSevere Thunderstorm WarningOHXClay, Fentress, Overton, Pickett25 min
Dec 23, 11:01 PM CSTSevere Thunderstorm WarningOHXDeKalb, Overton, Putnam, White29 min
Dec 23, 11:13 PM CSTSevere Thunderstorm WarningOHXFentress, Overton, Pickett32 min
Dec 24, 1:20 AM CSTSevere Thunderstorm WarningHUNDeKalb, Jackson25 min
Dec 24, 1:53 AM CSTSevere Thunderstorm WarningFFCCatoosa, Walker, Whitfield37 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, 4.6 hours before the alert went out and 94 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 2015-12-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 joules per kilogram.LCLLFCEL10008507005003002001001 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 2015-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 598 square meters per square second.1939587897117Sfc1 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
26 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
624 m above ground
0-6 km bulk shear
89 kt
0-1 km storm-relative helicity
598 m²/s²
0-3 km storm-relative helicity
698 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

442 
WWUS20 KWNS 240431
SEL7  
SPC WW 240431
ALZ000-GAZ000-TNZ000-241000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 567
NWS STORM PREDICTION CENTER NORMAN OK
1035 PM CST WED DEC 23 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  NORTHEAST ALABAMA
  EXTREME NORTHWEST GEORGIA
  PARTS OF MIDDLE AND EASTERN TENNESSEE

* EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1035
  PM UNTIL 400 AM CST.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

SUMMARY...BROKEN BANDS OF STRONG/SEVERE STORMS WILL PERSIST INTO THE
EARLY MORNING HOURS FROM NORTH CENTRAL AND NORTHEAST ALABAMA INTO
PARTS OF MIDDLE/EASTERN TENNESSEE AND EXTREME NORTHWEST GEORGIA. 
THE STORM ENVIRONMENT WILL REMAIN FAVORABLE FOR ROTATING STORMS
CAPABLE OF PRODUCING A COUPLE OF TORNADOES...DAMAGING GUSTS...AND
SOME HAIL.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH NORTHEAST OF
CROSSVILLE TENNESSEE TO 20 MILES SOUTH SOUTHEAST OF HUNTSVILLE
ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 564. WATCH NUMBER 564 WILL NOT BE IN EFFECT AFTER
1035 PM CST. CONTINUE...WW 565...WW 566...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 24045.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 23, 6:35 PM CSTMesoscale DiscussionSPCColbert, Franklin, Lauderdale, Lawrence, Limestone, Madison and 1 more55 min
Dec 23, 7:41 PM CSTMesoscale DiscussionSPCBibb, Fayette, Greene, Hale, Jefferson, Lamar and 8 more2 hr
Dec 23, 8:20 PM CSTTornado WatchSPCBibb, Fayette, Greene, Hale, Jefferson, Lamar and 7 more8 hr
Dec 23, 10:11 PM CSTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Cullman, DeKalb, Etowah and 12 more2 hr
Dec 24, 3:10 AM CSTMesoscale DiscussionSPCAutauga, Barbour, Bullock, Butler, Chambers, Coffee and 19 more2 hr
Dec 24, 3:27 AM CSTMesoscale DiscussionSPCBibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 16 more93 min
Dec 24, 4:09 AM CSTTornado WatchSPCBarbour, Bullock, Coffee, Dale, Geneva, Henry and 5 more7 hr
Dec 24, 7:07 AM CSTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Covington, Dale, Henry and 2 more83 min
Dec 23, 7:42 PM CSTMesoscale DiscussionSPCPickett2 hr

Nearby

Tornado Watches in Tennessee, 2015Tornado Watches in Alabama, 2015Tornado Watches in Georgia, 2015Every tornado 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.