Alert archive / Georgia / Tornado Watches in 2021

Tornado Watch 571

December 29, 202110 counties in Alabama; 57 counties in Georgia; 4 counties in South Carolina

The Storm Prediction Center issued this tornado watch at Dec 29, 2021, 9:16 PM CST for 10 counties in Alabama; 57 counties in Georgia; 4 counties in South Carolina. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Dec 29, 2021, 9:16 PM CST (03:16 UTC)
Expired
Dec 30, 2021, 4:00 AM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 71 counties

Calhoun County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Randolph County, AL, Shelby County, AL, Talladega County, AL, Tallapoosa County, AL, Banks County, GA, Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Cherokee County, GA, Clarke County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Elbert County, GA, Fannin County, GA, Fayette County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Greene County, GA, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Haralson County, GA, Hart County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Lumpkin County, GA, Madison County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Murray County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Putnam County, GA, Rabun County, GA, Rockdale County, GA, Spalding County, GA, Stephens County, GA, Towns County, GA, Troup County, GA, Union County, GA, Walton County, GA, White County, GA, Whitfield County, GA, Anderson County, SC, Greenville County, SC, Oconee County, SC, Pickens County, SC

The radar

The Atlanta radar (KFFC), 128 km from the middle of the area, began a volume at 03:17 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
50%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
60%
One or more gusts of 65 knots or more
20%
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
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Dec 29, 9:25 PM CSTTornado WarningBMXCalhoun, Cherokee, Cleburne35 min
Dec 29, 9:31 PM CSTSevere Thunderstorm WarningFFCBartow, Cherokee, Cobb, Floyd, Paulding, Polk44 min
Dec 29, 9:37 PM CSTSevere Thunderstorm WarningFFCBartow, Dawson, Gilmer, Gordon, Pickens38 min
Dec 29, 10:01 PM CSTTornado WarningBMXChilton, Shelby32 min
Dec 29, 10:08 PM CSTSevere Thunderstorm WarningFFCBartow, Cherokee, Cobb, Dawson, Forsyth, Fulton and 3 more52 min
Dec 29, 10:12 PM CSTSevere Thunderstorm WarningFFCCarroll, Cobb, Douglas, Haralson, Paulding, Polk48 min
Dec 29, 10:18 PM CSTTornado Warning Tornado observedBMXCoosa, Talladega24 min
Dec 29, 10:39 PM CSTFlash Flood WarningBMXBibb, Chilton, Coosa, Shelby, Talladega2 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 3.3 hours before the alert went out and 123 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, Peachtre/Fal Fld, GA at 00:00Z on 2021-12-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 251 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Peachtre/Fal Fld, GA at 00:00Z on 2021-12-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 228 square meters per square second.19395878Sfc1 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
251 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
790 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
240 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.0

Open this sounding in Storm Lab

The text

As transmitted.

841 
WWUS20 KWNS 300312
SEL1  
SPC WW 300312
ALZ000-GAZ000-NCZ000-SCZ000-301000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 571
NWS Storm Prediction Center Norman OK
1010 PM EST Wed Dec 29 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  East-central Alabama
  Northern Georgia
  Southwest North Carolina
  Northwest South Carolina

* Effective this Wednesday night and Thursday morning from 1010
  PM until 500 AM EST.

* Primary threats include...
  A few tornadoes and a couple intense tornadoes possible
  Scattered damaging wind gusts to 70 mph likely
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...A line of severe thunderstorms will move rapidly east
across the watch area with a risk for damaging winds, a few
tornadoes, and isolated hail. More isolated severe storms may
develop ahead of the line and also pose a risk for a tornado and
damaging wind gusts.

The tornado watch area is approximately along and 70 statute miles
east and west of a line from 55 miles northwest of Anderson SC to 25
miles east of La Grange GA. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU1).

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...CONTINUE...WW 570...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 25040.

...Bunting

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 29, 7:27 PM CSTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 15 more2 hr
Dec 29, 8:44 PM CSTMesoscale DiscussionSPCCalhoun, Cherokee, Etowah2 hr
Dec 29, 10:56 PM CSTMesoscale DiscussionSPCClay, Randolph2 hr
Dec 30, 1:15 AM CSTMesoscale DiscussionSPCBibb, Chambers, Chilton, Clay, Coosa, Randolph and 3 more90 min
Dec 30, 4:02 AM CSTMesoscale DiscussionSPCBibb, Chambers, Chilton, Clay, Coosa, Greene and 10 more2 hr
Dec 30, 10:34 AM CSTMesoscale DiscussionSPCAutauga, Bullock, Chambers, Chilton, Coosa, Dallas and 9 more116 min
Dec 30, 1:05 PM CSTSevere Thunderstorm WatchSPCAutauga, Barbour, Bullock, Butler, Chambers, Clarke and 13 more7 hr
Dec 30, 2:54 PM CSTMesoscale DiscussionSPCBarbour, Bullock, Crenshaw, Lee, Lowndes, Macon and 3 more2 hr
Dec 30, 1:00 PM CSTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 29 more2 hr
Dec 30, 5:35 PM CSTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Ben Hill, Berrien, Brantley and 32 more115 min

Nearby

Tornado Watches in Georgia, 2021Tornado Watches in Alabama, 2021Tornado Watches in South Carolina, 2021Every tornado watch in 2021

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.