Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 2081
The Storm Prediction Center issued this mesoscale discussion at Dec 29, 2021, 8:44 PM CST for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 29, 2021, 8:44 PM CST (02:44 UTC)
- Expired
- Dec 29, 2021, 10:45 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 54 counties
Calhoun County, AL, Cherokee County, AL, Etowah County, AL, Banks County, GA, Barrow County, GA, Bartow County, GA, Chattooga County, GA, Cherokee County, GA, Clarke County, GA, Cobb County, GA, Dawson County, GA, Elbert County, GA, Fannin County, GA, Floyd County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Haralson County, GA, Hart County, GA, Jackson County, GA, Lumpkin County, GA, Madison County, GA, Murray County, GA, Paulding County, GA, Pickens County, GA, Polk County, GA, Rabun County, GA, Stephens County, GA, Towns County, GA, Union County, GA, White County, GA, Whitfield County, GA, Buncombe County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, Polk County, NC, Transylvania County, NC, Abbeville County, SC, Anderson County, SC, Greenville County, SC, Laurens County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Polk County, TN
The radar
The Atlanta radar (KFFC), 130 km from the middle of the area, began a volume at 02:46 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 2.7 hours before the alert went out and 128 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
- 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
The text
As transmitted.
501
ACUS11 KWNS 300245
SWOMCD
SPC MCD 300244
SCZ000-NCZ000-GAZ000-TNZ000-ALZ000-300445-
Mesoscale Discussion 2081
NWS Storm Prediction Center Norman OK
0844 PM CST Wed Dec 29 2021
Areas affected...northern Georgia into the far western Carolinas
Concerning...Severe potential...Watch likely
Valid 300244Z - 300445Z
Probability of Watch Issuance...80 percent
SUMMARY...Storms moving out of Tennessee and Alabama may continue to
pose a damaging wind and brief tornado threat.
DISCUSSION...A long-lived line of storms currently extends from far
eastern TN into northeast AL, with QLCS structures observed on radar
with a brief tornado possibly occurring in DeKalb County AL.
Surface analysis shows mid 60s F dewpoints have spread into the
Atlanta area, with low 60s F approaching western NC. This is
resulting in sufficient SBCAPE to sustain a damaging wind and
tornado risk, as shear remains strong. 0-1 SRH of 250-300 m2/s2
currently resides ahead of the line of storms, and strongly favors
low-level rotation. As such, the QLCS tornado and wind risk is
expected to continue eastward, and a new watch may be necessary
soon.
..Jewell/Bunting.. 12/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GSP...MRX...FFC...BMX...HUN...
LAT...LON 33908633 34188610 34408582 34728506 35098466 35288429
35638261 35528213 35308191 34898184 34448193 34058256
33808390 33788451 33738547 33788614 33908633SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 29, 7:27 PM CST | Mesoscale Discussion | SPC | Bibb, Blount, Calhoun, Cherokee, Chilton, Clay and 15 more | 2 hr |
| Dec 29, 9:16 PM CST | Tornado Watch | SPC | Calhoun, Chambers, Chilton, Clay, Cleburne, Coosa and 4 more | 7 hr |
| Dec 29, 10:56 PM CST | Mesoscale Discussion | SPC | Clay, Randolph | 2 hr |
| Dec 30, 1:15 AM CST | Mesoscale Discussion | SPC | Bibb, Chambers, Chilton, Clay, Coosa, Randolph and 3 more | 90 min |
| Dec 30, 4:02 AM CST | Mesoscale Discussion | SPC | Bibb, Chambers, Chilton, Clay, Coosa, Greene and 10 more | 2 hr |
| Dec 30, 10:34 AM CST | Mesoscale Discussion | SPC | Autauga, Bullock, Chambers, Chilton, Coosa, Dallas and 9 more | 116 min |
| Dec 30, 1:05 PM CST | Severe Thunderstorm Watch | SPC | Autauga, Barbour, Bullock, Butler, Chambers, Clarke and 13 more | 7 hr |
| Dec 30, 2:54 PM CST | Mesoscale Discussion | SPC | Barbour, Bullock, Crenshaw, Lee, Lowndes, Macon and 3 more | 2 hr |
| Dec 30, 1:00 PM CST | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 29 more | 2 hr |
| Dec 30, 5:35 PM CST | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Ben Hill, Berrien, Brantley and 32 more | 115 min |
Nearby
Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in North Carolina, 2021Mesoscale Discussions in South Carolina, 2021Every mesoscale discussion 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.