Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 2083
The Storm Prediction Center issued this mesoscale discussion at Dec 30, 2021, 1:15 AM CST for 9 counties in Alabama; 21 counties in Georgia; McCormick County, Newberry County, Saluda County, South Carolina. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Dec 30, 2021, 1:15 AM CST (07:15 UTC)
- Expired
- Dec 30, 2021, 2:45 AM CST
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 571
All 33 counties
Bibb County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Coosa County, AL, Randolph County, AL, Shelby County, AL, Talladega County, AL, Tallapoosa County, AL, Butts County, GA, Clayton County, GA, Coweta County, GA, Fayette County, GA, Greene County, GA, Heard County, GA, Henry County, GA, Jasper County, GA, Lamar County, GA, Lincoln County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Newton County, GA, Pike County, GA, Putnam County, GA, Rockdale County, GA, Spalding County, GA, Taliaferro County, GA, Troup County, GA, Wilkes County, GA, McCormick County, SC, Newberry County, SC, Saluda County, SC
The radar
The Atlanta radar (KFFC), 47 km from the middle of the area, began a volume at 07:18 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 nearest sounding before it
Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 7.3 hours before the alert went out and 53 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.
283
ACUS11 KWNS 300716
SWOMCD
SPC MCD 300715
SCZ000-GAZ000-ALZ000-300845-
Mesoscale Discussion 2083
NWS Storm Prediction Center Norman OK
0115 AM CST Thu Dec 30 2021
Areas affected...Portions of central AL into central/eastern GA and
far west-central SC
Concerning...Tornado Watch 571...
Valid 300715Z - 300845Z
The severe weather threat for Tornado Watch 571 continues.
SUMMARY...An isolated severe threat continues in/near Tornado Watch
571. Downstream watch issuance into more of eastern Georgia and
central South Carolina appears unlikely at this time.
DISCUSSION...A broken line of convection extends from parts of
central AL into GA and upstate SC early this morning. The leading
portion of the line now moving into central SC has shown a general
weakening trend over the past couple of hours. A less unstable
airmass with more convective inhibition noted in latest mesoanalysis
estimates may continue to limit the severe potential in the short
term across SC. Therefore, downstream watch issuance into more of
eastern GA and central SC appears unlikely at this time.
Farther west into central AL/GA, the ongoing broken line is oriented
largely parallel to the deep-layer shear vectors. The low-level flow
has also largely veered to a west-southwesterly component based on
recent VWPs for KBMX/KMXX/KFFC. This is limiting directional shear
and 0-1-km SRH, but effective bulk shear of 45-50 kt is still
present. This shear can still support supercells, although the
current storm mode appears rather messy at the moment. The moist
low-level airmass and related 500-1000 J/kg of MLCAPE present should
also be sufficient to support surface-based storms along/south of
the ongoing activity. An isolated threat for damaging winds and
perhaps a tornado continues in/near Tornado Watch 571. But, it does
appear that the overall severe threat may be gradually diminishing.
..Gleason.. 12/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CAE...GSP...FFC...BMX...
LAT...LON 33248695 33498608 33698387 34048207 34398148 34188124
33058351 32698679 32728722 32948738 33118730 33248695SPC 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, 8:44 PM CST | Mesoscale Discussion | SPC | Calhoun, Cherokee, Etowah | 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, 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 Alabama, 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.