Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 2087
The Storm Prediction Center issued this mesoscale discussion at Dec 30, 2021, 2:54 PM CST for 9 counties in Alabama; 42 counties in Georgia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 30, 2021, 2:54 PM CST (20:54 UTC)
- Expired
- Dec 30, 2021, 5:00 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 572
All 51 counties
Barbour County, AL, Bullock County, AL, Crenshaw County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Baldwin County, GA, Bibb County, GA, Bleckley County, GA, Candler County, GA, Chattahoochee County, GA, Crawford County, GA, Crisp County, GA, Dodge County, GA, Dooly County, GA, Emanuel County, GA, Harris County, GA, Houston County, GA, Jefferson County, GA, Johnson County, GA, Jones County, GA, Laurens County, GA, Lee County, GA, Macon County, GA, Marion County, GA, Monroe County, GA, Montgomery County, GA, Muscogee County, GA, Peach County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Telfair County, GA, Terrell County, GA, Toombs County, GA, Treutlen County, GA, Twiggs County, GA, Upson County, GA, Washington County, GA, Webster County, GA, Wheeler County, GA, Wilcox County, GA, Wilkinson County, GA
The radar
The Robins AFB radar (KJGX), 94 km from the middle of the area, began a volume at 20:53 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 12:00Z, 8.9 hours before the alert went out and 115 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
- 408 J/kg
- Mixed-layer CIN
- -26 J/kg
- Mixed-layer LCL
- 451 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 342 m²/s²
- 0-3 km storm-relative helicity
- 348 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.1
The text
As transmitted.
088
ACUS11 KWNS 302055
SWOMCD
SPC MCD 302054
GAZ000-ALZ000-302300-
Mesoscale Discussion 2087
NWS Storm Prediction Center Norman OK
0254 PM CST Thu Dec 30 2021
Areas affected...portions of south-central Alabama...and central
Georgia
Concerning...Severe Thunderstorm Watch 572...
Valid 302054Z - 302300Z
The severe weather threat for Severe Thunderstorm Watch 572
continues.
SUMMARY...Thunderstorms will continue to intensify across WW 572
this afternoon. Damaging wind gusts, large hail, and a couple of
tornadoes are possible.
DISCUSSION...A band of semi-discrete supercell clusters will
continue spreading generally eastward across parts of east-central
AL and central GA over the next several hours. Within the
pre-convective environment, moist south-southwesterly trajectories
(upper 60s/lower 70s dewpoints) off the eastern Gulf of Mexico
combined with diurnally steepening low-level lapse rates are
resulting in favorable surface-based inflow. Generally weak forcing
for ascent across the area combined with deep-layer shear vectors
oriented obliquely to the low-level axis of forcing should support
the maintenance of separated updrafts. Ahead of the ongoing
convection, the latest RAP mesoanalysis and VWPs show effective SRH
values of 150-180 m2/s2 and 0-6 km bulk shear of 50-60 knots. These
factors will continue to support the risk of semi-discrete supercell
structures capable of producing large hail, damaging wind gusts, and
a couple of tornadoes. The tornado risk may eventually become
maximized over portions of south-central GA, where surface winds
should remain slightly more backed beneath a strengthening 850-mb
low-level jet.
..Weinman.. 12/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CHS...CAE...JAX...FFC...TAE...BMX...MOB...
LAT...LON 31528622 31868678 32358662 32628594 33008461 33168335
33208245 32868207 32348206 32008225 31818278 31528622SPC 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, 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, 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, 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.