Alert archive / Georgia / Mesoscale Discussions in 2021

Mesoscale Discussion 2022

December 11, 202116 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 11, 2021, 5:32 PM EST for 16 counties in Georgia. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Dec 11, 2021, 5:32 PM EST (22:32 UTC)
Expired
Dec 11, 2021, 7:00 PM EST
In force
88 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Bleckley County, GA, Burke County, GA, Columbia County, GA, Emanuel County, GA, Glascock County, GA, Houston County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Laurens County, GA, McDuffie County, GA, Richmond County, GA, Treutlen County, GA, Twiggs County, GA, Washington County, GA, Wilkinson County, GA

The radar

The Robins AFB radar (KJGX), 66 km from the middle of the area, began a volume at 22:33 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, 10.5 hours before the alert went out and 176 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 12:00Z on 2021-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 182 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, Peachtre/Fal Fld, GA at 12:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 268 square meters per square second.1939587897Sfc1 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
182 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
625 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
268 m²/s²
0-3 km storm-relative helicity
271 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

891 
ACUS11 KWNS 112233
SWOMCD
SPC MCD 112232 
SCZ000-GAZ000-120000-

Mesoscale Discussion 2022
NWS Storm Prediction Center Norman OK
0432 PM CST Sat Dec 11 2021

Areas affected...Portions of eastern Georgia

Concerning...Severe potential...Watch unlikely 

Valid 112232Z - 120000Z

Probability of Watch Issuance...5 percent

SUMMARY...A brief damaging wind/tornado threat exists for the next 1
to 2 hours across eastern Georgia.

DISCUSSION...A few mini supercells have developed ahead of a line of
storms moving through eastern Georgia. One of these mini supercells
in Wilkinson county had a TDS for around 5 minutes starting around
2219Z. 0 to 1 km SRH around 150 to 200 m2/s2 at the KJGX VWP shows a
low-level shear environment favorable for a brief tornado threat to
continue. Therefore, this storm, and any additional supercells which
can develop ahead of the line, will pose a threat for a brief
tornado before the main squall line eventually overtakes these
storms.

..Bentley/Grams.. 12/11/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CHS...CAE...FFC...

LAT...LON   33118314 33428264 33588227 33388194 32958169 32508214
            32258286 32248336 32408380 33118314

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 11, 8:34 AM ESTMesoscale DiscussionSPCBartow, Catoosa, Chattooga, Floyd, Gordon, Haralson and 3 more86 min
Dec 11, 11:47 AM ESTMesoscale DiscussionSPCCarroll, Coweta, Fayette, Harris, Heard, Meriwether and 1 more118 min

Nearby

Mesoscale Discussions in Georgia, 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.