Alert archive / Georgia / Mesoscale Discussions in 2021

Mesoscale Discussion 430

April 24, 2021Chambers County, Lee County, Alabama; 38 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2021, 8:02 PM CDT for Chambers County, Lee County, Alabama; 38 counties in Georgia. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued
Apr 24, 2021, 8:02 PM CDT (01:02 UTC)
Expired
Apr 24, 2021, 9:00 PM CDT
In force
58 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 110
All 40 counties

Chambers County, AL, Lee County, AL, Baldwin County, GA, Bibb County, GA, Butts County, GA, Carroll County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Crawford County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Fulton County, GA, Greene County, GA, Hancock County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Muscogee County, GA, Newton County, GA, Peach County, GA, Pike County, GA, Putnam County, GA, Rockdale County, GA, Spalding County, GA, Talbot County, GA, Taylor County, GA, Troup County, GA, Twiggs County, GA, Upson County, GA, Walton County, GA, Washington County, GA, Wilkinson County, GA

The radar

The Atlanta radar (KFFC), 47 km from the middle of the area, began a volume at 01:06 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, 1.0 hours before the alert went out and 44 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 2021-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 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 2021-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 175 square meters per square second.1939587897117Sfc1 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
72 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
1188 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
175 m²/s²
0-3 km storm-relative helicity
168 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

263 
ACUS11 KWNS 250103
SWOMCD
SPC MCD 250102 
GAZ000-ALZ000-250200-

Mesoscale Discussion 0430
NWS Storm Prediction Center Norman OK
0802 PM CDT Sat Apr 24 2021

Areas affected...West-central Georgia

Concerning...Severe Thunderstorm Watch 110...

Valid 250102Z - 250200Z

The severe weather threat for Severe Thunderstorm Watch 110
continues.

SUMMARY...Sporadic wind damage will remain possible with a line of
thunderstorms moving across central Georgia. A gradual weakening
trend is expected as this line moves eastward after 10 PM EDT.

DISCUSSION...The line of clustered supercells has consolidated into
a squall line as it moves across western GA. Although the hail
threat has greatly diminished with these storms, sporadic wind
damage reports have been noted into the Atlanta metro, including a
76 mph report from ATL. Wind damage will remain possible with this
line in the near term thanks to strong 50 knot flow within the
lowest 2 km (per KFFC VWP obs). However, the 00 UTC FFC sounding
shows limited instability, and the onset of diurnal cooling along
with residual cold pool air across central GA are further limiting
factors for this line as it continues east. Recent IR imagery shows
warming cloud tops, suggesting that gradual weakening is already
underway. This trend will likely continue through 10 PM EDT, and
Watch 110 will likely be allowed to expire.

..Moore.. 04/25/2021

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

ATTN...WFO...FFC...BMX...

LAT...LON   32968575 33598520 33988451 33928367 33668306 33378268
            33088257 32778276 32548324 32458395 32478463 32558526
            32758562 32968575

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 24, 7:48 PM CDTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston4 hr
Apr 24, 10:42 PM CDTMesoscale DiscussionSPCBrantley, Brooks, Clinch, Echols, Glynn, Lanier and 3 more93 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.