Alert archive / Georgia / Mesoscale Discussions in 2021

Mesoscale Discussion 420

April 24, 20215 counties in Alabama; 4 counties in Florida; 25 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2021, 7:29 AM CDT for 5 counties in Alabama; 4 counties in Florida; 25 counties in Georgia. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Apr 24, 2021, 7:29 AM CDT (12:29 UTC)
Expired
Apr 24, 2021, 9:00 AM CDT
In force
91 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 106
All 34 counties

Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Holmes County, FL, Jackson County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Irwin County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Worth County, GA

The radar

The Ft Rucker radar (KEOX), 73 km from the middle of the area, began a volume at 12:31 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 0.5 hours before the alert went out and 99 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, Tallahassee Rgnl, FL at 12:00Z on 2021-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 175 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, Tallahassee Rgnl, FL at 12:00Z on 2021-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 447 square meters per square second.19395878Sfc1 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
175 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
544 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
447 m²/s²
0-3 km storm-relative helicity
570 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

023 
ACUS11 KWNS 241229
SWOMCD
SPC MCD 241229 
GAZ000-FLZ000-ALZ000-241400-

Mesoscale Discussion 0420
NWS Storm Prediction Center Norman OK
0729 AM CDT Sat Apr 24 2021

Areas affected...southeast Alabama into southwest Georgia and parts
of the Florida Panhandle

Concerning...Tornado Watch 106...

Valid 241229Z - 241400Z

The severe weather threat for Tornado Watch 106 continues.

SUMMARY...Damaging gusts or a brief tornado remain possible this
morning, primarily from southeast Alabama into far southwest
Georgia.

DISCUSSION...A southwest-northeast oriented section of a squall line
is currently moving across southeast AL, and will soon move into GA.
Surface analysis shows 65 F +  dewpoints near and south of this
squall line, with drier air currently over much of southern GA and
northern FL. The 12Z TLH sounding shows only a few hundred J/kg
MLCAPE with a 64 F dewpoint, but an impressive hodograph clearly
favorable for supercells given a surface-based effective parcel.

Continued 40-50 kt southwesterly 850 mb flow will aid theta-e
advection this morning ahead of the squall line, which may support a
wind/tornado threat over GA in a few hours. Isolated severe reports
remain possible with the trailing portion of the line into the FL
Panhandle, where dewpoints are in the upper 60s F, but training
echoes may result in undercutting outflow.

..Jewell.. 04/24/2021

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

ATTN...WFO...JAX...FFC...TAE...BMX...MOB...

LAT...LON   30808301 30478616 31288623 31498597 31678588 31928300
            30808301

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 24, 1:00 AM CDTMesoscale DiscussionSPCBaldwin, Coffee, Conecuh, Covington, Escambia, Geneva and 2 more3 hr
Apr 24, 1:00 AM CDTMesoscale DiscussionSPCBaldwin, Coffee, Conecuh, Covington, Escambia, Geneva and 2 more3 hr
Apr 24, 1:23 AM CDTTornado WatchSPCBaldwin, Clarke, Conecuh, Covington, Escambia, Mobile and 2 more8 hr
Apr 24, 3:04 AM CDTMesoscale DiscussionSPCBaldwin, Mobile, Washington116 min
Apr 24, 4:26 AM CDTMesoscale DiscussionSPCConecuh, Covington, Escambia, Monroe, Washington2 hr
Apr 24, 5:22 AM CDTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston9 hr
Apr 24, 12:29 PM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Marengo and 4 more2 hr
Apr 24, 1:17 PM CDTSevere Thunderstorm WatchSPCAutauga, Baldwin, Barbour, Bullock, Butler, Choctaw and 23 more8 hr
Apr 24, 1:22 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Clay, Cleburne, Colbert and 22 more113 min
Apr 24, 3:40 PM CDTMesoscale DiscussionSPCAutauga, Barbour, Bullock, Butler, Clarke, Coffee and 19 more95 min
Apr 24, 4:52 PM CDTSevere Thunderstorm WatchSPCBibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 15 more4 hr
Apr 24, 5:56 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Dale, Henry, Houston and 1 more94 min
Apr 24, 6:13 PM CDTMesoscale DiscussionSPCCalhoun, Chambers, Cherokee, Clay, Cleburne, Coosa and 6 more2 hr
Apr 24, 9:10 AM CDTMesoscale DiscussionSPCNassau95 min
Apr 24, 9:35 AM CDTTornado WatchSPCBaker, Columbia, Duval, Hamilton, Nassau, Suwannee7 hr
Apr 24, 11:05 AM CDTMesoscale DiscussionSPCCalhoun, Gadsden, Holmes, Jackson, Jefferson, Leon and 4 more85 min
Apr 24, 3:35 PM CDTMesoscale DiscussionSPCDuval, Nassau85 min
Apr 24, 3:00 PM CDTSevere Thunderstorm WatchSPCBaker, Berrien, Brooks, Calhoun, Chattahoochee, Clay and 30 more6 hr
Apr 24, 6:47 PM CDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Berrien, Brantley, Bryan and 12 more118 min

Nearby

Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Florida, 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.