Alert archive / Georgia / Mesoscale Discussions in 2021

Mesoscale Discussion 1027

June 19, 20214 counties in Alabama; 15 counties in Florida; 39 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2021, 11:58 PM CDT for 4 counties in Alabama; 15 counties in Florida; 39 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 19, 2021, 11:58 PM CDT (04:58 UTC)
Expired
Jun 20, 2021, 2:00 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Tornado watch 289
All 58 counties

Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Crisp County, GA, Decatur County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Harris County, GA, Irwin County, GA, Lee County, GA, Lowndes County, GA, Macon County, GA, Marion County, GA, Miller County, GA, Mitchell County, GA, Muscogee County, GA, Pulaski County, GA, Randolph County, GA, Schley County, GA, Seminole County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Webster County, GA, Wilcox County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 62 km from the middle of the area, began a volume at 05:01 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 00:00Z, 5.0 hours before the alert went out and 63 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 00:00Z on 2021-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1506 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, Tallahassee Rgnl, FL at 00:00Z on 2021-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 152 square meters per square second.193958Sfc1 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
1506 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
764 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
152 m²/s²
0-3 km storm-relative helicity
223 m²/s²
Significant tornado parameter
0.9
Supercell composite
7.3

Open this sounding in Storm Lab

The text

As transmitted.

828 
ACUS11 KWNS 200458
SWOMCD
SPC MCD 200458 
GAZ000-FLZ000-ALZ000-200700-

Mesoscale Discussion 1027
NWS Storm Prediction Center Norman OK
1158 PM CDT Sat Jun 19 2021

Areas affected...FL Panhandle...extreme southeast AL...southwest GA

Concerning...Tornado Watch 289...

Valid 200458Z - 200700Z

The severe weather threat for Tornado Watch 289 continues.

SUMMARY...The threat for a few tornadoes continues with bands of
showers and thunderstorms associated with Tropical Depression
Claudette.

DISCUSSION...The center of TD Claudette was located over central AL
at 0440z and continues to move northeast at 14 mph. Bands of showers
and occasional thunderstorms were occurring within two confluence
zones in and just west of the watch area, where lower/mid 70s dew
points were contributing to SBCAPE of 1000-1500 J/kg.  Latest VWP
data from KEOX and KTLH sampled 50 kts in the 2-3 km AGL layer, and
low-level SRH of 300-400 m2/s2.  Hi-res guidance continues to
suggest some increase in intensity of convective elements within
bands of showers and thunderstorms during the overnight hours, and
the environment will continue to support the potential for a few
tornadoes.

..Bunting.. 06/20/2021

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

ATTN...WFO...JAX...FFC...TAE...

LAT...LON   30368622 31478594 31668504 32238480 32798504 32758420
            32138331 31728306 30948311 30168344 29758351 29408389
            29338475 29388539 29898617 30368622

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 19, 7:00 PM CDTTornado WatchSPCBarbour, Coffee, Dale, Geneva, Henry, Houston and 2 more13 hr
Jun 20, 5:00 AM CDTMesoscale DiscussionSPCHouston2 hr
Jun 20, 7:40 AM CDTMesoscale DiscussionSPCBaker, Columbia, Duval, Hamilton, Madison, Nassau and 1 more3 hr
Jun 20, 10:01 AM CDTMesoscale DiscussionSPCAlachua, Bradford, Clay119 min

Nearby

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