Alert archive / Georgia / Mesoscale Discussions in 2019

Mesoscale Discussion 2221

December 17, 20199 counties in Alabama; Holmes County, Santa Rosa County, Florida; 24 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 17, 2019, 2:13 AM CST for 9 counties in Alabama; Holmes County, Santa Rosa County, Florida; 24 counties in Georgia. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Dec 17, 2019, 2:13 AM CST (08:13 UTC)
Expired
Dec 17, 2019, 3:45 AM CST
In force
92 min
Issued by
the Storm Prediction Center
All 35 counties

Barbour County, AL, Coffee County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Pike County, AL, Holmes County, FL, Santa Rosa County, FL, Bibb County, GA, Bleckley County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Crawford County, GA, Dooly County, GA, Early County, GA, Houston County, GA, Jones County, GA, Lee County, GA, Macon County, GA, Marion County, GA, Peach County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Stewart County, GA, Sumter County, GA, Taylor County, GA, Terrell County, GA, Twiggs County, GA, Webster County, GA

The radar

The Ft Rucker radar (KEOX), 43 km from the middle of the area, began a volume at 08:12 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, 8.2 hours before the alert went out and 190 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 2019-12-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 15 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 00:00Z on 2019-12-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 272 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
15 J/kg
Mixed-layer CIN
-120 J/kg
Mixed-layer LCL
864 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
272 m²/s²
0-3 km storm-relative helicity
353 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

827 
ACUS11 KWNS 170814
SWOMCD
SPC MCD 170813 
GAZ000-FLZ000-ALZ000-170945-

Mesoscale Discussion 2221
NWS Storm Prediction Center Norman OK
0213 AM CST Tue Dec 17 2019

Areas affected...southern Alabama...central and southwest Georgia
and the western Florida Panhandle

Concerning...Tornado Watch 703...

Valid 170813Z - 170945Z

The severe weather threat for Tornado Watch 703 continues.

SUMMARY...The severe threat across the remainder of WW 703 is
becoming increasingly marginal. South of the WW from southern
Alabama into southwest Georgia and the western FL panhandle, some
threat for isolated damaging wind and a brief tornado will persist
into the early morning. Trends are being monitored for a possible WW
south of WW 703.

DISCUSSION...An expansive squall line extends from central GA
southwest into southern AL and southeast MS. While a threat for
isolated damaging wind and a brief tornado persists, most of the
line has become oriented parallel to the deep layer winds and storms
are generally poorly organized. 

Other storms have developed in a pre-frontal warm sector along the
warm conveyor belt from the western FL Panhandle into southeast AL
and southwest GA. These storms are in an environment with richer
low-level moisture (upper 60s F dewpoints) which indicate updrafts
are close to surface based. Given the presence of strong vertical
shear and 200-300 m2/s2 0-1 km storm relative helicity, a
conditional threat exists for isolated damaging wind and a tornado
or two.

..Dial.. 12/17/2019

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

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

LAT...LON   31488685 31888608 32208509 32718416 33248349 32368326
            30728550 30558740 31488685

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 16, 6:05 PM CSTMesoscale DiscussionSPCCherokee, DeKalb, Etowah, Jackson, Madison, Marshall55 min
Dec 16, 6:12 PM CSTMesoscale DiscussionSPCSumter2 hr
Dec 16, 7:57 PM CSTMesoscale DiscussionSPCChoctaw, Dallas, Hale, Marengo, Perry, Sumter93 min
Dec 16, 8:58 PM CSTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 19 more92 min
Dec 16, 9:47 PM CSTTornado WatchSPCAutauga, Bibb, Blount, Butler, Calhoun, Chambers and 24 more6 hr
Dec 17, 6:54 AM CSTTornado WatchSPCHenry, Houston7 hr
Dec 17, 9:29 AM CSTMesoscale DiscussionSPCBay, Calhoun, Gadsden, Jackson, Jefferson, Leon and 1 more91 min
Dec 17, 10:32 AM CSTMesoscale DiscussionSPCBaker, Columbia, Hamilton, Lafayette, Madison, Nassau and 2 more88 min
Dec 17, 10:58 AM CSTTornado WatchSPCBaker, Columbia, Hamilton, Nassau, Suwannee5 hr
Dec 17, 1:58 PM CSTMesoscale DiscussionSPCBaker, Columbia, Duval, Hamilton, Lafayette, Nassau and 2 more92 min
Dec 17, 2:04 PM CSTMesoscale DiscussionSPCBrevard, Citrus, DeSoto, Flagler, Hardee, Hernando and 15 more116 min
Dec 16, 11:11 PM CSTMesoscale DiscussionSPCCarroll, Chattahoochee, Clayton, Coweta, DeKalb, Douglas and 16 more64 min

Nearby

Mesoscale Discussions in Georgia, 2019Mesoscale Discussions in Alabama, 2019Mesoscale Discussions in Florida, 2019Every mesoscale discussion in 2019

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.