241
FXUS62 KFFC 190252
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
1052 PM EDT Sat May 18 2024

.UPDATE...
Issued at 1047 PM EDT Sat May 18 2024

Convection continues to wind down this evening, with a few lingering
thunderstorms over the NE and SW corners of the County Warning Area.
A shortwave will move SE across the area later tonight and Sun
morning, with more shower activity possible. The forecast remains on
track. /SEC


&&

.SHORT TERM...
(This afternoon through Sunday)
Issued at 210 PM EDT Sat May 18 2024

Water vapor satellite imagery and radar imagery depict the fetch of
moisture and embedded convection that brought moderate to heavy
rainfall across portions of central GA shifting south and east.
Isolated to scattered showers have begun to develop north of this
area that was worked over by earlier rainfall, as cloud cover has
begun to scatter out. SBCAPE has climbed to 1500-2000 J/kg across
much of the CWA, so expect to see increasing coverage of showers as
the afternoon continues. A shortwave/concentrated area of vorticity
currently over TN/AL is tracking eastward, so also expect to see
scattered to widespread thunderstorms develop across north GA over
the next several hours. Some storms over N AL associated with this
feature have been strong to severe, so expect that some storms across
north GA will have similar intensity. The primary threats will be
damaging wind gusts and hail up to 1" in diameter, with cloud-to-
ground lightning and heavy rainfall also concerns. As this feature
aloft draws closer and insolation increases across the rest of the
CWA (at least where cloud cover clears out enough), the potential for
isolated strong to severe storms farther south will increase. SPC
has the entire CWA in a Marginal Risk, which makes sense given the
ample bulk shear from a belt of strong winds aloft plus the
shortwave, as well as increasing diurnally-driven instability.

Some of the CAMs suggest that convection could organize into
lines/clusters late this afternoon into the evening due to the
forcing aloft and convergence of outflow boundaries. As a result,
some showers and storms could persist well after sunset, but in
general, expect to see an overall decrease in coverage of convection
as daytime heating ceases. The aforementioned shortwave axis will
shift east of the CWA tomorrow (Sunday), but progged SBCAPE/MUCAPE of
500-1500 J/kg area-wide will support isolated to scattered showers
and thunderstorms in the afternoon and early evening. A strong storm
or two with gusty winds will be possible, but with little to no bulk
shear and poor mid-level lapse rates expected, severe storms look to
be unlikely. SPC has the entire CWA in General Thunder tomorrow.

Martin

&&

.LONG TERM...
(Monday morning through next Friday)
Issued at 210 PM EDT Sat May 18 2024

No major weather impacts or forecast concerns expected in the long
term period.

Positively tilted upper trough will continue slide east away from
the east coast and southeast states Monday with dry NW flow over most
of the area except for far NE portions of the state where rare
upslope and isolated convection on the back side of a weak upper low
is expected in the afternoon. Tuesday should be dry as upper ridging
from the SW builds and a weak wave passes well to our north.

By Wednesday, large upper low centered over the northern Plains will
be pushing east into the Great Lakes with a wide swath of Westerlies
around it. The fringe of the Westerlies will move into north GA with
increasing moisture and some life, could see isolated convection
along and ahead of front in TN push south. Front and SWly flow aloft
pushes deeper into the state Thursday at which point spread in model
guidance increases significantly with one or two clusters indicating
a weak wave in the westerlies over the lower MS valley states early
Friday morning which is a very favorable pattern for widespread
showers and storms. Too soon to tell if conditions would be favorable
for severe storms or very heavy rain, but with what we see now, does
not appear to be too significant. This is supported by Day 7 and 8
SPC, WPC and CSU ML severe weather and heavy rainfall guidance.

Atlantic basin still indicates no tropical activity expected the
next 7 days.

SNELSON

&&

.AVIATION...
(00Z TAFS)
Issued at 756 PM EDT Sat May 18 2024

Line of thunderstorms is presently moving into the Atlanta metro
from the WNW. Expect frequent lightning, brief heavy rainfall, and
gusty winds (as high as 40 knots) as the line moves through. The line
is slowly weakening in intensity. Lowering cigs along with patchy
fog is expected again tonight, with IFR cigs likely and LIFR cigs
possible. Winds will shift to NE Sun morning in the Atlanta area and
AHN, with more northerly winds at CSG ad MCN. Models are trending a
bit drier with lingering showers and isolated storms on Sunday, with
better chances of showers in the morning at CSG and MCN near a post-
frontal trough.

//ATL Confidence...00Z Update...
Medium for late night cigs and vsbys along with coverage of
convection on Sunday. High for other elements.

SEC

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          63  79  60  83 /  60  40  10   0
Atlanta         65  80  63  83 /  50  30  10   0
Blairsville     58  75  58  78 /  60  50  10  20
Cartersville    62  81  61  84 /  60  30   0   0
Columbus        66  84  66  85 /  50  20  10   0
Gainesville     63  78  61  82 /  60  50  10  10
Macon           65  81  63  83 /  50  40  10   0
Rome            63  83  62  85 /  60  20   0   0
Peachtree City  64  81  62  83 /  50  30  10   0
Vidalia         68  80  65  83 /  50  60  20  10

&&

.FFC WATCHES/WARNINGS/ADVISORIES...None.

$$

SHORT TERM...SEC
LONG TERM....SNELSON
AVIATION...SEC