669
FXUS62 KFFC 190007
AFDFFC

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

...New 00Z Aviation Discussion...

.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...Martin
LONG TERM....SNELSON
AVIATION...SEC