-- Discussion containing changed information from previous version are highlighted. --
571
FXUS62 KFFC 200150
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
950 PM EDT Thu Sep 19 2024



...Evening Update...

.UPDATE...
-- Changed Discussion --
Issued at 949 PM EDT Thu Sep 19 2024

No major updates to the forecast. Clear overnight tonight, with no
PoPs tomorrow.
-- End Changed Discussion --

&&

.SHORT TERM...
(This afternoon through Friday)
Issued at 254 PM EDT Thu Sep 19 2024

Currently satellite is showing scattered cumulus across the area as
the low pressure continues to spin over the NC/VA border. Chances
for showers have gone down a tad this afternoon/evening, but there
is still ~15% chance for the showers from wrap around moisture from
the low pressure system. CAPE values between 500-1000 J/kg are
currently over the northeast GA mountains with around 20kts of
shear. Should any showers be able to form, the ingredients would be
there to have thunderstorms. Temps will continue to warm into the
mid 80s today.

Tomorrow, the high pressure over the southwestern CONUS will start
to push eastward into the area as the low pressure moves well east
of the area. With this, rain chances will be near zero tomorrow
along with thunderstorm chances. Temps will rise into the upper 80s
to low 90s tomorrow as the high pressure sits over the area and
causes cloud cover to be less than today. A wedge begins to set in
as well during this time frame resulting in drier and sunny
conditions. Overall, summer 2.0 is making a comeback starting
tomorrow unfortunately.

Hernandez

&&

.LONG TERM...
(Saturday morning through next Wednesday)
Issued at 254 PM EDT Thu Sep 19 2024

The forecast is mainly on track for the extended period, with
unseasonably warm conditions (summer 2.0) expected through the
weekend and into next week. At this time, the hottest days are
forecast from Saturday through Monday, when afternoon highs are
expected to reach into the low 90s across the majority of the
forecast area each afternoon. Much uncertainty remains with the
respect to potential tropical development in the Caribbean/Gulf of
Mexico, not only indicating a wide variety of tracks, but also in
indicating whether or not a tropical system even forms. Will
continue to monitor as guidance comes into better agreement. The
previous discussion follows...

King

PREVIOUS DISCUSSION...

Key Messages:

  - Warm temperatures that will be 8-13 degrees above average in
    parts of north Georgia through the weekend.

  - Complex upper air pattern combined with tropical uncertainty
    make for a difficult mid to end of week forecast next week.

Forecast Discussion:

The main meteorological players at the beginning of the long term
will be a low pressure off the shore of New England that models
have settled in on forming, a mostly stagnant airmass over us, and
a developing surface high well to the north over the Canadian
maritime. Into Saturday, this low doesn`t look like it will have
pushed any cooler air into us, so our drier air will continue to
heat bringing temperatures into the 90s in some locations. This
low slowly slides to the south on Sunday as the surface high seeps
around it into the northeast. The models show signs of a surface
boundary push down the Appalachians, but for now do not bring it
in. This may be the first place where we can discuss a little
uncertainty, as models can struggle with the timing and strength
of these airmasses as they filter down the Appalachians, but given
the unusual location of the surface high, there are reasons to
believe CAD processes may not be as dominate yet.

More uncertainty introduces itself after this, with more players
entering the forecast. A cut off upper low currently over
California is expected to eject into the Plains developing an
attendant surface low. The exact timing, track, and even strength
of this low has decent uncertainty, and how close it gets to the
CWA will have implications for moisture draw from the Gulf and
potentially whether the wedge may run into additional challenges
moving into the area. The surface low off the coast is expected to
continue diving south, allowing the wedge to attempt to move into
the area, but the high pressure to the north of the low does
appear to begin to weaken a bit, decreasing the pressure gradient
and the potential strength of the CAD. So, this creates some
spread in the temperature forecast. NBM 10th and 90th percentiles are
about 5-7 degrees apart Monday and Tuesday across the CWA, higher
in the north and northeast.

Adding even more fuel to the fire by the end of the long term will
be the tropics. Generation of a broad low off central America
continues to look likely. While the probability that a tropical
system forms from this is increasing, there are still a wide
variety of possibilities ensembles continue to show in terms of
timing, strength, and position of any system, if one is even able
to form. Broad lows can help spark the formation of these systems
by providing a focus for convection and vorticity maxima, but
organization of these broader systems can sometimes be a struggle
for a variety of reasons. Once again, don`t pay attention to
single runs of models. Take clues from the broader ensemble, which
still highlights a wide range of possibilities.

Lusk

&&

.AVIATION...
(00Z TAFS)
Issued at 739 PM EDT Thu Sep 19 2024

VFR through period. Scattered to few deck 4-5kft through sundown,
clearing overnight. Winds variable and light overnight. Tomorrow
expecting similar conditions, sct cigs around 3-5kft. Winds
generally NE to E, though could be variable at times given light
conditions.

//ATL Confidence...00Z Update...
High all elements.
SM

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          64  88  65  90 /   0   0   0   0
Atlanta         67  89  68  90 /   0   0   0   0
Blairsville     59  84  60  85 /   0   0   0   0
Cartersville    64  90  65  92 /   0   0   0   0
Columbus        69  90  68  91 /   0   0   0   0
Gainesville     65  88  66  89 /  10   0   0   0
Macon           66  89  66  90 /   0   0   0   0
Rome            64  91  64  92 /   0   0   0   0
Peachtree City  65  88  65  90 /   0   0   0   0
Vidalia         69  88  67  88 /   0   0   0   0

&&

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

$$

SHORT TERM...Hernandez
LONG TERM....Lusk
AVIATION...SM