359
FXUS62 KFFC 181030
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
630 AM EDT Wed Sep 18 2024



...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Thursday)
Issued at 443 AM EDT Wed Sep 18 2024

This morning, the post tropical low has drifted over eastern
Tennessee. Calm winds within the relatively moist airmass may
produce areas of patchy dense fog that will last until daybreak.
Later today, a surface low is expected to spin up across central
Georgia along a boundary. Diurnally driven showers and possibly a
thunderstorm are expected this afternoon across far northeastern
Georgia and far central eastern Georgia. The best chance for
precipitation will be in northeast Georgia, while the best
instability, and thus thunderstorm chances, will be focused further
south across eastern central Georgia. However, there remains some
uncertainty over how far west storms could fire this afternoon in
this area. Temperatures will be a bit cooler across north Georgia
where more cloud coverage is expected to linger today. Temperatures
in this area will max out in the low 80s while areas further south
will climb into the upper 80s.

To our west, ridging aloft will begin to build in this evening and
into early Thursday. As the ridge helps usher the low pressure off
the eastern seaboard, skies will begin to clear overnight. Overnight
lows will drop into the 50s in the northeast Georgia mountains with
60s elsewhere. Tomorrow is expected to be dry with a low end chance
of rain in our furthest northeast counties. Under mostly sunny
skies, high temperatures will climb into the upper 80s for most
locations outside of the north Georgia mountains where temperatures
will remain generally in the 70s to low 80s.

KAB

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 443 AM EDT Wed Sep 18 2024

Key Messages:

  - Long term remains dry. Very little opportunity for rain until
    the end of the forecast period, and chances still remain low.

  - Increasingly looks like the end of the week into the weekend
    could be quite warm, with temps reaching into the upper 80s
    and even 90s.

Forecast Discussion:

The largest driver of change over the past 24 hours of the long
term seems to be the difficulty the models seem to be having with
the low pressure system over the area. This isn`t surprising - for
all intents and purposes, this is behaving like a cut off low, and
models will always struggle with these features in the absence of
strong upper level flow to push them along. Both the EPS and the
GEFS (alongside their deterministic counterparts) have seen a
shift towards bringing this low and surface low off the coast and
then developing a bit as it pushes towards the northeast. Without
anything to change our airmass, it is allowed to sit for several
days and continue to modify and heat, bringing day time highs
into the 80s and 90s by the weekend.

With this low off the coast, a bit more uncertainty has been
introduced over the weekend. The surface high expected to develop
to the north takes a bit more time to push into the area if the
surface low off the northeast is in place, which in turn prevents
us from being "wedged" as fast. The EPS is more in favor of this
scenario, keeping us warmer. The deterministic GFS and some of the
GEFS members also show this, but some of the GEFS hangs on to the
idea of the wedge coming in a bit faster, which would certainly
cool us a bit more than what is in the forecast for Sunday and
Monday. This forecast package will lean towards the wedge being
delayed a bit, as the guidance of late has struggled with the
amplitude of these lows off the coast being a bit underdone, so
forecast temps into Sunday remain in the upper 80s and 90s.

Temps cool down after this as it does still look like a CAD
airmass will move in. Rain chances with this still appear low.
After this, attention may turn to the tropics depending on how
development of a feature there begins in the next few days. Want
to note that despite what one model is showing, there is still
considerable spread among the wider ensemble, showing anything
from almost no development to systems that are just about anywhere
in the Gulf. Uncertainty remains very high overall.

Lusk

&&

.AVIATION...
(12Z TAFS)
Issued at 626 AM EDT Wed Sep 18 2024

VFR conditions currently but periods of IFR will be possible at
northern sites beginning between from 12Z to around 15Z. MVFR
vsby`s from 3-5SM are also possible at KRYY around sunrise.
Tonight, KMCN/KCSG will see MVFR vsbys from 06-10Z. Winds are
calm to VRB for much of the TAF period, but will be around 5KT or
less out of the NW during the day. Winds will shift to the NNE
after 02Z and will shift back to the NNW after 17Z at KATL.

//ATL Confidence...12Z Update...
Medium confidence on IFR cigs this morning and MVFR vsbys
overnight. High confidence on remaining elements.

KAB

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          63  85  64  87 /  10  10   0   0
Atlanta         65  87  66  88 /   0   0   0   0
Blairsville     59  80  58  83 /  10  10   0   0
Cartersville    63  87  62  90 /   0   0   0   0
Columbus        67  88  68  90 /   0   0   0   0
Gainesville     64  84  64  86 /  10  10   0   0
Macon           66  87  66  88 /  10   0   0   0
Rome            63  88  62  91 /   0   0   0   0
Peachtree City  63  86  64  88 /   0   0   0   0
Vidalia         68  87  67  86 /  10  10   0   0

&&

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

$$

SHORT TERM...KAB
LONG TERM....Lusk
AVIATION...KAB