186
FXUS62 KFFC 250918
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
418 AM EST Mon Nov 25 2024


...Morning Area Forecast Discussion...

.SHORT TERM...
(Today through Tuesday)
Issued at 346 AM EST Mon Nov 25 2024

Key Messages:

  - Warmer today with highs in the 70s across north and central GA.

  - Rain will push through tonight into tomorrow morning. Overall
    amounts should be a quarter of an inch or less in most locations.

Forecast:

Moisture advection from the Gulf is picking up this morning ahead of
surface low moving into the midwest with attendant cold front
draped over the southern Great Plains. The primary impact this
morning will be cloud cover that will put a stop to the
radiational cooling where it builds in, keeping low temperatures a
bit more elevated when compared to the previous night. Cloud
cover will likely remain into the afternoon hours across northern
Georgia, though the sun may peek out for a few hours before
sundown. WAA as a result of the surface mass response will bring
temps into the 70s across most of the area this afternoon, with
the potential exception of far northern Georgia where cloud cover
is expected to be the most persist.

Models bring the cold front through the area tonight into the early
morning hours of Tuesday as the surface low deepens over the Great
Lakes and continues to pull northeast. Most hi-res guidance shows a
line of showers and rain pushing in ahead of the surface front that
begins to degrade as it moves through the state as the front loses
the upper level support that is pulling away to the northeast. One
thing that has been "manually" added to the forecast is a small
chance of rain in parts of central Georgia well ahead of the front,
where model cross sections show the opportunity for some very
shallow isentropic lift that models can struggle to accurately
produce light drizzle or showers from. Overall amounts look to be
around a quarter of an inch in northern Georgia with a few isolated
higher amounts. 90th percentile amounts from models show half an
inch at best. This isn`t surprising given the rain looks to fall in
a short time period and should be lacking convective elements.

The highs on Tuesday will be made a bit challenging by the frontal
passage. If the front passes a bit more quickly than forecast,
current highs in the 70s in portions of central Georgia are likely a
bit overdone. Behind the front, cooler air should be filtering in
keeping highs in the 50s and lower 60s despite expected sunshine.

Lusk

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 346 AM EST Mon Nov 25 2024

At a glance:

    - Increasing chances for showers and thunderstorms on
      Thanksgiving

    - Unseasonably warm through mid-week, much cooler weekend

As we enter the extended range on Wednesday, north and central
Georgia are post (weak) front, with quasi-zonal flow aloft helping
to keep things warm -- unseasonably so, by 5-7 degrees -- and dry.
Moving into Thanksgiving Day, uncertainty remains amongst global
models about whether or not a pair of mid-level shortwaves digging
across the Four Corners and Northern Plains regions will: 1) phase,
deepening into a stronger trough and more progressive resultant
surface low or 2) remain separate, with a weaker surface mass
response and slower clearing of deep layer moisture from the column.
A stronger, quicker-hitting system is liable to drop more rain over
a shorter period of time, especially across portions of northeast
Georgia where totals will be inflated due to orographic influences,
while a slower, weaker system will produce lower QPF. The NBM
forecast, which incorporates both the Euro and the GFS, for rainfall
Thursday through early Friday afternoon shows a stark gradient: with
0.75-1" (and locally higher totals to as much as 21.5") for areas
along and north of the I-20/I-85 connector, and 0.25-0.75" for
locations to the south. Given proximity to the parent surface low,
will need to keep an eye on evolution of the mid-levels for the
potential for a few strong to marginally severe storms Thursday
afternoon/evening given a stronger front and progged weak SBCAPE (on
the order of 300-700 J/kg). Details are highly likely to change as
this event enters the short term and the purview of HiRes models,
but also as the primary shortwave moves into the mid-levels over
WCONUS in the next day or two, such that radiosonde data sampling it
can be assimilated into model guidance.

Breezy conditions are likely post-front Friday, with tightly packed
isobars evident in forecast surface analyses. Much cooler and drier
air looks to move in aloft, held in place by an eastward translating
surface high pressure system -- the center of which will move atop
the Deep South by Saturday -- sufficient to dry things out for the
weekend. Highs Wednesday and Thursday will be in the 60s to mid-70s,
dropping sharply behind the front to just the 40s to mid-50s from
Friday onward (cannot rule out failing to breach the upper-30s for
portions of northeast Georgia). Lows will flip-flop between the 30s
to mid-40s and the 50s Wednesday through Friday, before dropping
into the 20s to lower 30s.

96

&&

.AVIATION...
(06Z TAFS)
Issued at 1256 AM EST Mon Nov 25 2024

VFR to start TAF period. MVFR cigs expected to build in across NW
GA that could encroach upon metro TAF sites and CSG by 11Z. TEMPO
in place mostly for uncertainty in coverage of cloud deck. Winds
will be SW through period. Cigs should become SCT by afternoon.
Cigs expected to build back in by 00Z, with lowering to MVFR
overnight as a band of SHRA approach TAF sites.

//ATL Confidence...06Z Update...

Medium cigs, high all others.

Lusk

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          70  56  69  43 /   0  20  10   0
Atlanta         70  55  63  43 /   0  30   0   0
Blairsville     64  46  59  37 /   0  60   0   0
Cartersville    72  50  61  37 /   0  50   0   0
Columbus        74  57  71  45 /   0  20  20   0
Gainesville     68  56  65  43 /   0  30   0   0
Macon           72  56  71  45 /   0  20  20   0
Rome            71  49  61  36 /   0  60   0   0
Peachtree City  71  54  65  38 /   0  30  10   0
Vidalia         74  56  74  53 /   0  10  10   0

&&

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

$$

SHORT TERM...Lusk
LONG TERM....96
AVIATION...Lusk