468
FXUS62 KFFC 201035 AAA
AFDFFC

Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
635 AM EDT Sun Jul 20 2025

...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Monday)
Issued at 350 AM EDT Sun Jul 20 2025

Key Messages:

- Isolated to scattered thunderstorms expected in the afternoon
  and evening both days.

- Heat and humidity typical of summertime persist, with the
  possibility of a Heat Advisory tomorrow (Monday).

Discussion:

The Southeast -- including Georgia -- remains within the grasp of
a subtropical ridge. Amid this ridge is a soupy airmass,
characterized by PWAT values of 1.7" to 2.2". This moist
environment coupled with daytime heating and destabilization will
support isolated showers and thunderstorms this afternoon and
evening. The isolated nature of convection means that portions of
north and central Georgia may end up not seeing any rain. The
Weather Prediction Center (WPC) has a Slight Risk (level 2 out of
4) for heavy rainfall leading to localized flash flooding across
northeast Georgia, with much of the rest of north Georgia under a
Marginal Risk (level 1 out of 4). Near-surface soil moisture is
most saturated across the higher terrain of northeast Georgia and
orographic lift could focus convection -- both of which warranting
the Slight Risk. A few strong storms with torrential downpours
and gusty winds will be possible. Heat index values will range
from the upper 90s to just shy of 105 degrees across much of the
forecast area.

The subtropical ridge will not be going anywhere tomorrow, nor
will the tropical airmass beneath it. As such, another day of
diurnally-driven isolated to scattered showers and storms is in
store. The Storm Prediction Center (SPC) has outlined portions of
north and central Georgia in a Marginal Risk (level 1 out of 5)
for severe thunderstorms posing a risk for damaging wind gusts at
50-60 mph. Additionally, WPC has the entire forecast area outlined
in a Marginal Risk for heavy rainfall leading to localized flash
flooding. Low-lying/flood-prone areas and urban areas will be most
vulnerable to heavy rainfall from strong and/or persistent storms.

Temperatures are progged to peak in the mid-90s to around 100
degrees tomorrow afternoon across portions of central and eastern
Georgia, with dew points in the mid-70s. The result will be heat
index values reaching 105 to 108 degrees. Unless we become
confident that cloud cover and/or rainfall will prevent heat index
values from rising this much, a Heat Advisory will likely be needed.

Martin


&&

.LONG TERM...
(Monday night through Saturday)
Issued at 350 AM EDT Sun Jul 20 2025

Key Messages:

- Very hot and humid conditions expected areawide Tuesday. Heat
  Advisory issuance is possible for portions of the area.

- Chances for showers and thunderstorms each afternoon through the
  extended, with greatest coverage Tuesday to Wednesday.

Discussion:

Much of the sensible weather in the extended range will be
governed by a mid-level subtropical ridge parked atop the
Southeast. A pocket of deep moisture rotating around the eastern
edge of the aforementioned ridge will support the development of
diurnal showers and storms -- likely to exceed "typical"
summertime afternoon coverage as it settles into the forecast area
proper by midweek. Coincident with the arrival of best moisture
throughout the column, a lobe of surface high pressure slides into
place across New England Tuesday into Wednesday. As it does so, a
backdoor cold front is pushed southwestward along the expanding
U-shaped isobars that characterize the wedge. Thunderstorms are
likely to quasi-organize along the advancing front, potentially
resulting in an east-to-west storm motion that is anomalous for
our area.

Global model guidance suggests comparatively drier air will be
ushered in aloft in the wake of our midweek convective peak -- not
enough to completely scour out chances for thunderstorms, but
enough to bring them back down to the low-end chance range
(20-40%) for much of the area from Wednesday on. As the frontal
energy settles along the northern Gulf, some semblance of a
baroclinic zone is likely to linger for the remainder of the week,
resulting in higher PoPs (40-60%) along our far southern tier/in
closest proximity to best remnant forcing.

Highs Tuesday will be in the mid-to-upper 90s for all bur far
northeast Georgia, which will remain in the 80s. Combined with
dewpoints progged to surge into the mid-70s and perhaps higher,
heat index values are likely to eclipse 105 degrees for large
swaths of the area. Heat Advisory issuance will likely be
necessary Tuesday. For Wednesday through Friday, drier air post-
front will allow dewpoints to drop into the mid-60s to lower-70s,
supporting a brief reprieve from truly oppressive humidity. With
highs expected to remain in the lower 90s, this forecaster
wouldn`t call it a pleasant latter half of the week, but it will
certainly be slightly more seasonable. Moisture looks to rebound
moving into next weekend, and heat index values will likely creep
back into the triple digits.

96


&&

.AVIATION...
(12Z TAFS)
Issued at 625 AM EDT Sun Jul 20 2025

A low-VFR cloud deck (~3.5 kft to ~4.5 kft) has developed over
metro Atlanta. This deck is struggling to drop lower, but given
the development of MVFR CIGs right before sunrise the last two
mornings, have opted for a TEMPO until 14z for MVFR CIGs. After
the morning clouds scatter, a Cu field will develop and stick
around through the afternoon. Maintaining a PROB30 at ATL and the
other metro sites for -TSRA after 18z. Still have just VCSH at MCN
and CSG. Winds will be west at 5-10 kts with gusts to ~20 kts.

//ATL Confidence...12Z Update...
Medium confidence on coverage of afternoon storms.
High confidence on all other elements.

Martin

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          94  75  97  75 /  10  10  30  10
Atlanta         92  77  94  77 /  30  10  30  10
Blairsville     87  68  89  68 /  30  20  50  20
Cartersville    92  73  95  73 /  30  20  40  10
Columbus        95  77  96  77 /  20  10  30  10
Gainesville     92  75  95  74 /  10  10  30  10
Macon           96  77  96  76 /  20  10  30  10
Rome            92  73  94  73 /  30  20  40  10
Peachtree City  93  73  94  74 /  30  10  30  10
Vidalia         97  78  98  78 /  20  20  40  20

&&

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

$$

SHORT TERM...Martin
LONG TERM....96
AVIATION...Martin