876
FXUS62 KFFC 241810
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
210 PM EDT Tue Sep 24 2024

...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Wednesday)
Issued at 407 AM EDT Tue Sep 24 2024

One more day of temperatures well above normal. Values continue 5
to 15 degrees above normal for this time of year. ATL could be
close to setting a record high temp again today. Have blended in
some warmer guidance again today. However, there could be a bit
more cloud cover around today keeping temps in the lower 90s
instead of the middle/upper 90s.

500mb ridging is situated west to east across the northern GOMEX.
A longwave trough is across the central part of the country. The
trough will make some slow progress eastward today and begin to
approach the Mississippi River later Wednesday. At the surface,
high pressure remains along the Gulf Coast. A weak frontal
boundary is close to crossing the Mississippi River. The front
will also make slow eastward progress through the short term,
crossing the Mississippi River by midday Wednesday.

Pops will continue to be a bit disorganized today. A weak trough
remains across central GA. If there is a focus for precip today,
think the trough should be it, but pops remain isold to chance. As
the front approaches, tropical moisture will begin to pool along
it. The highest pops will be along and just east of the front
overnight and Wednesday. With PWATS 2"+ along the front, locally
heavy rainfall will be possible overnight and Wednesday,
especially across the NW portions of the state.

NListemaa

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 407 AM EDT Tue Sep 24 2024

Potential Tropical Cyclone Nine is forecast to become a major
hurricane as it approaches the northeastern Gulf Coast (AL, GA,
and FL coasts). Landfall is expected to occur sometime between
Thursday morning and Friday morning (with the current cone graphic
showing landfall around 8 PM Thursday). The system is expected to
track to the north/north-northeast at a fast pace as it is
steered by a mid/upper-level trough to the west and a mid/upper-
level ridge to the east. Now 3-4 days out from the event, and
after several days of agreement among the ensemble guidance,
confidence in impacts across north and central Georgia is
increasing. Details below...

Rainfall: Widespread showers and embedded thunderstorms are
expected from Wednesday night through Thursday night, with precip
expected to taper off from south to north on Friday. Widespread
rainfall totals of 4-6 inches are expected with localized totals
of 7+ inches. These localized rainfall maxima are expected within
especially intense rainbands (the location of which are difficult
pinpoint more than 24 hours out) and/or in the mountainous terrain
of north Georgia, where orographic uplift will enhance warm rain
processes. Much of the forecast area along and east of a line from
Columbus to Marietta to Gainesville (including Atlanta) is
outlined in a Moderate Risk (level 3 of 4) for excessive rainfall
from Thursday morning to Friday morning, indicating the potential
for flash flooding and river flooding. It is currently outside the
time frame for issuance of a Flood Watch.

Winds: Given the intensity and forward speed of the system,
strong winds will likely persist farther inland than they would
with slower moving systems. Conditions will become increasingly
breezy over the course of Thursday, with the wind field associated
with the system arriving across the southern portion of the
forecast area on Thursday evening. As the system tracks farther
inland on Thursday night and Friday morning, winds will become
strong essentially area-wide with the forecast currently calling
for 25-35 mph winds sustained (with localized stronger winds near
the center of circulation) and gusts of 35-55 mph (again, with
localized stronger gusts near the center of circulation). These
strong winds -- along with periods of heavy rainfall and resulting
moisture-laden soils -- could lead to areas of tree damage and
power line damage. It is currently outside the time frame for
issuance of a Tropical Storm Watch.

Tornadoes: Storm Prediction Center (SPC) has introduced a
Marginal Risk (level 1 of 5) across east-central Georgia for
tropical cyclone tornadoes from Thursday morning to Friday
morning. This Marginal Risk area may be refined over the next day
or so, but whatever portion of the forecast area ends up on the
immediate eastern side of the system will have potential for low-
topped supercells and thus short-lived tornadoes, due to the
tropical airmass and ample low-level shear.

The system will be absorbed into the mid-latitude flow by Friday
and enhance a broad area of low pressure and troughing over the
Southeast through Monday. This setup -- along with residual
tropical moisture -- suggests that isolated showers will be
possible each day. The ample rainfall and cloud cover through the
period will keep high temperatures in the mid-70s to mid-80s, with
cooler temperatures in the mountains.

Martin

&&

.AVIATION...
(18Z TAFS)
Issued at 152 PM EDT Tue Sep 24 2024

Latest radar shows widely sct shra this aftn. Iso tsra cannot be
ruled out with marginal instability in place. SCT to BKN cu field
expected through 02z with high clouds increasing. Lower MVFR to
FEw/SCT BKN deck starts to move in ahead of a frontal boundary in
northwest GA after 06z settling in through the metro closer to
12z. Additionally, VCSH starts as early as 14z with onset of -SHRA
between 16-18z. Did introduce a PROB30 for tsra at ATL tomorrow
afternoon. Winds start off from the southwest, become light/vrb
overnight <5kts, and then switch over to the SE side 08z-10z and
stay on this side through 18z.

//ATL Confidence...18Z Update...

Medium confidence on all elements.

07

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          68  83  68  75 /  30  60  70  90
Atlanta         70  82  68  74 /  40  80  80  90
Blairsville     63  75  62  70 /  60  80  80  90
Cartersville    68  80  66  75 /  60  90  80  90
Columbus        72  85  69  76 /  30  80  80  90
Gainesville     68  78  67  73 /  40  80  80  90
Macon           70  88  70  77 /  20  50  70 100
Rome            68  80  66  76 /  70  90  80  90
Peachtree City  68  82  67  74 /  40  80  80  90
Vidalia         70  88  72  80 /  10  20  60  90

&&

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

$$

SHORT TERM...NListemaa
LONG TERM....Martin
AVIATION...07