173
FXUS62 KFFC 120640
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
240 AM EDT Mon May 12 2025


...Morning Area Forecast Discussion...

.SHORT TERM...
(Today through Tuesday)
Issued at 230 AM EDT Mon May 12 2025

Key Messages:

 - Isolated severe thunderstorms are possible today, with damaging
   winds being the primary threat. An brief tornado or marginally
   severe hail can`t be ruled out.

 - Rainfall will continue in the region today and Tuesday, but
   the overall threat for flooding appears to be declining.

Whats Going on Today & Tuesday:

A trough digging into the Intermountain West will provide the kick
needed to get the closed low over Louisiana moving again. As the low
is absorbed back into the prevailing flow it will lift northeast
towards the Tennessee Valley. This path will keep Georgia under
prevailing southerly to southwesterly flow in the mid and upper
levels and continue to advect Gulf moisture over the state.
Occasional shortwaves will ride through the prevailing flow
enhancing lift and leading to periods of increased rain shower and
thunderstorm activity. A couple off these storms could be severe or
lead to localized flooding (see below for additional details).

Temperatures should rebound today and Tuesday compared what the
region experienced over the weekend. Our forecast generally follows
the 50th percentile of the NBM guidance. The one deviation from this
can be found in northeast Georgia where we adjusted forecast high
temperatures down towards the 25th percentile to account for
potential of widespread rainfall this afternoon. Thus our forecast
favors high temperatures in the low to mid 70s in northern Georgia
today and Tuesday. In central Georgia highs should encroach upon 80
degrees both days.

The Severe Weather Threat:

A shortwave rotating around the parent low in Louisiana will push a
line of showers and thunderstorms out of Alabama and into Georgia
this morning. The airmass being ingested by these storms should be
modestly unstable (MUCAPE 700-1400 J/kg) as they move into Georgia.
The storms will also be working with a respectable amount of low
level helicity (0-1 km 75-200 m2/s2) within an environment with STP
values in the 1-4 range. These two factors may contribute to the
formation of isolated low topped supercells and a non-zero risk for
brief tornadic spin-ups this morning in western Georgia. Any
tornadoes would likely be brief in nature and towards the lower end
of the EF-Scale (EF0-EF1). A couple of the storms could also produce
damaging wind gusts in the 40 to 60 mph range. Overall the severe
risk remains Marginal (level 1 out of 5). As the line moves into
eastern Georgia this afternoon the very low risk for a brief tornado
will continue. We`ll monitor east central Georgia closely as the
CAMs give this area the best combination of low level helicity and
instability. Additional thunderstorms may develop once the initial
line moves through due to diurnal heating (especially in western
Georgia). The primary threat with any of these storms should be
downburst winds, but an isolated storm with marginally severe hail
can`t be ruled out.

Shower and thunderstorm activity should reach a minimum tonight
before diurnal heating and our proximity of the upper level low
trigger more widespread activity Tuesday afternoon. The parameters
for severe weather don`t look overly impressive on Tuesday. However
we will need to keep and eye on central Georgia where MUCAPE values
in the 1000-1500 J/kg range, 0-6 km shear of 20 to 30 kt, and PW
values between 1.4 and 1.7 inches could produce a couple of stronger
storms with a damaging wind potential.

Additional Rainfall & Flooding Concerns:

The overall flooding threat in the region seems to be on the
decline, though there are couple areas that could see issues if
conditions line up just right. The first is in east central Georgia
where a deep fetch of subtropical moisture continues to stream in
from the south. Thunderstorm activity within this band and hourly
rain rates have generally be on the decline in the last 4 hours.
This suggest that any lingering flash flooding threat with this
feature may be limited to areas like Toombs County where significant
rainfall fell over the last 12-18 hours. Our focus will also be on
western Georgia this morning as a line of storms slowly moves in
from Alabama. Greater instability should lead to more thunderstorm
activity, but lower PW values (generally 1.5 in or less) may limit
hourly rain rates to 1-2 inches per hour. Combine this with 3 hour
flash flood guidance in the 2-3 inch range and we would need storms
to train over the same area for several hours to generate a
significant flash flood threat. This area also includes the current
Flood Watch, which we have kept active for now despite the declining
flood threat. The morning shift may consider ending the Flood Watch
once the initial line of storms moves through. The final area of
concern for potential flooding looks to be the mountains of
northeast Georgia, where training of thunderstorms and upslope flow
may combine to generate higher rain rates this afternoon.

A low risk for minor river flooding continues across all of north
and central Georgia. A couple of gauges are progged to reach action
stage and the Ocmulgee River near Macon has the potential to tip
over into minor flood stage. Additional rainfall totals of 0.75 to
2.5 inches between this morning and Tuesday may contribute to
additional river rises.

Albright

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 230 AM EDT Mon May 12 2025

Key Messages:

 - A warming trend will accelerate Wednesday, with widespread
   highs in the upper 80s and lower 90 expected next weekend.

 - Thunderstorm activity may return to the region next weekend.

An upper level trough lingering over the Eastern U.S. will allow
scattered showers and thunderstorms to linger in Georgia through
Wednesday. Overall storm coverage on Wednesday should peak during
the afternoon with the max in diurnal heating. Projected lapse
rates in the 6.5-7.5 C/km range, MUCAPE > 1000 J/kg, and 0-500 mb
bulk shear of 25-35 kt suggests a non-zero chance for strong or
severe storms Wednesday afternoon and evening. If these
conditions hold it wouldn`t be surprising if the SPC eventually
places us under a Marginal (level 1 out of 5) Risk for severe
weather.

A transient upper level ridge will move over Georgia Thursday.
This should result in dry weather and warming temperatures.
Widespread afternoon highs in the upper 80s are expected (5 to 10
degrees warmer than average).

As we move into the upcoming weekend, guidance for the global
ensembles (GEFS & EPS) favors warm and humid conditions. Surface
dewpoints should be in the upper 60s or lower 70s, and with highs
in the upper 80s or low 90s it will feel like summer. Near zonal
flow over the Southeast may also bring several shortwave troughs
through the region between Friday and Sunday. Timing of these
troughs varies in the model guidance, but there presence along
with significant instability (due to the heat and humidity)
indicate the potential return of thunderstorm activity. At this
time guidance from the EPS favors Saturday and Saturday night for
the most widespread storm coverage. The GEFS suggest greater
uncertainty, spreading the threat out over the weekend and early
next week.

Albright

&&

.AVIATION...
(06Z TAFS)
Issued at 152 AM EDT Mon May 12 2025

A mix of MVFR, IFR and LIFR conditions (ceilings 300-1500 ft AGL &
visibility 2 to P6SM) will continue in the region through 18Z
today. Then conditions should improve to a mix of VFR and MVFR
between 18Z today and 06Z Tuesday (ceilings 1500-5000 ft AGL).
Rain showers and scattered thunderstorms will continue in the
region through at least 06Z Tuesday, with the greatest coverage
expected between 10Z today and 00Z Tuesday. All TAF sites should
be impacted by storms at some point. Surface winds will gradually
transition from an eastelry direction to a southeasterly
direction as today progresses.

//ATL Confidence...06Z Update...
Moderate confidence in the timing of thunderstorms this morning,
and low confidence in the thunderstorm potential this afternoon.
High confidence in a transition to MVFR or VFR ceilings this
afternoon.
High confidence in the continuation of easterly winds today.

Albright

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          76  60  75  59 /  80  60  80  50
Atlanta         78  61  75  61 /  80  40  80  40
Blairsville     71  56  69  54 /  90  60  90  50
Cartersville    79  58  75  59 /  70  50  80  40
Columbus        81  60  79  61 /  70  20  40  20
Gainesville     75  61  73  59 /  90  70  80  50
Macon           81  61  79  61 /  70  30  60  30
Rome            80  59  77  59 /  70  50  80  40
Peachtree City  79  58  77  59 /  70  40  70  30
Vidalia         81  64  81  64 /  70  40  40  40

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 2 PM EDT this afternoon for GAZ078>080-089>093-
102>106-108.

&&

$$

SHORT TERM...Albright
LONG TERM....Albright
AVIATION...Albright