740
FXUS62 KFFC 201047
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
647 AM EDT Tue May 20 2025

...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Wednesday)
Issued at 354 AM EDT Tue May 20 2025

Key Messages:

 - A line of strong to severe thunderstorms will move through
   Georgia between 7 PM Tuesday and 9 AM Wednesday. Severe
   thunderstorms will be capable of producing damaging winds,
   hail, and a few brief tornadoes.

 - The greatest risk for severe weather is expected across far
   north and northwest Georgia.

 - Drier conditions are expected on Wednesday after precipitation
   exits the area.

A 500 mb ridge is currently extending from the north Florida
Peninsula towards the northern Great Lakes. This ridge is caught
between two longwave troughs, one extending over the western
Atlantic and the other to the immediate east of the Rockies. The
axis of the ridge will cross Georgia early this morning and continue
to move eastward through the afternoon. Aside from low 60s in the
higher elevations of far northeast Georgia. Low temperatures this
morning will start out in the upper 60s to near 70s across the area.
With light winds and a moist, nearly saturated airmass at the low
levels, patchy fog and scattered low level clouds will be possible
once again in the early morning hours today, which will dissipate by
mid-morning. Under the influence of the ridge and to the south of a
warm front, temperatures will be warm across the forecast area once
again this afternoon, with highs rising into the mid 80s to low 90s
in north Georgia and low to mid 90s in central Georgia.

As the western longwave trough elongates to the southeast (becoming
negatively tilted in the process) this afternoon, a lobe of
shortwave energy and an associated speed max will swing through the
Mississippi River Valley. A surface low over the Midwest will extend
a cold front southward across Kentucky/Tennessee/Alabama. Shower and
thunderstorm activity is expected to arrive in the far northwest
Georgia by this evening as the cold front continues to advance
towards the forecast area. Within the warm and moist environment,
SBCAPE values are progged to range from 1500-2000 J/kg. Furthermore,
0-1 km shear values and deep layer bulk shear values are forecast to
be strong ahead of the frontal boundary, between 30-40 kts and 45-55
kts respectively. With shear vectors oriented roughly parallel to
the orientation of the front, the storms ahead of the front are
anticipated to take on a linear convective mode. Storms embedded
within the line will have the potential to become severe. The
primary hazard associated with any severe thunderstorms will be
damaging straight line winds associated with bowing segments. Severe
thunderstorms could also be capable of producing severe hail to the
size of 1 inch or slightly greater, as a secondary threat. A look at
hi-res model soundings also reveals low-level curvature in the
hodographs, which aligns 0-1 km storm relative helicity values up
to 150-250 m2/s2 in northwest Georgia. This could contribute to
the development of a few brief tornadoes if conditions align
properly.

The greatest potential for severe weather will be along and north of
a rough line from Rome to Blairsville Georgia between 7 PM and 1 AM
where a combination of strong forcing, upper level support, and
instability are most likely to come together. Here, the SPC has
introduced an Enhanced Risk (level 3 of 5) for severe weather.
Showers and thunderstorms are expected to continue to advancing
southeastward through the overnight hours. The severe threat will
gradually diminish overnight into early Wednesday morning as surface-
based instability decreases, the front loses the upper level support
from the shortwave aloft, of the low level forcing ahead of the
front weakens. The threat will also become more conditional as
storms move southward and it becomes progressively less likely that
the necessary ingredients will align favorably. Several storms after
1 AM will still be capable of producing damaging wind gusts, and a
brief tornado also cannot be ruled out. A Slight Risk (level 2 of 5)
for severe weather is in place to the south of the aforementioned
Enhanced Risk and along and north of a line from LaGrange to Athens,
with a Marginal Risk further south, still.

Rainfall totals associated with this system will range from 0.5 to 1
inch to the north of I-20, with lesser amounts to the south. Though
stronger storms could produce locally heavy rainfall, the fast
forward movement of the line should preclude flash flooding
concerns. Precipitation is expected to exit the forecast area to the
southeast by mid-morning on Wednesday. After this point, drier mid
level air and northwesterly low level winds will progressively build
into the area behind the cold front. This will inhibit the chances
for additional precipitation on the back side of the front and
promote clear skies through the afternoon. High temperatures on
Wednesday will be in the upper 70s to low 80s to the north of I-85,
though they will still rise into the mid 80s to low 90s to the south
where it will take longer for cooler air to filter in.

King

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 354 AM EDT Tue May 20 2025

Key Messages:

  - Generally calm with temperatures slowly climbing.

  - High uncertainty in timing the next major pattern change.

Line of Thunderstorms Exits the CWA:

The line of thunderstorms will continue to make its way southeast
out of the CWA. As the sunrises, remaining thunderstorms may be
possible though upper level support will be disconnecting from the
line itself. Main threat would be locally gusty winds and heavy
rainfall.

Wednesday onward: Conditions will be mostly dry and cool through the
end of the long term outlook. Highs in the 70s and 80s will slowly
climb as the subtropical ridge builds in (not as strong as before).
A few thunderstorms may be possible Saturday and Sunday across far
north Georgia as a series of shortwaves moves to the north.
Confidence in thunderstorm activity through the weekend is low due
to uncertainty in the strength of the upper level trough. Should it
slow down, expect increased thunderstorm coverage across north
Georgia. Not anticipating severe at this time.

Longer range models have begun to suggest a potential pattern change
going into next week, however wouldn`t put too many chips into this
basket just yet.

SM

&&

.AVIATION...
(12Z TAFS)
Issued at 639 AM EDT Tue May 20 2025

IFR ceilings and fog present in west-central Georgia, including
CSG, as the morning begins. Scattered MVFR level clouds could
furthermore make it as far north as ATL between 12-14Z. Conditions
are expected to become VFR across the forecast area by 15Z, with a
cu field between 035-050 this afternoon. Winds will be SW through
the day, between 4-8 kts this morning and increasing to 8-12 kts
with gusts of 18-22 kts this afternoon. A line of TSRA will enter
far north Georgia this evening, passing through the metro area
between 03-07Z. There is a PROB30 for TSRA between 04-07Z at ATL,
05-08Z at AHN, and a couple of hours later for MCN/CSG. MVFR
conditions will be possible behind the storms after 08Z at ATL.

//ATL Confidence...12Z Update...
Medium confidence on the timing and coverage of SHRA/TSRA tonight.
High confidence on all other elements.

King

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          89  68  85  60 /  10  50   0   0
Atlanta         90  69  84  63 /  10  70   0   0
Blairsville     84  62  77  54 /  20  90   0  10
Cartersville    90  67  83  59 /  10  80   0   0
Columbus        91  69  88  62 /   0  70  10   0
Gainesville     89  68  82  60 /  10  80   0   0
Macon           91  70  90  62 /   0  60  10   0
Rome            89  67  83  58 /  20  80   0   0
Peachtree City  90  67  85  60 /   0  60   0   0
Vidalia         93  73  91  64 /   0  30  30   0

&&

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

$$

SHORT TERM...King
LONG TERM....SM
AVIATION...King