-- Discussion containing changed information from previous version are highlighted. --
162
FXUS62 KFFC 221724
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
124 PM EDT Sat Jun 22 2024



...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Sunday)
Issued at 345 AM EDT Sat Jun 22 2024

At a glance:

    - Unseasonable warmth continues

    - Isolated to scattered afternoon thunderstorms return

Sensible weather for the remainder of the weekend will continue to
be governed by a strong (~2.5 sigma above average, per ensemble
guidance) -- albeit retrograding -- mid-level ridge. At the surface,
weakening high pressure will give way to relatively ambiguous low-
level flow. Previously deemed Invest 92L has since moved inland over
southeast Georgia, bringing with it increased cloud cover and a slug
of tropical moisture to break up our otherwise dry airmass.
Associated impacts will be relatively benign, with 30-50% chances
for showers and thunderstorms for areas south and east of Macon, and
highs just a tick lower in the aforementioned areas this afternoon
(1-2 degrees; still in the lower-90s).

On Sunday, expect summertime, diurnally-driven convection, primarily
across the southern and eastern portions of the forecast area, given
forecast PWATs north of 1.7" (~90th percentile for late June per
SPC`s sounding climatology) and highs reaching well above convective
temperatures.

After several days of moderation under subsidence and clear to
mostly clear skies, highs through Sunday will be sufficiently warm.
Today, expect temperatures to surge into the lower-to-mid 90s for
all but the terrain of northeast Georgia, which will remain in the
80s. Tomorrow, highs will be a few degrees warmer, in the mid-to-
upper 90s areawide. Improved moisture will allow for trends toward
"air you can wear" for Sunday, and heat index values will likely
breach the triple digits (as high as 102F) east of a line extending
from Macon to Athens. Be cautious if spending long periods of time
outside on Sunday, and take frequent hydration breaks in the shade.

96

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 345 AM EDT Sat Jun 22 2024

As the extended period begins on Sunday evening, upper level
troughing will be setting up over the northeast CONUS. Meanwhile, a
surface low associated with this trough will extend a cold front
southwestward into the Tennessee Valley region by Sunday night. A
shortwave dropping through the Great Lakes region will serve to
amplify the trough, which will also give the front an additional
southward push towards north Georgia. As this occurs, scattered
showers and thunderstorms will spread into far north Georgia on
Sunday night, advancing southward through the overnight hours and
into Monday. The front is likely to stall in during the afternoon on
Monday without providing much change in the weather conditions. High
temperatures are forecast to rise into the low to mid 90s in north
Georgia and upper 90s in central Georgia. Diurnally-driven
thunderstorms on Monday afternoon will be highest in coverage to the
south of the front where the most atmospheric moisture will remain.
Relatively lower dewpoints (in the mid 60s) are anticipated behind
the front on Monday night into Tuesday. A 500 mb ridge will move
advance towards the eastern CONUS on Tuesday, with surface high
pressure setting up over the Appalachians. Drier air underneath this
pattern will be short-lived, as diurnally-driven convection will
return on Tuesday afternoon and occur once again on Wednesday.

It will be important to keep an eye on temperatures throughout much
of the week. NBM guidance continues to show temperatures in the mid
to upper 90s across the majority of the forecast area, and some
locations in east-central Georgia reaching above 100 in portions of
east Georgia Monday through Wednesday. For this forecast package, I
elected to blend in NBM10percent guidance into the high temperature
guidance. As convective temperatures are reached and storms
subsequently develop, the rain and increased cloud cover can often
prevent us from reaching such high temperatures. Regardless, even
with trending high temperatures down, they are still forecast to
range from between 6-12 degrees above average for late June and
still rise into the mid to upper 90s each afternoon. With more
moisture than the previous spell of heat, so heat indices are
forecast to creep up into the triple digits, and heat products may
be warranted. Overnight lows are also not anticipated to provide
much relief falling into the low to mid 70s.

By late Wednesday, the ridge will shift eastward off the Atlantic
coast as a longwave trough extends from the eastern Great Lakes
towards the Lower Mississippi River Valley. Model guidance continues
to indicate an associated frontal system approaching Georgia on
Thursday, but uncertainty remains with respect to timing and
strength. Maintained high-end chance to low-end likely PoPs late
Wednesday into Thursday to account for increased precip chances
ahead of a potential front, but also reflect lingering uncertainty.

King

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 114 PM EDT Sat Jun 22 2024

VFR conditions will prevail through the TAF period. SCT cu in 5-7
kft range will diminish after sunset before forming again by
15-16Z Sunday. E to SE winds at 4-7 kts will diminish to light and
vrb to near calm after 00Z. Wind direction will shift W after 12Z
Sunday with speeds 3-6 kts.

//ATL Confidence...18Z Update...
High confidence.

RW
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Athens          71  96  74  96 /  10  10  20  20
Atlanta         74  97  77  95 /   0  10  20  30
Blairsville     67  89  69  89 /  10  10  40  30
Cartersville    71  96  73  95 /   0   0  30  30
Columbus        74 100  76  97 /   0  10  10  30
Gainesville     72  94  75  93 /  10  10  20  20
Macon           73  99  76  97 /  10  10  10  30
Rome            72  98  74  95 /   0  10  40  30
Peachtree City  72  98  74  95 /   0  10  20  30
Vidalia         74  97  77  98 /  20  40  30  40
-- End Changed Discussion --

&&

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

$$

SHORT TERM...96
LONG TERM....King
AVIATION...RW