-- Discussion containing changed information from previous version are highlighted. --
756
FXUS62 KFFC 261723
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
123 PM EDT Wed Jun 26 2024



...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Thursday)
Issued at 423 AM EDT Wed Jun 26 2024

At a glance:

    - Unseasonable heat continues

    - Chances for showers and thunderstorms return tonight through
    tomorrow

Throughout the day today, the mid-levels will begin to transition
away from northwesterly flow as a shortwave rounding the base of a
broader mid-level trough -- currently lifting across the Great Lakes
-- approaches from the northwest. With a weak lobe of high pressure
lingering at the surface, our uncharacteristically dry airmass will
remain in place for another day. Dewpoints this afternoon will once
again drop into the mid-50s to lower-60s, between the 10th and 25th
percentile per SPC`s Sounding Climatology, under the influence of
impressive mixing. Highs this afternoon are expected to surge back
into the upper-90s to lower triple digits this afternoon, supportive
of dewpoint depressions of 35-40 degrees (!). This, combined with
stout capping lingering at the top of our mixed layer (shown well on
yesterday`s 26/00Z sounding), should be enough to continue to
prevent meaningful rain chances this afternoon -- aside from an
isolated shower or thunderstorm in the vicinity of the stalled front
along our far southern tier. After multiple days without meaningful
rainfall, fine fuels are bone dry (<5% moisture), so have opted to
issue a Fire Danger Statement for areas along and east of a line
extending from the Atlanta Metro to Macon. Use extreme caution if
planning any outdoor burns.

Late this evening, the aforementioned shortwave will breach the
state line from the northwest, bringing with it a slug of moisture.
Chances for showers and thunderstorms will initially be relegated to
areas north and west of the Metro through daybreak Thursday, but
will spread to the south and east through the day, increasing into
the afternoon to blanket 30-40% chances. Forecast rainfall totals
are far from impressive at this time, between a tenth and a half of
an inch, but locally higher amounts are possible in areas that
experience more convective rainfall. With more cloud cover in the
forecast, highs will be the "coolest" we`ve felt in several days, in
the upper-80s to lower-90s north of I-85 and the mid-90s elsewhere.
This slight drop in temperatures will counteract the stark increase
in moisture (dewpoints in the upper-60s to 70s Thursday afternoon
vs. the 50s to lower 60s on Wednesday afternoon) such that heat
index values remain in check.

96

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 423 AM EDT Wed Jun 26 2024

On Thursday night, the axis of the upper level trough will have
cleared Georgia to the east and will be moving towards the Atlantic
coast. Isolated showers and thunderstorms will persist in portions
of east and central Georgia, but are expected to diminish in the
hours after sunset. Broad upper level ridging is expected to set up
over the eastern CONUS in the wake of the trough on Friday, and
persist into the weekend. A more typical summertime pattern is
expected underneath this pattern, with diurnally-driven convection
leading to thunderstorms each afternoon across the area. Dewpoints
in the low to mid 70s and precipitable water values increasing to
1.8 to 2 inches will be sufficient to warrant scattered to numerous
coverage across the area each day, with PoPs ranging from 40-65
percent across the area each afternoon.

Aside from high temperatures in the 80s in the higher elevations of
far northeast Georgia, highs will mainly be in the mid to upper 90s
on Friday afternoon. These highs will climb by a degree or two each
day under the influence of the ridge. Furthermore, these highs,
combined with the aforementioned dewpoints in the 70s, will
contribute to heat index values in the triple digits across the
majority of the forecast area through the weekend. Many locations,
particularly in east-central Georgia, could see heat indices in
excess of 105 which would warrant heat headlines each day.

Sunday night into Monday, a low pressure system over southeast
Canada will extend a weakening cold front into the Tennessee
Valley region, which will provide a focus for thunderstorms as it
advances southward through the forecast area. While dewpoints may
briefly drop into the 60s in north Georgia behind the frontal
boundary on Monday and Monday night, it does not look like there
will be substantial change in the airmass otherwise. Hot, humid
conditions and diurnal thunderstorms will nonetheless persist
through the end of the period.

King

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 113 PM EDT Wed Jun 26 2024

VFR conditions will persist into tonight with FEW/SCT cu in the
6-9 kft range. Some potential for at least sct MVFR will increase
after 12-15Z Thursday, particularly for ATL area sites. SHRA
potential also increases after 12Z with SCT SHRA/TSRA coverage
expected to be highest after 18Z Thursday. Winds will remain W to
SW through the period at 4-8 kts.

//ATL Confidence...18Z Update...
Medium confidence on Thursday morning cigs and precip timing
Thursday.
High confidence on other elements.

RW
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&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Athens          74  94  72  93 /  10  50  40  40
Atlanta         75  93  75  94 /  20  60  30  40
Blairsville     68  86  68  87 /  20  50  20  50
Cartersville    71  92  71  94 /  20  50  20  40
Columbus        75  94  74  96 /  20  60  50  40
Gainesville     74  91  74  91 /  20  50  30  40
Macon           73  96  73  96 /  10  60  40  40
Rome            73  93  73  95 /  30  50  20  40
Peachtree City  72  93  71  95 /  20  60  30  40
Vidalia         76  98  74  97 /  20  60  40  60
-- End Changed Discussion --

&&

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

$$

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