Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 221920

Area Forecast Discussion
National Weather Service Peachtree City GA
320 PM EDT Thu Jun 22 2017

.SHORT TERM /Tonight through Friday Night/...
Main forecast concern will be initially here in the near term as the
environment has shown some rapid destabilization with the extremely
tropical airmass in place as the low cloud deck has been scattering
quickly from the south given being in the warm sector of Cindy`s
remnants. Convective bands streaming in from the south fueled by a
steady strong moisture advection off the Gulf will have about 2000-
3000 J/kg of SBCAPE to attain, albeit tall/skinny in profile. The
issue will be with both the PWATs being close to 2 inches and
enhanced area of helicity rich low levels just starting to impinge
upon the western border of the CWA. Some 250 m2/s2 of 0-1 km SRH
will be bothersome for isolated quick spin-up tornado potential in
our western tier from late afternoon here into the evening. Also
given the aforementioned PWATs, any stronger convection will have
high precip efficiency and training of cells could bring flash flood
potential. It`s not a welcomed sight to see temps of upper 80s/low
90s over dewpts in the mid to upper 70s advecting into the area.

The deeper moisture field and orientation of Cindy`s dynamics should
continue to phase with an upper shortwave more to the NW by late
tonight into Friday. Expecting a lull in shower/storm coverage
mainly after midnight tonight as chance to likely pops stay more
orientated to the far NW and TN Valley. Could have a similar type of
convective threat for northern portions of the area by Friday
afternoon (given progged instability/low level shear parameters) and
then be more progressive to the SE with the evolution of the
shortwave and translated sfc front late Friday night into Saturday.
Tailored likely to categorical pops with this feature accordingly
across north GA. Will be rather gusty out of the SW ahead of this as

Temp wise, a bit more diurnal range expected Friday with more areas
reaching highs close to climo in the upper 80s to low 90s (less
morning cloud coverage expected).


.LONG TERM /Saturday through Thursday/...
The remnants of Tropical Storm Cindy will finally be out of our hair
at the beginning of the long term forecast period on saturday
morning. However there will be a cold frontal boundary moving south
across the area. Rain and thunderstorms will be ongoing along the
front...enhanced by diurnal heating in the afternoon. There looks to
be enough deep layer shear /0-6km of 20-30kts/ as a broad trough
deepens across the eastern 2/3rds of the US to work in conjunction
with instability invof the front. This should allow for some
organization of thunderstorm clusters along the front. The main
threat will be damaging wind gusts. SPC has a large majority of
central and eastern Georgia in a marginal risk.

The front will make slow progress into central Georgia Saturday
evening into the overnight hours but the loss of daytime heating and
rather poor forcing should allow most activity to gradually
dissipate. Front looks to linger across far southern zones on Sunday
where again diurnal heating should allow for a gradual increase in
thunderstorm activity through the afternoon. Shear appears to be
displaced too far north to pose a notable severe threat by this
time. Can`t rule out isolated stronger storms...but think Saturday
has better parameters than Sunday.

Front should clear the CWA by Monday. A rather unseasonably
strong area of sfc high pressure will gradually build into the
region from the north in the wake of the front...which will make
for a dry day. A strong shortwave rotating around the broad scale
trough over the eastern US will likely bring some clouds to area
on Tuesday...but thinking large dome of sfc high pressure will
keep things dry. Height rises in the mid level behind this
shortwave combined with sfc high pressure should make for a very
pleasant Wednesday. Will see moisture gradually return outside of
the extended as the sfc high begins to scoot off the Atlantic



18Z Update...
Cigs primarily in MVFR to low end VFR range to start this period,
then could see some scattering of higher VFR with isolated to
scattered SHRA/TSRA this afternoon into evening. Some stronger SSE
winds and gusts could be mixed down with areas of scattering as
well or within convection. Have tempo for TSRA mainly from 20-00z
with slight timing differences for most sites. Could again see
overnight with IFR/MVFR cigs and switch to SSW winds mainly after
07-09z for KATL and nearby sites. Should have a lull in precip
overnight into Friday morning (staying more NW of sites). Though
included prob30 for TSRA after 18z Friday at KATL. Wind mags
increase also by then to 11-13 kts with gusts near 20 kts.

//ATL Confidence...18Z Update...
Medium on precip coverage/timing into this evening.
Medium on overnight cig potential lower than MVFR.
High on all else.



Athens          71  90  73  85 /  60  30  60  70
Atlanta         72  87  73  83 /  60  40  70  70
Blairsville     67  83  68  79 /  70  60  80  70
Cartersville    72  87  72  83 /  60  60  80  70
Columbus        74  90  75  86 /  20  20  40  60
Gainesville     70  86  72  82 /  60  40  80  70
Macon           73  91  74  88 /  30  20  30  40
Rome            72  87  72  84 /  60  70  80  70
Peachtree City  71  88  72  84 /  50  30  60  60
Vidalia         75  91  75  91 /  40  20  20  30




LONG TERM....Kovacik
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