Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 210538

Area Forecast Discussion...Updated for Aviation
National Weather Service Peachtree City GA
135 AM EDT Sat Apr 21 2018

.PREV DISCUSSION... /Issued 248 PM EDT Fri Apr 20 2018/

SHORT TERM /Tonight through Saturday Night/...
Another quiet weather day across the area as weak shortwave ridging
builds into the region. In the lower levels...high pressure
continues to build into the area in the wake of yesterday`s frontal
system. Altho CAA has subsided...a cooler airmass resides across the
state today with high temps topping off in the 60s and 70s under
clear skies. Tranquil conditions will persist thru the overnight
hours...tho moisture will begin to slowly increase from the south.

For main center of the sfc high moves into the eastern
Great Lakes region...weak wedge will develop along the eastern side
of the Appalachians. The leading edge of the wedge frontal boundary
will kick wind speeds up /10-15mph sustained/ by mid morning where
they will continue into the late afternoon. Periodic gusts will be
possible for areas nearest the actual boundary. As this occurs
across our area...a glance upstream reveals a notable sfc low
developing in the vicinity of the west Texas terrain as a strong
closed low moves into the Southern Plains. This low should have no
problem rapidly pulling rich theta-e air north across the western
Gulf region. This system will be enroute to the local area Saturday
night and into the long term where POPs will quickly be on the
increase. Given stable conditions across Georgia overnight
Saturday...have not included thunder potential.


LONG TERM /Sunday through Friday/...
No major changes to the long term. A wet period can still be
expected with the greatest rain amounts later Sunday through
Monday night.


Active fcst period on tap with the main player being the influence
of a slow moving closed low from the west interacting with a
classical CAD wedge from the northeast Sunday through early
Tuesday. The two features will result in persistent moisture
overrunning and widespread continued shower development. Will need
to watch for flooding concerns given some higher QPF trends
(generally 2-4 inches). Included Hydrology section below. Thinking
that the heaviest amounts will end up being where the wedge front
meanders (northern central GA into eastern north GA), which for
now looks to match up in the orientation of the max storm total
QPF. Enough progged instability present at least for Monday
afternoon to include slight thunder mention confined for still the
southern tier.

Kept some pops in for the northern majority of the CWA for Tuesday
into Wednesday as the trough starts to lift northward as it
dampens into the other longwave energy, then guidance has less
consensus on timing and amount of moisture present with several
other potential shortwaves/fronts for Thurs/Fri. Will need to see
more agreement to warrant much higher than slight pops at the

Temps below normal thru period with coolest days on Sunday thru
Tuesday given aforementioned wedge and precip. North GA should
have limited diurnal range from the mid/low 50s to mid/low 60s.


The local area will be in a transition period thru
Saturday night as moisture is expected to gradually increase from
south to north thru the period ahead of the next major weather
system. Thru the day on Saturday...dewpoints are expected to
increase from the upper 30s into at least the 40s which corresponds
to RH values above fire danger criteria. In addition...a weak wedge
front will build into the area. Given persistently dry fuels...could
have localized areas meeting high fire danger criteria Saturday
afternoon where moisture return is slowest or where winds become
elevated near/along the wedge front. Given isolated nature of
this...have opted to not issue a Fire Danger Statement

Conditions will continued to be monitored for heavy rainfall
potential, most so Sunday night and Monday. The area could receive
amounts of 2 to 4 inches Sunday through Monday night. A flood or
flash flood watch could be needed with future forecasts.


06Z Update...
Clear skies will start this TAF set with increasing clouds toward the
end of the period. As the clouds move in after 00z Sunday...expect
them to stay VFR. Winds will remain on the east side. Expect speeds
10kt or less through 12z then increasing into the 10 to 15kt range
by 14-15z today.

//ATL Confidence...06Z Update...
Confidence high on all elements.



Athens          42  72  49  66 /   0   0  30  50
Atlanta         46  72  52  64 /   0   0  50  80
Blairsville     39  67  44  61 /   0   0  40  60
Cartersville    43  72  52  64 /   0   0  60  80
Columbus        47  75  56  69 /   0   5  60  90
Gainesville     44  70  49  63 /   0   0  40  60
Macon           44  75  53  69 /   0   5  50  70
Rome            41  73  51  65 /   0   0  60  90
Peachtree City  41  73  51  65 /   0   0  60  80
Vidalia         47  75  55  71 /   0   5  30  50




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