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Area Forecast Discussion (AFD)

Issued by Peachtree City, GA (FFC)

FXUS62 KFFC 181142

Area Forecast Discussion
National Weather Service Peachtree City GA
742 AM EDT Mon Jun 18 2018

.PREV DISCUSSION... /Issued 347 AM EDT Mon Jun 18 2018/ 

SHORT TERM /Today through Tuesday/...
A 07z analysis of the larger scale pattern reveals a longwave trough 
roughly centered near the OR/NV/ID borders and a ridge located 
downstream of this trough over much of the eastern US. Stronger belt 
of westerly flow exists across eastern Canada...with some of this 
flow extending down towards the northern Great Lakes. Near the 
sfc...a slow moving cold front extends southwestward from a sfc 
cyclone centered across eastern Canada into the northern GL and 
Central Plains. High pressure exists across much of the Southern 
US...with a weak trough noted east of the Appalachians.

Given the synoptic setup described above... a ridge in place in the 
mid/upper levels over Georgia suggests little excitement in the 
sensible weather pattern. Nonetheless...a weak low is found trapped 
under the ridge just to the west of the area across AL/MS /water 
vapor displays this nicely this morning/. This low is expected to 
retrograde west so do not expect it to play much role across 
Georgia. Still...plenty of moisture remains entrenched under the 
ridge in the lower to mid levels which should help spark isolated to 
scattered afternoon/evening convection. Weak vorticity noted at 
700mb along with persistent weak sfc troughing may assist in 
additional forcing across a portion of the CWA later...tho 
confidence is low where/if this will occur. Given weak flow...any 
thunderstorm activity will be slow moving and could pose a threat 
for locally heavy rainfall and decent downbursts /suggested by 
NAM/RAP/HRRR forecast sounding structure with steep lower level 
lapse rates/. Convection should wind down after sunset.

Somewhat better ridging centered over Georgia on Tuesday as western 
US trough dampens and pushes east into the Montana vicinity. This 
should prevent afternoon convection from becoming 
widespread...however given stagnant moisture in the low-mid 
levels...ridging can't completely eliminate thunderstorm 
development. Temps thru the short term will be hot and muggy with 
highs in the lower to mid 90s accompanied by 70s dewpoints.


LONG TERM /Tuesday Night through Sunday/...
Through the week, broad upper level ridge remains the dominant
feature, with trapped moisture at the lower levels keeping diurnal
convection a pesky problem. Have continued chance pops through
Thursday, with the main concern being scattered thunderstorms and
heavy rain potential. 

Ridge weakens through the latter half of the week as shortwave 
approaches the area. Enhanced moisture moves into the region by 
late Thursday as the upper level feature nears and travels across
portions of the Tennessee Valley. PoPs increase Friday and early
Saturday, but model solutions continue to show better moisture
shifting north of the area later Saturday. Seasonal pops return
behind the upper level trough as the axis shifts east of the area

Wednesday through Friday remain warm, and with high relative
humidity over the region, portions of central and eastern Georgia
could see heat index values in the low 100s. At this time these
values are below the Heat Advisory Criteria, but anyone with
outdoor activities should stay weather aware. Those spending
prolonged periods of time outdoors should take frequent breaks and
stay hydrated. 



12Z Update...
Patchy fog around the area has shown up in CSG and MCN obs this
morning. Expect fog to begin to burnoff in the next hour or
so. MVFR/low cigs did not really materialize this morning over 
TAF sites /except CSG with LIFR/. After a few hours of generally 
clear skies this morning...afternoon cu field should develop and 
persist thru the evening at 4-5kft. In addition...isolated to 
scattered convection will be possible in conjunction with peak 
heating. A TEMPO has been included at all sites thru 00z. Winds 
will remain on the west side under 10kts through Tuesday...tho not
entirely impossible to see an ob or two at NE. Do not expect this
to cause any impacts.

//ATL Confidence...12Z Update...
High on all elements.



Athens          93  72  95  73 /  30  20  30  20 
Atlanta         91  74  93  75 /  30  20  30  20 
Blairsville     88  66  88  67 /  30  20  30  20 
Cartersville    92  71  93  71 /  30  20  30  20 
Columbus        91  74  94  75 /  30  20  30  20 
Gainesville     91  72  92  73 /  40  20  30  20 
Macon           91  72  94  74 /  30  20  30  20 
Rome            92  72  93  72 /  30  20  30  20 
Peachtree City  91  71  93  72 /  30  20  30  20 
Vidalia         91  73  94  75 /  40  20  30  20 




SHORT TERM...Kovacik