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Area Forecast Discussion (AFD)

Issued by Peachtree City, GA (FFC)

FXUS62 KFFC 180812

Area Forecast Discussion
National Weather Service Peachtree City GA
412 AM EDT Sun Aug 18 2019

.SHORT TERM /Today through Monday/...
To begin the short term period, a broad upper level ridge will be in 
place to the west of the forecast area over the Rockies, the and to 
the east of the area over the western Atlantic. Between these two 
ridges, weak troughing will be developing over the eastern CONUS, 
leading to a transition in the overall pattern over the forecast 
area. The upper-level troughing is allowing for a northward 
advection of the deeper moisture, which will lead to a gradual 
moistening of the airmass and an overall more unsettled pattern. 
PWATs of 1.2-1.4 inches across the area this morning will steadily 
increase to 1.8-2 inches by Monday afternoon. At the surface, a 
dissipating frontal boundary will remain stalled across central 
Georgia through tonight, providing a focus for showers and 
thunderstorms across central Georgia. As such, chance PoPs are 
expected this afternoon and evening in central Georgia with mainly 
slight chance PoPs in north Georgia. 

The persistent upper trough and increase in deep moisture will allow 
for greater coverage of diurnally driven convection during the 
afternoon and evening on Monday, with primarily chance to low-end 
likely PoPs are expected across the area. Widespread severe weather 
is not anticipated on Sunday and Monday, although an isolated strong 
storm could produce gusty winds and frequent lightning. With the 
increased moisture on Monday, there is a possibility that some of 
the stronger thunderstorms could produce locally heavy rainfall, as 
well. Forecast high temperatures are expected to remain above 
climatological normals through the period. Especially along and 
north of the I-85 corridor where highs could range from 5-9 degrees 
warmer than average. Heat index values are anticipated to remain 
below Heat Advisory criteria, but will nonetheless reach into the 98-
103 degree range each day across much of the area with the exception 
of the higher elevations in northeast Georgia.


.LONG TERM /Monday Night through Saturday/...
A pattern change begins in the short term, and continues through
the extended periods. Diurnally enhanced scattered to numerous showers
and thunderstorms will be the norm through day 7. The area will 
remain situated in the weak upper trough between the ridge over 
the Plains and western Atlantic ridge. The over all weather
pattern will provide the boost for afternoon and evening 
scattered shower and thunderstorm development. Precipitable water
values also increase into the 1.7-2.0 inch range beginning Tues 
which will contribute to the potential for locally heavy rainfall 
into next weekend. 

By the end of the week, the models are showing a cold front
pushing south out of the great lake state Thursday and into North
GA Friday. The models show this frontal boundary stalling of the
southeastern U.S. and keeping rain chances across the region
through the end of the forecast period. If this frontal boundary
pushes a little further south into North Fl will will see a much 
drier forecast so will have to keep a close eye on this as we get 
closer to the weekend. As for now, will continue with scattered 
convection each day. 

Temperatures, while tempered somewhat by increased convection, will 
remain above normal through the week. The increased moisture will 
also keep afternoon heat index values from the upper 90s to low



06Z Update...
Mainly VFR conditions are expected throughout the period, with the
exception of the southern TAF sites. Patchy MVFR fog and IFR cigs
are possible over CSG/MCN are possible in the early morning,
beginning at 09Z and improving by around 14Z. A cu field at SCT
040-060 is anticipated to develop after 15Z across the forecast
area. Scattered TSRA is possible in the late afternoon, with a
PROB30 introduced at CSG/MCN where coverage is expected to be
greatest. Wind directions are anticipated to change a couple of
times during the forecast period, with winds shifting to SW in the
early morning hours and back to SE during the late afternoon. 

//ATL Confidence...06Z Update...
Medium confidence on all elements.



Athens          96  72  93  71 /  30  30  50  30 
Atlanta         96  74  93  72 /  20  20  50  30 
Blairsville     89  66  87  65 /  30  20  50  20 
Cartersville    97  72  95  72 /  20  20  40  20 
Columbus        94  74  92  73 /  30  30  60  30 
Gainesville     94  72  92  71 /  30  30  40  30 
Macon           94  73  91  72 /  30  30  50  30 
Rome            99  72  96  72 /  10  10  40  20 
Peachtree City  96  72  93  72 /  30  30  50  30 
Vidalia         92  73  89  72 /  40  30  60  30