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000
FXUS62 KFFC 231956
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
356 PM EDT Wed Aug 23 2017

.SHORT TERM /Tonight through Thursday Night/...

Current surface analysis across the local area indicates frontal
boundary is now moving through the Atlanta metro. Drier air
continues to move in behind this feature with GOES precipitable
water product indicating values only around an inch from Trenton
to Cleveland and 1.3 to 1.5 down to the i20 corridor. This is much
more significant than what models had indicated around 36 hours
ago and attributable to a quicker frontal progression. As a
result, precip coverage has been almost non existent north of the
front and have continued to cut pops with each update with only
isolated coverage in latest iteration.

South of the front is a bit of different story although even
convection here has been sparse and slow to develop. Still believe
there is a good opportunity though to realize higher values in
the high end scattered category with front, subtle shortwave and
PWs over 2 inches. Convective temps were slightly higher today
owing to the later start but now in the 90s, should have no
troubles seeing higher pop values. There are some slightly cooler
values aloft with -7C at 500mb so could see some more robust
updrafts allowing for some isolated strong storms.

The drying trend continues through Thu with PWs dropping well
below an inch across the northern tier...mainly from I20
northward. Still sufficient moisture and instability across far
southern sections for tsra activity but should be only isolated to
low end chance at best. Same cool pool aloft will be in place so
again cannot rule out and isolated strong storm during this time
period. Went with the consensus blend for temps which yield values
2 to 3 degrees lower than today for areas to the north.

Deese


.LONG TERM /Friday through Wednesday/...

No major changes to the long term forecast. 12Z guidance not
showing too many changes. With surface ridging over our area, a
tropical low east of the Florida coast, and whatever becomes of
Harvey, the long term forecast is uncertain. Being in the middle
of these three features, we have kept in chances for rain through
the extended, which matches 12Z guidance blend. Previous
discussion follows.

3/SNELSON

PREV LONG TERM DISCUSSION... /Issued 305 AM EDT Wed Aug 23 2017/

LONG TERM /Thursday Night through Tuesday/...
In the early part of the long term, high pressure will continue
to keep north Georgia dry for the rest of the week with low chance
pops continuing across parts of central Georgia. After Friday
confidence in the solution drops as the models struggle with a
solution to the tropical wave moving into the western Gulf and its
effects on the CWA. Will trend to climatology with slight chance
to chance pops each day beginning Saturday and continuing into
Tuesday. Temperatures will be at or just below normals.

17

&&

.AVIATION...
18Z UPDATE...

TSRA has been much less than anticipated this time yesterday as
models continue to dry things out quicker. Hard to even make a
case for VCSH at this point but with front still to the north, we
could still see some development at CSG and MCN. Have chosen to
keep TEMPO in there for now but may need to remove in lieu of
just VCSH should trends continue. Winds will start out NW but
quickly shift to NE by Thu morning. Could come back around to NW
in the afternoon but will not include that shift in the forecast
just yet.

//ATL CONFIDENCE...18Z UPDATE...
High on all elements.

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          69  88  68  87 /  10   0   0   5
Atlanta         70  88  69  87 /  10   0   0   5
Blairsville     60  82  60  81 /   0   0   0   5
Cartersville    65  87  65  87 /   5   0   0   5
Columbus        73  92  71  91 /  20  20  20  10
Gainesville     68  86  67  84 /   5   0   0   5
Macon           72  91  71  90 /  30  20  20  10
Rome            65  87  63  87 /   5   0   5   5
Peachtree City  69  89  67  88 /  10   0   0   5
Vidalia         74  93  73  90 /  40  40  40  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Deese
LONG TERM....3/SNELSON
AVIATION...Deese