Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 202341
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
741 PM EDT Wed Sep 20 2017



.UPDATE...
Have only made minor adjustments to hourly pop and wx grids for
the next few hours as precip persists over portions of central
Georgia. Otherwise, previous forecast looks to be on track.

31

&&

.PREV DISCUSSION... /Issued 328 PM EDT Wed Sep 20 2017/

SHORT TERM /Tonight through Thursday Night/...
As mentioned in previous update, pattern expected to remain mostly
the same during the short term period. Somewhat unusual to see
temps this warm in late September. Isolated convection may become
a little more widespread over all of north and central GA Thursday
afternoon as it has today over middle GA today. Model blends doing
quite well with forecast temps, dewpoints and winds but did
increase PoPs a bit during the afternoon and early evening. Any
tropical systems will remain well to our east.

SNELSON

LONG TERM /Friday through Wednesday/...
A broad ridge pattern and associated surface high pressure over the
eastern CONUS will draw ample moisture from the Atlantic Ocean over
the region to begin the extended period. Impulses within the upper
level flow will provide a focus for diurnally driven showers and
thunderstorms on Friday and Saturday. NAM and GFS models show modest
CAPE values between 1000 and 1500 J/kg in the afternoon on both
days, along with PWATS as high as 1.5 inches which is slightly
above normal for this time of year. PoPs will be highest on
Friday afternoon and are expected to be within the 30 to 40
percent range on Friday afternoon throughout the region.
Additionally, PoPs will be within the 20 to 30 percent range on
Saturday afternoon. High relative humidity between 95 and 100
percent coupled with light winds will lead to widespread patchy
fog across central and northwest Georgia during the early morning
hours on Friday through Sunday.

GFS/ECMWF/NAM/Canadian models continue to agree on Tropical Storm
Jose and Hurricane Maria remaining well to the east of our region.
No direct impact to the region from either tropical cyclone is
expected to occur in the extended period. Maria will pass through
the South Atlantic Ocean on Sunday through Tuesday. At this time the
southeastern CONUS will be influenced by the subsidence zone to the
west of Maria, which will result in a drier and more stable air mass
over Georgia. PoPs will decrease to minimal values from Sunday into
next week. Temperatures will remain above average throughout the
extended period.

KING

NListemaa

&&

.AVIATION...
00Z Update...
Aside from patchy IFR/MVFR vsbys for 10-14z, expect VFR conditions
through the period. NW winds will become NE Thursday. Isolated to
scattered showers and thunderstorms will develop after 16z, and
have included a VCSH at TAF sites for generally after 19z to
highlight best coverage period.

//ATL Confidence...00Z Update...
Medium on timing of wind shift.
High on all other elements.

31

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          67  89  67  85 /  10  20  20  30
Atlanta         69  88  69  85 /   5  20  20  30
Blairsville     60  83  62  80 /   5  30  30  40
Cartersville    65  88  67  86 /   5  20  20  40
Columbus        71  91  70  88 /  10  20  20  30
Gainesville     67  86  67  83 /  10  20  20  30
Macon           68  90  68  86 /  20  20  20  30
Rome            65  89  66  87 /   0  20  10  30
Peachtree City  67  89  67  85 /   5  20  20  30
Vidalia         71  90  70  88 /  20  30  30  30

&&

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

$$

SHORT TERM...31
LONG TERM....41
AVIATION...31



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