Area Forecast Discussion
Issued by NWS Atlanta, GA

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434
FXUS62 KFFC 170604
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
104 AM EST Wed Jan 17 2018


.UPDATE...

06z Aviation update below.

Baker

&&

.PREV DISCUSSION... /Issued 704 PM EST Tue Jan 16 2018/

PREV DISCUSSION... /Issued 604 PM EST Tue Jan 16 2018/

UPDATE...

Wintry mix making its way across north GA this early evening.
With temperatures quickly dropping behind the cold front (which is
currently situated across NE GA down through the metro, south to
Columbus), expect a fine line between rain/snow as the
precipitation continues to move south and east. Thus expecting the
far northern tier of GA to see mainly snow over the next hour,
transitioning down to the metro between 7pm and 9pm. This
transition of rain to snow will continue to slowly move toward
Columbus around midnight, to Macon around 5am.

An area of concern is the possible mesoscale banding that could
set up across a portion of the area later this evening into the
overnight. This is due to the positively tilted trough, exiting
jet and low/mid level impulses allowing lift to be more enhanced.
This combined with fgen features showing a bit of instability
could result in localized higher snowfall amounts. Based on this
information and current model trends, current thinking is that
this region would be between LaGrange down toward Columbus then
northeast toward Athens.

We will continue to monitor observations and high resolution model
guidance and update as needed.

26

&&

.PREV DISCUSSION... /Issued 226 PM EST Tue Jan 16 2018/

SHORT TERM /Tonight through Wednesday Night/...
Models in pretty good agreement with the current system moving
across the Southeast U.S. There are some differences in the snow
amounts but all agree that the area moving across north Georgia will
weaken as frontogenesis develops across southern/central AL and into
central GA. This will enhance the snow amounts across central
Georgia tonight and for this reason we have extended the Winter
Weather Advisory eastward across central Georgia tonight. As for
snow amounts, a band of heavier snow will set up across central
Georgia but as to the exact location this is difficult to pin point.
And since this is a fast moving clipper amounts will be limited.
Have generally gone with up to 2 inches. Downsloping immediately
southeast of the mountains will aid in keeping snow amounts lighter.

The snow will move out of the CWA by Wednesday morning however
northwest winds will become strong and gusty. Black ice could be an
issue across north and central Georgia Wednesday morning and for
this reason we have extended the Winter Weather Advisory until 10 AM
Wednesday.

With the cold temperatures wind chills are expected to drop into the
advisory category and therefore will maintain the wind chill
advisory across north Georgia. Will also mention the strong gusty
winds in the wind chill advisory as well as state a wind advisory
may be needed for Wednesday.

17

&&

.LONG TERM /Thursday through Tuesday/...
No changes made to the long term portion of the forecast.

NListemaa

The previous long term discussion is below...

A deep trough will be moving off the east coast at the start of the
period with a transition to a northwest to west flow aloft. A very
dry air mass will spread over the forecast area and persist until
late in the weekend. GFS/ECMWF in general agreement of an increase
in moisture on Sunday as high pressure moves off the east coast and
low level winds become southerly. A strong short wave moving through
the upper MS Valley late Sunday into Monday will push a cold front
through north and central GA on Monday. Pops will increase across
the area Sunday into Monday. A strip of low CAPE approaches the west
central counties on Monday and isolated thunder is not out of the
question...but for now have kept the mention of thunder out.

41

&&

.AVIATION...
06Z Update...
IFR/MVFR cigs and VSBYs with continued bands of -SN along strong
cold front pushing SEWD this morning. SN could restrict VSBY down
to 2SM at times so continued tempo groups of lower IFR within
predominant MVFR. SN should push SE of near KATL after about 10z
(slightly later for other sites) and then quickly scatter/lift,
though enhanced NW winds will kick in for the rest of the day
today. Expecting 14-18 kts gusting up to 30 kts, which may end up
in Wind Advisory levels.


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

Baker

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          34  19  47  26 /  10   0   0   0
Atlanta         29  19  42  25 /  10   0   0   0
Blairsville     25  12  43  19 /  10   0   0   0
Cartersville    28  16  42  21 /   5   0   0   0
Columbus        33  21  47  25 /  10   0   0   0
Gainesville     30  19  44  26 /  10   0   0   0
Macon           36  20  47  24 /  40   0   0   0
Rome            29  16  43  20 /   5   0   0   0
Peachtree City  31  18  44  23 /  10   0   0   0
Vidalia         40  24  48  28 /  30   0   0   0

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM EST this morning for the
following zones: Baldwin...Banks...Barrow...Bartow...Bibb...
Bleckley...Butts...Carroll...Catoosa...Chattahoochee...
Chattooga...Cherokee...Clarke...Clayton...Cobb...Coweta...
Crawford...Crisp...Dade...Dawson...DeKalb...Dodge...Dooly...
Douglas...Fannin...Fayette...Floyd...Forsyth...Gilmer...
Glascock...Gordon...Greene...Gwinnett...Hall...Hancock...
Haralson...Harris...Heard...Henry...Houston...Jackson...Jasper...
Jefferson...Johnson...Jones...Lamar...Laurens...Lumpkin...
Macon...Madison...Marion...Meriwether...Monroe...Morgan...
Murray...Muscogee...Newton...North Fulton...Oconee...
Oglethorpe...Paulding...Peach...Pickens...Pike...Polk...
Pulaski...Putnam...Rockdale...Schley...South Fulton...Spalding...
Stewart...Sumter...Talbot...Taliaferro...Taylor...Towns...
Troup...Twiggs...Union...Upson...Walker...Walton...Warren...
Washington...Webster...White...Whitfield...Wilcox...Wilkes...
Wilkinson.

Wind Chill Advisory until 8 AM EST Thursday for the following
zones: Dawson...Fannin...Gilmer...Lumpkin...Pickens...Towns...
Union...White.

Wind Chill Advisory until 1 PM EST this afternoon for the
following zones: Bartow...Carroll...Catoosa...Chattooga...
Cherokee...Clayton...Cobb...Coweta...Dade...DeKalb...Douglas...
Fayette...Floyd...Forsyth...Gordon...Gwinnett...Hall...
Haralson...Harris...Heard...Henry...Meriwether...Murray...North
Fulton...Paulding...Pike...Polk...Rockdale...South Fulton...
Spalding...Troup...Walker...Whitfield.

&&

$$

SHORT TERM...01
LONG TERM....NListemaa
AVIATION...Baker



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