Area Forecast Discussion
Issued by NWS Atlanta, GA

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451
FXUS62 KFFC 221533
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
1033 AM EST Sun Jan 22 2017

.UPDATE...
Have made several updates to the forecast grids this morning to
account for the latest in model trends and overall thinking. Here
are a few of the key changes:

Morning lull period a bit more defined than previously expected,
so have dropped pops significantly through the late morning hours.

Onset of next round of storms faster than the previous model
solutions were suggesting. Have gone with a faster onset time with
the pops and adjusted to keep the highest pops farther south.

Winds Monday look to be higher than originally forecast, so have
made some adjustments to the wind speeds. The new values meet
advisory criteria, and have gone ahead with a Wind Advisory for 1
AM to 7 PM Monday. The Wind Advisory highlights the risk of non-
convective wind speeds of 20 mph or wind gusts of 35 mph or
higher. We can expect to see strong, gusty winds with storms
today, but the Wind Advisory is for winds due to the tight
pressure gradient following the main storm threat timeframe. It is
possible that north Georgia could continue to see high, gusty
winds after 7 PM Monday, and adjustments to the Advisory area may
be necessary.

Any other significant changes will be made as necessary as new
model data becomes available. A high risk for severe storms has
been issued for portions of central Georgia, with moderate risk
and slight risk areas including another large portion of the
state. This continues to be a concerning situation, with damaging
winds, potential long-track tornadoes, large hail, and localized
flash flooding still being the main hazards. With many events
occurring today in and around the area, please stay alert to
weather watches, warnings, and advisories through the day.

31

&&


.PREV DISCUSSION... /Issued 640 AM EST Sun Jan 22 2017/

SHORT TERM /Today through Monday/...

The second round of showers and thunderstorms are continuing this
morning. Best instability remains central and south at this time as
the warm front lingers south of Columbus to Vidalia. Currently have
a tornado watch for the last county row of our forecast area and
southward. Main upper system will drop into the lower MS valley this
afternoon and continue into the southern Appalachians tonight. Strong
dynamics are associated with this system and could overcome any
lingering stable air from previous showers. So another round of
possible severe storms is expected for this afternoon and into the
evening. The closed upper low will continue to push across the
Appalachians on Monday with extensive wrap around clouds and
showers through most of the day.

The flash flood watch will continue as is for north and central
GA. Additional storms with heavy rain are possible at any point
in the forecast area.

41

LONG TERM /Monday Night through Saturday/...

Minimal changes made to the extended forecast grids. Region gets back
to more seasonal temperatures but should remain dry after mid-week
system passes.

20

AVIATION...
12Z Update...
Short wave moving east with showers and thunderstorms diminishing.
Ceilings still varying from ifr to mvfr and some vfr. the general
trend should be an improvement to mvfr with some vfr during this
lull in the showers. Another round of showers and thunderstorms
expected this afternoon and evening. Winds varying around 180 but
think they will be more southeast this morning and become more
southwest by afternoon ahead of the surface front.

//ATL Confidence...12Z Update...
Medium confidence on all elements.

41

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          68  48  60  41 /  90  70  40   0
Atlanta         66  49  56  40 /  90  70  40   5
Blairsville     61  45  51  37 /  90  90  70  30
Cartersville    67  47  55  39 /  90  80  50   5
Columbus        71  50  60  40 /  70  50  30   0
Gainesville     65  48  57  40 /  90  80  50  10
Macon           72  49  61  41 /  80  50  40   0
Rome            67  48  56  38 /  90  90  40   5
Peachtree City  68  47  57  38 /  80  70  40   0
Vidalia         76  51  64  44 / 100  50  20   0

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 PM EST this evening 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...Emanuel...
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...Montgomery...
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...Telfair...
Toombs...Towns...Treutlen...Troup...Twiggs...Union...Upson...
Walker...Walton...Warren...Washington...Webster...Wheeler...
White...Whitfield...Wilcox...Wilkes...Wilkinson.

Wind Advisory from 1 AM to 7 PM EST Monday 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...Emanuel...
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...Montgomery...
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...Telfair...
Toombs...Towns...Treutlen...Troup...Twiggs...Union...Upson...
Walker...Walton...Warren...Washington...Webster...Wheeler...
White...Whitfield...Wilcox...Wilkes...Wilkinson.

&&

$$

SHORT TERM...31
LONG TERM....Baker
AVIATION...31



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