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FXUS62 KFFC 211917

Area Forecast Discussion
National Weather Service Peachtree City GA
317 PM EDT Mon Oct 21 2019

.SHORT TERM /Tonight through Tuesday Night/...

To begin the short-term period, north and central Georgia remain 
under a southwesterly flow pattern aloft, with an upper level 
longwave trough approaching the area from the west. At the surface, 
a low pressure system will continue to move northeastward from the 
northern High Plains towards the Great Lakes region. A southwest to 
northeast oriented cold front extends from this system into the 
southeastern CONUS and is currently located near the border of 
Mississippi and Alabama, continuing its eastward move towards the 
forecast area. High temperatures across the area this afternoon will 
reach into the 70s across north Georgia and into the low to mid 80s 
across central Georgia. 

Chances for showers and thunderstorms will increase during the mid-
afternoon over northwest Georgia and progressively increase 
southeastward across the area during the overnight period as the 
front moves into the forecast area. While instability associated 
with this system is anticipated to be fairly limited, 0-1 km low-
level shear will be enhanced to 20-30 kts ahead of the front and 0-6 
km bulk shear values could approach 60 kts. This indicates the 
likelihood of an organized line of thunderstorms ahead of the cold 
front, with stronger storms embedded within the line capable of 
producing strong to damaging wind gusts. There is also a slight, but 
non-zero chance for a brief spin-up tornado embedded within the 
line, as well. 

Gulf moisture spreading over the area this morning and early 
afternoon has allowed dewpoints to climb into the mid 60s and will 
continually increase precipitable water values to about 2 inches 
ahead of the front. Rainfall totals are trending lighter than the 
previous forecast and are not anticipated to be overly impressive, 
ranging from about a quarter of an inch in central Georgia and an 
inch in northwest Georgia. Regardless, it is possible that some 
stronger storms within the line could produce locally heavy 
rainfall, particularly across far north Georgia where precipitation 
chances are expected to be highest.

The cold front will then clear the area during the day on Tuesday, 
with the the front and associated precipitation clearing completely 
by late Tuesday afternoon. Slightly elevated northwesterly winds and 
cooler and drier air can be expected in the areas behind the front 
throughout the day on Tuesday, with high temperatures in the 60s in 
north Georgia and in the 70s in central Georgia and overnight low 
temperatures dropping into the 40s across the area.


.LONG TERM /Wednesday through Monday/...

No major changes made to the extended forecast. Things begin with 
high pressure working into the southeastern U.S. with a cold NW 
drainage flow. This will allow for temps to fall into the upper 30s 
for the NE mountains and lower 40s elsewhere across North GA. There 
will be 5 to 7 degrees of dewpoint depression but could still see 
some patchy frost given light winds.

The high will remain the dominant feature through Thu afternoon
although airmass will modify slightly from upper 60s on Wed to
around 70 for Thu afternoon. 

After this, it will be a squeeze play for the local area as
northern stream upper level energy slides into the central plains
while gulf energy moves in from the SW. This will allow for a
combination of upper energy forcing and isentropic forcing to
produce likely pops. Should these trends continue with subsequent
forecasts, these pops will need to be increased to categorical.
Looks like the higher pops will stick around for awhile with no
quick frontal progression. Significant clearing not anticipated
until the very end of the extended period when high bridges over
the area for Sunday.



18Z Update...
Primarily VFR conditions are in place across the area as the period 
begins, with scattered low clouds. Ceilings will lower to MVFR 
during the overnight period between 03-05Z. SHRA with some possible 
TSRA also anticipated to begin between 03-05Z as a cold front moves 
east across the area, and will remain until tapering off by 12Z. IFR 
ceilings and fog with visibility restrictions of 3-4 SM are expected 
beginning at 08Z and remaining until visibilities improve and 
ceilings lift to MVFR by 11-12Z. SE winds at 6-10 kts through the 
afternoon and evening will shift to SW by 08Z and NW at 11-12Z 
Tuesday after the frontal passage. Winds will increase to 10-15 kts 
with gusts to 20 kts by Tuesday afternoon after 18Z.

//ATL Confidence...18Z Update...
Medium confidence on all elements.



Athens          63  74  45  70 /  70  50   0   0 
Atlanta         60  70  46  67 /  70  40   0   0 
Blairsville     54  65  39  62 /  80  40   0   0 
Cartersville    56  70  42  68 /  80  30   0   0 
Columbus        63  74  48  72 /  70  40   0   0 
Gainesville     60  70  45  67 /  80  40   0   0 
Macon           66  76  46  72 /  60  50   0   0 
Rome            56  70  42  69 /  80  20   0   0 
Peachtree City  60  72  44  69 /  70  40   0   0 
Vidalia         69  80  50  73 /  40  40   5   0 




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