156
FXUS62 KFFC 201028
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
628 AM EDT Mon May 20 2024



...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Tuesday)
Issued at 259 AM EDT Mon May 20 2024

As the shortwave to the east makes its grand entrance off the
eastern seaboard, a ridge is beginning to stretch across the Ohio
and Mississippi River Valleys. This ridge will continue to build
in along the spine of the Appalachians through today as a potent
negatively tilted shortwave over the Central Plains skirts off
over the Great Lakes Region. Surface pressure in the leeside of
the Appalachians is already evident in the surface analysis where
that is expected to strengthen thanks to the synoptic-scale
subsidence. Easterly flow will develop a southerly component
through the day, allowing the enhancement of the upslope winds
across the northeast Georgia mountains. With considerable moisture
remaining in the low levels of the atmosphere, SBCAPE between
500-1000 J/kg in northeast Georgia, and steep low level lapse
rates, a few orographically induced storms could initiate off of
mountainous terrain. The far northeast Georgia mountains are the
only locations in the CWA that are forecast to see any chance at
precipitation this afternoon as well as any meaningful cloud
coverage. Most locations today will see mostly sunny skies and
high temperatures topping out in the low to mid 80s with higher
elevations in the 70s. Overnight, enhanced cloud coverage from
modest moisture aloft across north Georgia will keep temperatures
from dropping much below the mid 60s, even in areas of higher
elevations where temperatures are forecast to bottom out in the
upper 50s. Areas further south across central Georgia will see low
temperatures closer to the 60 degree mark thanks to clear skies
allowing for longwave radiation to cool the surface more
efficiently.

Tuesday, a seasonably warm and sunny day is forecast for the
forecast area. Despite winds out of the southeast, surface moisture
is lacking, thus limiting chances for orographically induced showers
and thunderstorms across northeast Georgia again. Have maintained a
low end slight chance for precipitation across extreme northeast
Georgia as some moisture remains around the 850mb level. Otherwise,
dry conditions are anticipated areawide. Maximum daily temperatures
will climb into the mid to upper 80s areawide outside of elevated
terrain, where temperatures will remain in the 70s.

KAL

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 259 AM EDT Mon May 20 2024

The long term period begins with a longwave ridge across much of the
eastern CONUS. This ridge will extend from the northwest Gulf of
Mexico into the Deep South and then northeastward towards New
England. Surface high pressure associated with this ridge will be
centered to the northeast of the forecast area. Subsidence
underneath this high will largely serve to inhibit precipitation
through Wednesday. With increasing 1000-500 mb thicknesses under the
ridge combined with plenty of sunshine, a warming trend will
continue on Wednesday. After starting the morning in the low to mid
60s across the majority of the area, high temperatures on Wednesday
afternoon are forecast to rise into the upper 80s. Temperatures will
be locally cooler in the higher elevations of far northeast Georgia.

While weather conditions will be benign across north and central
Georgia on Wednesday, a deepening upper low will be moving from the
upper Midwest towards the Great Lakes region. The axis of the ridge
will meanwhile clear Georgia to the east by late Wednesday, at which
point southwesterly upper flow between the low and the ridge will
enter north Georgia, leading to increasing atmospheric moisture. As
the low pressure system becomes occluded and moves into southeast
Canada, a cold front will advance slowly southward into the
Tennessee Valley region by Wednesday night. Isolated to scattered
showers and thunderstorms will begin to advance into far north
Georgia by early Thursday morning as a weak disturbance traverses
the upper-level flow and overruns the frontal boundary. PoPs on
Thursday and Thursday night will mostly be confined to far north
Georgia, with low-end chance PoPs in the far northern tier and and
progressively lower chances to the south. Even in spite of increased
cloud cover across far north Georgia near the front, the warming
trend will persist, with highs forecast to be in the upper 80s in
north Georgia and low 90s in central Georgia. These high
temperatures will be consistent with what can be expected for the
remainder of the week and into the weekend, which will run about 4-8
degrees above climatological normals.

As the low continues to move away to the northeast, the frontal
boundary will become more elongated from west to east, and its
southward advance will begin to slow. By Friday morning, the frontal
boundary is forecast to stall near the Georgia/Tennessee state line.
A more robust shortwave will traverse the westerlies and from the
Lower Mississippi River Valley across the Southeast on Friday into
Friday night. This setup is likely to bring more numerous showers
and thunderstorms to the forecast area on Friday, especially where
wave overruns the stalled frontal boundary, providing a focus for
additional convection. Uncertainty still remains in the model
guidance with respect to the strength and exact position of this
disturbance, which will influence where the most widespread
precipitation will occur. While the frontal boundary will begin to
dissipate by early Saturday morning, additional disturbances will
continue to traverse the westerlies and through the Southeast this
weekend. Scattered showers and thunderstorms are thus expected on
both Saturday and Sunday, with the highest chances during the
afternoon each day where diurnal instability will be greatest.

King

&&

.AVIATION...
(12Z TAFS)
Issued at 622 AM EDT Mon May 20 2024

VFR conditions through TAF cycle. Cumulus field will develop
around 14Z with FEW040-050 through the afternoon before becoming
FEW250 overnight. Light E/SE winds at 5KT or less throughout TAF
cycle becoming calm to VRB03KT during the overnight hours. Cumulus
field returns tomorrow during the afternoon at KATL.

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

KAL

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          60  86  60  87 /   0   0   0   0
Atlanta         64  86  64  87 /   0   0   0   0
Blairsville     59  80  57  83 /  10  10   0   0
Cartersville    63  87  62  88 /   0   0   0   0
Columbus        63  86  63  88 /   0   0   0   0
Gainesville     63  85  62  86 /   0   0   0   0
Macon           60  85  61  88 /   0   0   0   0
Rome            62  87  62  88 /   0   0   0   0
Peachtree City  60  86  61  88 /   0   0   0   0
Vidalia         62  85  62  88 /   0   0   0   0

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...KAL
LONG TERM....King
AVIATION...KAL