498
FXUS62 KFFC 121128
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
628 AM EST Wed Feb 12 2025

...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Thursday)
Issued at 331 AM EST Wed Feb 12 2025

Wedge front is currently situated across much of north and central
portions of the state. A wave of low pressure will move east along a
warm front across the southern Gulf Coast states early this morning.
A second wave of low pressure, dragging a cold front is expected to
move through the CWA late tonight into early Thursday. The front
should make it south of the CWA by late Thursday afternoon. High
pressure and drier conditions will quickly build in behind the cold
front.

The main forecast dilemma for today is the wedge front and how much
erosion will occur on the southern/southwestern edges. BL winds are
still unfavorable for much of the day for wedge erosion. There could
be some northern progress between a MCN to CSG line to the I-20
corridor.

There are two main consequences if the wedge erodes more than
currently forecast for today:

1) MaxT values mainly south of the ATL metro will likely be too low.

2) Any storms that develop or move into the area could become
surface based. This would increase the chances for strong to
potentially severe thunderstorms. This would be most likely within
areas that see more breaks in the clouds (heating). -> For now,
forecasting minimal wedge erosion from where it is currently
situated. Doesn`t mean thunderstorms won`t occur, but they should
mainly be elevated.

Wedge erosion will be more likely as the cold front approaches the
CWA overnight. BL winds become much more favorable for a northward
progression of the warm front. The mountains, as usual, will
probably hang completely within the wedge until FROPA. Temperatures
will rise overnight on the south side of the retreating wedge.

Rainfall amounts early this morning will serve to help saturate the
soils. Another round of rainfall is expected beginning late this
afternoon and lasting through early Thursday...ahead of and along
the cold front. With PWATs well above normal (actually near daily
max values) there will be plenty of tropical moisture available.
There is also a lot of lift in the upper levels associated with the
system, so it will be a VERY EFFICIENT rainfall producer. With
saturated soils, there is definitely increased potential for
flooding on creeks, streams and rivers. In addition, localized flash
flooding will also be possible.

NListemaa

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 331 AM EST Wed Feb 12 2025

Surface high pressure will be moving into the forecast area at the
start of the long term (Thursday night) and taking up residence
across the eastern CONUS on Friday. This will result in dry weather
conditions to the end the work week. The surface high quickly
departs off the East Coast and another CAD wedge is forecast to
develop in northeast GA early Friday night into early Saturday. A
mid-level trough will dig across the western CONUS and track across
the ArkLaTex Saturday into Sunday. At the surface, a low pressure
system and attendant cold front will bring a final round of rain and
a conditional severe threat Saturday Night into Sunday. Rain chances
will start to increase on Saturday as a warm front lifts northward
and becoming more widespread overnight into Sunday along and ahead
of the cold front. The surface low and upper level support lifts
quickly to the NNE on Sunday while the cold front moves through and
rain chances gradually coming to an end. Thinking this is a reason
why forecast rainfall amounts came down a tad from the previous
forecast. Following this weekend system, surface high pressure moves
back into the region with quasi-zonal flow aloft. Thus we welcome
another period of dry weather and pleasant temperatures on Monday
lasting until midweek.

Weekend Severe Potential: Similar to the Wednesday/Thursday, the
more favorable timeframe for thunderstorms, potentially severe
thunderstorms will be Saturday Night into early Sunday. As we know,
nighttime severe weather can be especially hazardous, so remain
weather aware. As of this update, SPC maintains a 15% severe outlook
area for west GA on Saturday that is largely unchanged from the
previous forecast update. Uncertainties in the severe potential
still remain. What we know: The convective mode would likely be
linear owing to the high shear/low CAPE environment. Thus, isolated
damaging winds and/or embedded spin up tornadoes could form within
any kinks or breaks in the line. The area highlighted by the 15%
severe risk (NW/W GA) will be in relatively close proximity to the
surface low and better upper level forcing. The CAD wedge may limit
severe potential for areas east of the ATL metro. What we don`t
know: How much instability will be able to materialize at the
surface? Does the lingering CAD wedge inhibit convective
development?

Weekend Rain and flooding chances: Depending on how much rainfall we
receive between through Thursday will determine the flood risk
through the weekend and how rivers/streams respond. Though as we
enter the weekend, rivers are likely to still be elevated with soils
across the North still quite saturated. As previously mentioned,
forecast rain totals and probabilities have come down slightly since
the previous update. Last rainfall totals Saturday through Sunday
north of I-20/I-85 corridor ranges from 1 to 1.75 inches with
isolated up to 2 inches at the higher elevations. NBM probabilities
of greater than 1 inche of rainfall for this same region by Monday
morning range from 70% to 90% -- the higher end probabilities in far
north GA and at the highest elevations. Greater than 2 inches for
North GA only still range from 45 to 50%. So while less `heavy`
rainfall with this system overall it may still be significant given
antecedent soil conditions particularly up in North GA. WPC has
painted a Marginal Risk (Level 1 of 4) for areas north of I-20/I-85
for heavy rainfall on Saturday.

Long Term Temperature Overview: Seasonal temperatures are forecast
for Friday with highs in the mid 50s to 60s and lows in the mid 30s
to mid 40s. Saturday and Sunday look to be the warmest days in the
period at least for parts of Central GA with highs ranging in the
mid 50s to the north and mid/upper 70s across the south. We cool off
at the start of the work week with morning lows on Monday in the 20s
and 30s with forecast highs in the 40s and 50s and rebounding back
into the 50s and 60s by Tuesday.

07

&&

.AVIATION...
(12Z TAFS)
Issued at 612 AM EST Wed Feb 12 2025

Cigs likely will bounce between 004-005 much of the day in
widespread on/off rain. The heaviest rainfall is expected
overnight with a frontal passage along with a chance for thunder.
Quickly improving conditions behind the front. A wind shift to the
west side is likely around 11Z THU.


//ATL Confidence...12Z Update...
Med confidence all elements.
NListemaa

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          44  43  66  32 / 100 100  40  10
Atlanta         49  49  63  33 / 100 100  30   0
Blairsville     45  43  57  23 / 100  90  10   0
Cartersville    47  47  60  27 / 100  90  10   0
Columbus        73  63  72  37 /  90 100  60  10
Gainesville     42  42  63  31 / 100 100  20   0
Macon           66  61  72  37 /  60 100 100  10
Rome            49  47  59  26 / 100  80  10   0
Peachtree City  56  54  66  31 / 100 100  30   0
Vidalia         78  67  75  45 /  20  60  70  10

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday morning for GAZ001>009-011>016-
019>025-030>035-041>048-052>057-066>068.

&&

$$

SHORT TERM...NListemaa
LONG TERM....07
AVIATION...NListemaa