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000
FXUS62 KFFC 190608
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
208 AM EDT Fri Apr 19 2024

...New 06Z Aviation Discussion...

.SHORT TERM...
(This afternoon through Friday)
Issued at 238 PM EDT Thu Apr 18 2024

Low confidence pop forecast for overnight and into tomorrow.

Challenging forecast for tonight into tomorrow. The models,
including the hi-res, continue to struggle with the convection near
the ARKLAMISS. The hi-res models do weaken any convection as it nears
the AL/GA state line late this afternoon into the evening hours. Do
think some weakening will occur due to loss of heating, but coverage
of storms may be a bit more than the models are progging. There will
be enough surface instability around through the early evening for
isolated/scattered thunder and the lapse rates remain pretty steep.
Luckily shear remains pretty low. Strong storms are possible with an
isolated severe storm not out of the question, mainly near the
central AL/GA border. Strong storms will be capable of producing
gusty winds and hail.

A break in storms is likely well into the overnight hours. The
models are progging a second round of storms (MCS) potentially moving
in from the NW towards 12Z. There has been some run to run
consistency within the HRRR, but the hi-res models remain all over
the place with the evolution of this system. With such uncertainty
with this system, will refrain from using likely pops and stick to
scattered at this time. However, if models come into better
agreement, pops will have to be adjusted upwards.

A third round of storms is possible again tomorrow as a front sags
south across northern portions of the state. Convective initiation
will be highly dependent upon any morning convection that moves
through. If there is good coverage of storms with the early morning
MCS, then initiation may be later in the day. If the early morning
MCS falls apart near the border, then convective initiation/coverage
should be greater tomorrow afternoon.

With all of this said, the models struggle with these types of
systems...especially the timing. However, if/when convection
fires, it will definitely have the potential to be strong or
severe, especially tomorrow afternoon. CAPE values should be
around 1500 J/kg with steep lapse rates. Shear remains low, but
frontal forcing will be another player. Damaging wind gusts and
large hail would be the primary severe thunderstorm hazards.

NListemaa

&&

.LONG TERM...
(Saturday morning through next Wednesday)
Issued at 238 PM EDT Thu Apr 18 2024

The long-term period picks up on Saturday with 25% to 40% PoPs in
the afternoon and evening, generally along and south of I-20. The
SREF is progging SBCAPE of 800-1200 J/kg across said area, which
indicates the potential for isolated to scattered showers and
thunderstorms. The greatest surface-to-500-mb bulk shear will be much
farther north, so the setup will not be conducive for organized
convection. That said, a few strong to severe storms posing a hail
threat and downburst threat cannot be ruled out. A southern-stream
shortwave trough passage on Sunday will increase the surface-
to-500-mb bulk shear to 40-50 kts, and while the SREF is progging
less instability on Sunday, thinking is that the shortwave will
provide enough lift to warrant a 60% to 80% chance for showers with a
15% to 25% chance for thunderstorms. Again, widespread severe
weather is not expected, but a strong to severe storm or two are
possible. Continuing to message a QPF of ~0.50" to 0.80" with this
weekend rainfall.

On Monday, the shortwave and larger-scale, synoptic trough axis
will shift east of the forecast area, pushing a cold front
through. Much drier air will overspread the forecast area as high
pressure settles across a portion of the eastern CONUS. The
airmass associated with the high pressure will be noticeably
cooler starting on Sunday and continuing into early next week with
lows in the 40s and 50s, and highs in the 60s and 70s.

Martin

&&

.AVIATION...
(06Z TAFS)
Issued at 156 AM EDT Fri Apr 19 2024

VFR conditions continue with mid and upper level clouds blanketing
the area. However, shower activity is presently developing across N
AL, with some embedded in-cloud lightning starting to show up. This
activity is presently tracking almost due E. Have included a tempo
shower at RYY from 10-13Z with VCSH at other Atlanta metro terminals
except ATL. May need to expand tempo group into the remainder of the
metro area depending on progression of this activity. More tstm
activity is forecast to sag into N GA this afternoon. As indicated
by previous shifts, models are performing poorly, so confidence in
timing and areal extent of tstms is fairly low.

//ATL Confidence...06Z Update...
High for all elements over the next several hours, medium for timing
and S extent of early morning convection, low-medium for timing and
extent of afternoon thunderstorms.

SEC

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          63  83  55  65 /  30  30  30  80
Atlanta         62  79  56  62 /  30  30  40  80
Blairsville     55  73  48  57 /  30  20  40  80
Cartersville    58  76  50  60 /  30  20  30  80
Columbus        67  86  60  70 /  20  40  30  80
Gainesville     62  80  55  62 /  30  20  30  80
Macon           66  86  60  71 /  20  40  30  80
Rome            58  75  50  60 /  30  20  40  70
Peachtree City  62  81  54  64 /  30  30  40  80
Vidalia         69  89  65  79 /  20  40  30  70

&&

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

$$

SHORT TERM...NListemaa
LONG TERM....Martin
AVIATION...SEC