385
FXUS62 KFFC 151738
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
138 PM EDT Thu Aug 15 2024



...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Friday)
Issued at 437 AM EDT Thu Aug 15 2024

The sfc high and associated lagging upper level ridge continues to
break and move eastward. Following trough will help to bring
moisture back into the area through Friday, however PWATs will have
to climb from <1.5". Instability will stay below 500 J/Kg and likely
closer to 0. PoPs will remain near zero for the entire timeframe
except for the tale end of the short term period. An approaching
cold front will introduce increasing PoPs to the area on Friday
afternoon, starting in northwest GA and moving southeast. Ensembles
keep most likely CAPE well below 2000 J/Kg, however that doesn`t
completely rule out the potential for some gusty winds along
anything that does form. For now the main wind threat will be in our
far northwestern counties. PWATs of near 2" may also mean some
locally efficient rainmakers.

Temperatures will remain seasonable to just below climatological
norms due to dry air and continued dry wedging. Highs will remain in
the low to mid 90s for the area with dewpoints in the mid 60s to
near 70.

SM

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 437 AM EDT Thu Aug 15 2024

Things look a bit more active for the start of the long term.
Relatively deep trough for August will be digging into the eastern
CONUS as it is squeezed between Hurricane Ernesto downstream and a
building subtropical ridge upstream. Broad surface low will set up
across the Great Lakes region. Tongue of moisture will draw up into
it, with the best quality return just to the west of the area by
Friday night. This return will have to squeeze around the drier air
to the east brought in by the broad circulation from Hurricane
Ernesto. A little bit of this return should begin to edge its way
into Georgia late in the evening to overnight. Ongoing convection to
the north may be able to push through in the form of a linear
segment, or outflow from previous convective clusters may provide
for more sloppy, disorganized convection across NW GA. Bulk shear
from 0-6 km is broadly 20-30 kts (be careful of convectively
contaminated soundings) with CAPE values of 1000-2000 J/kg, so some
severe winds will be possible, especially if storms are a bit more
organized as depicted in a few of the convective allowing models
that go out this far. Marginal Risk (Level 1 of 5) is in effect
Friday evening into overnight for a 5% chance of seeing severe winds
within 25 miles of a location.

Saturday, upper level low slowly continues to slowly grind to the
east. Better moisture return should overrun the entire CWA as both
the hurricane passes by to the east moving quickly northward and the
cold front finally begins to push down towards the CWA. More
widespread thunderstorm activity is expected. SBCAPE values in the
longer term guidance are once again 1000-2000 J/kg with some broad
20+ kt bulk shear values pushing in during the evening. Marginal
Risk (Level 1 of 5) is in effect Saturday as well for a 5% chance of
seeing severe weather within 25 miles of a location. Will need to
monitor this day to see if convective guidance favors any kind of
linear systems given the setup, which could see severe chances
increase a bit.

Cold front looks like it will move through Saturday night into
Sunday. Broad afternoon thunderstorm chances are in place that
somewhat represent the uncertainty of just where the front may be
and how quickly it will be moving through. Wouldn`t be surprised if
another categorical risk is introduced on this day for severe
weather, especially down in central Georgia, as the parameter space
looks similar to the previous 2 days in many ways.

Once the front moves through, drier air filters in and our rain
chances look to go away for a bit. This pattern may be in place for
quite some time if the ensemble averages are to be believed, with
both GEFS and EPS favoring a large subtropical ridge continuing to
build to the west. Rain chances are basically zero in this drier
airmass. The other thing is the temps - overnight lows are wonderful
for August, in the 60s (and even some 50s in the mountains!) across
much of north and central Georgia.

Lusk

&&

.AVIATION...
(18Z TAFS)
Issued at 129 PM EDT Thu Aug 15 2024

VFR conditions expected at area taf sites this cycle.
Expect typical summer cu field to develop and maintain in the 035
to 045 level both today and Friday. Cannot rule out a low cloud
deck 008 to 010 in the early AM hours friday similar to this
morning. For now..kept a SCT deck in for early AM but will need to
monitor overnight.
Also a wind shift to the SW expected overnight as a front
approaches. Put a 10z line in at ATL for the wind shift but could
be plus or minus an hour.

//ATL Confidence...18Z Update...
High confidence all elements

30

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          69  92  71  94 /   0  10  10  30
Atlanta         71  93  73  93 /   0  10  20  50
Blairsville     64  86  67  87 /   0  30  40  60
Cartersville    71  94  72  93 /   0  20  30  60
Columbus        72  95  73  96 /   0  10   0  40
Gainesville     69  91  72  93 /   0  10  20  40
Macon           68  92  69  94 /   0   0   0  30
Rome            70  93  73  93 /   0  30  40  60
Peachtree City  69  93  71  93 /   0  10  10  40
Vidalia         69  91  70  93 /   0   0   0  10

&&

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

$$

SHORT TERM...30
LONG TERM....Vaughn
AVIATION...30