029
FXUS62 KFFC 030558
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
158 AM EDT Wed Jul 3 2024

...New 06Z Aviation Discussion...

.SHORT TERM...
(This afternoon through Wednesday)
Issued at 252 PM EDT Tue Jul 2 2024

Upper level high pressure remains centered over Mississippi/Alabama,
which is expected to continue expanding eastward into an E-W
oriented ridge over the short term period. An associated surface high
pressure is positioned near the New England coast. Surface ridging
associated with the high has developed along the lee side of the
Appalachians and has spread across much of north Georgia from the
northeast. The airmass under this wedge of high pressure is
noticeably milder and drier than observed the last several days. High
temperatures will range from the mid 80s to near 90 this afternoon.
Dewpoints have also dropped into the 50s to low 60s in the Atlanta
metro area and to the north and east. The frontal boundary that
traversed through the forecast area yesterday has become stationary
across south Georgia, with scattered showers and thunderstorms
ongoing in the vicinity of the front. Some of this precipitation will
continue across portions of south-central Georgia through the
afternoon, but a stable airmass within the wedge will keep PoPs to a
minimum across the northern 2/3 of the forecast area.

After a cloudy start the morning across the majority of the forecast
area on Wednesday, the wedge will begin to break down as the high
pressure center moves offshore into the Atlantic. At this time, the
frontal boundary will slowly lift back to the northeast, with
dewpoints in the upper 60s and 70s creeping back to the north in
kind. With increasing dewpoints and highs rising into the low 90s
across the majority of north and central Georgia (with the exception
of the higher elevations of the far northeast), MUCAPE values are
forecast to increase to 1000-1500 J/kg in portions of central and
west Georgia, south and west of the frontal boundary. These
instability values will be sufficient for scattered diurnally-driven
thunderstorms, with the highest coverage in south-central Georgia
where there will be the greatest low level moisture and precipitable
water values approaching 2 inches. With vertical profiles indicating
tall but thin CAPE profiles and very limited shear, the threat for
severe weather on Wednesday is shaping up to be quite low.

King

&&

.LONG TERM...
(Thursday morning through next Monday)
Issued at 252 PM EDT Tue Jul 2 2024

Key Messages:

 - A Heat Advisory may be needed (40% chance) for portions of east
   central Georgia between Friday and Sunday.

 - Afternoon and evening thunderstorms should become more numerous
   Friday, Saturday and Sunday.

Heat Concerns to End the Week:

The core of an upper level ridge will drift gradually eastward over
the course of this week. Overall, 500 mb heights should peak in
Georgia on Thursday or Friday, but 850 mb temperatures may continue
to inch upwards over the weekend. These trends should allow
temperatures to climb back towards the mid and upper 90s to conclude
the week. The warmer temperatures should be accompanied by surface
dewpoints in the 69-74 degree range, and this may push afternoon heat
indices back into the triple digits. Our current forecast suggests
heat indices above 105 in parts of Georgia Thursday, Friday, Saturday
and Sunday. If these values hold (a 1-2 degree decrease in surface
dewpoints or temperatures would prevent values over 105) then a Heat
Advisory (40% chance) may be warranted for some locations south and
east of Atlanta. Peak heat indices in the Atlanta Metro are currently
forecast to be in the 100 to 104 degree range.

Thunderstorms Chances Trending Upwards:

An upper level trough tracking through the Great Lakes should push a
weak frontal boundary towards Georgia late in the week. While the
strength of this boundary may be fading, it should still provide
sufficient lift to serve as a focal point for storm activity.
Guidance from the EPS and GEFS suggests increasing instability (Mean
SBCAPE values > 1000 j/kg) and moisture (PW values near 2 inches)
along and ahead of the frontal boundary. Combine these factors with
diurnal heating and the lift/surface convergence along the frontal
boundary, and an uptick in the coverage of afternoon and evening
thunderstorms is anticipated. Our forecast rain chances currently
peak near 60% on Saturday. The potential for strong or severe
thunderstorms remains low due to limited shear (surface to 500 mb
bulk shear generally less than 15 kt) and modest mid level lapse
rates (700-500 mb values near 5.5 C/km). If stronger storms do occur,
they would be most probable near the GA/TN border where bulk shear
values my be closer to 20 kt Friday and Saturday. Rainfall rates may
be local heavy with any storms that occur (1-2 inches per hour) due
to the potential for climatologically high PW values (in the 90th
percentile).

Albright

&&

.AVIATION...
(06Z TAFS)
Issued at 148 AM EDT Wed Jul 3 2024

Low cigs beginning to form near and S of the Atlanta metro area will
continue to expand and lower through the early morning hours. Cig
heights around the Atlanta are expected to range from 1800-2500 feet
(but lower cigs are possible around daybreak). Lower cigs are
expected for CSG and MCN. Ceilings are expected to lift and
eventually thin during mid to late morning. Light, mostly easterly
winds will become SE through the day. Wind directions may flirt with
S-SSW late in the afternoon or early in the evening at ATL, but
directions should average SSE. A few showers are possible at ATL in
the late afternoon or early evening. Scattered thunderstorms are
possible farther S at MCN and CSG.

//ATL Confidence...06Z Update...
Medium for morning cigs, high for other elements.

SEC

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          73  95  75  95 /  10  30  10  50
Atlanta         75  94  77  95 /  20  40  20  70
Blairsville     68  89  70  89 /  10  60  20  80
Cartersville    74  95  75  95 /  10  40  20  80
Columbus        75  94  76  96 /  30  50  10  60
Gainesville     74  94  76  93 /  10  40  10  60
Macon           73  95  75  96 /  30  30  10  50
Rome            75  96  76  95 /  10  50  20  80
Peachtree City  73  94  74  95 /  20  40  10  60
Vidalia         75  94  75  96 /  30  30  10  40

&&

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

$$

SHORT TERM...King
LONG TERM....Albright
AVIATION...SEC