076
FXUS62 KFFC 040608
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
208 AM EDT Thu Jul 4 2024

...New 06Z Aviation Discussion...

.SHORT TERM...
(This evening through Thursday)
Issued at 312 PM EDT Wed Jul 3 2024

An upper level ridge continues to extend from the north-central Gulf
of Mexico northeastward along the Atlantic coast. As associated
surface high pressure moves away to the northeast, the wedge pattern
over north Georgia continues to weaken. As temperatures warm and
lingering cloud cover begins to scatter out, showers and
thunderstorms have begun to develop roughly south of I-20. PoPs this
afternoon are forecast to be highest across west- central Georgia,
where dewpoints are in the mid 70s and low-level moisture is most
ample. A gradual warming trend is also ongoing under the influence of
the aforementioned ridge. Aside from highs in the 80s in the higher
elevations of far northeast Georgia, highs are forecast to be in the
low to mid 90s this afternoon. MUCAPE values through the remainder of
the afternoon are forecast to range from 1000-1500 J/kg roughly
south of I-20. These instability values will be sufficient for
continued convection. With vertical profiles indicating tall but thin
CAPE profiles and very limited shear, the threat for severe weather
this afternoon are expected to remain below severe limits. With slow
storm motion and precipitable water values between 1.6-2 inches, a
few storms may produce locally heavy rain. Precipitation chances will
diminish after sunset.

For the 4th of July, low temperatures are forecast to start the
morning mainly in the mid 70s. Overnight and into the morning,
continued southerly flow will bring in more Gulf moisture, and low
level moisture and dewpoints in the mid 70s will continue to spread
northward. Furthermore, the warming trend will continue, with
temperatures rising into the mid to upper 90s across much of the
area. The combination of hot temperatures and abundant moisture will
allow for heat index values to reach critical thresholds of 105
degrees in many locations. A Heat Advisory remains in effect for the
forecast across north and central Georgia from 1 PM until 7 PM
tomorrow, with the exception of far northeast Georgia where heat
indices will be well outside of criteria. Diurnally-driven
thunderstorms are expected once again on Thursday afternoon. Highest
PoPs are forecast across the southwest portion of the forecast area
and the lowest PoPs are forecast in the far eastern portion of the
area where a strong cap could potentially inhibit widespread
convective development. While an organized threat for severe
thunderstorms is not expected, a few storms could become strong and
produce locally heavy rain and frequent lightning. Considering high
precipitable water values, water loading in downdrafts of stronger
storms could also produce gusty winds.

King

&&

.LONG TERM...
(Friday morning through next Tuesday)
Issued at 312 PM EDT Wed Jul 3 2024

Key Messages:

 - Hot and humid conditions will keep portions of northern and
   central Georgia Georgia on the cusp of Heat Advisory thresholds
   through the weekend.

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

An Outlook for the Weekend:

Hot and humid conditions will remain the primary weather concern
this weekend. Weak upper level ridging stretching from the Gulf coast
to the Carolinas and rising 850 mb temperatures (to ~21 C) should
contribute to gradual increases in ambient surface temperatures (mid
and upper 90s). However the real kicker for the heat should be rising
surface dewpoints driven by moisture advection ahead of a weak cold
front. Widespread dewpoints in the lower 70s are anticipated in the
state on Friday. Over the weekend dewpoints should become more
bifurcated (spit by the front) with upper 60s and lower 70s in
northwest Georgia and mid 70s in east central Georgia. The elevated
surface dewpoints should produce oppressive humidity and push heat
indices into the triple digits south of the front. Widespread heat
index values of 102 to 108 degrees are anticipated on Friday. Then on
Saturday and Sunday the highest values (105 to 110 degrees) should
become more focused over central and eastern Georgia. A Heat Advisory
may be needed for portions of northern or central Georgia on Friday
(30% chance). Then over the weekend a Heat Advisory is likely (60%
chance) for portions of central Georgia. The forecast position of the
frontal boundary (near Interstate 85) suggest a low probability
(20%) of a Heat Advisory for the Atlanta Metro over the weekend. An
important caveat to keep in mind for the heat forecast is that in
lingering cloud cover from convection could hold temperatures down
and reduce the need for any Heat Advisories.

The second portion of the forecast to monitor over the weekend will
be the rising thunderstorms chances. Severe thunderstorms are
unlikely due to limited shear and modest 700-500 mb lapse rates (~5.5
C/km) along and ahead of the front. That said, surface hinder the
temperature forecast convergence along the front and decreasing mid
level subsidence should support more widespread diurnally driven
thunderstorm activity Friday, Saturday and Sunday. More isolated
activity may occur during the overnight hours each day. Elevated PW
values, near or above 2 inches (90th percentile for early July),
should support rain rates of 1 to 3 inches per hour with the
strongest convection. This could produce some isolated flooding
concerns, especially Saturday afternoon and evening.

Considerations of Early Next Week:

Guidance from the EPS and GEFS suggests a broad area of troughing
from the Great Lakes to the Central Plains early next week. With weak
ridging favored over the Western Atlantic, this should lead to weak
flow aloft and minimal subsidence over Georgia. Though the higher PW
airmass that moved in over the weekend may moderate some on Monday,
moisture and humidity should generally linger in the region. The
combination of these two factors should allow scattered afternoon and
evening thunderstorm activity to linger in the region early next
week. Temperatures in the region should remain relatively unchanged,
with widespread highs in the low to mid 90s continuing to push heat
index values into the 98 to 105 degree range.

Albright

&&

.AVIATION...
(06Z TAFS)
Issued at 155 AM EDT Thu Jul 4 2024

VFR conditions are expected at the northern TAF sites overnight.
MVFR/IFR cigs and MVFR vsbys are possible at MCN and CSG around
daybreak. Winds will be light and variable to calm overnight. Winds
will be mostly light SSW today. All sites except AHN have PROB30
thunderstorms for this afternoon. Coverage around the Atlanta metro
area is a bit uncertain, so will continue to evaluated prior to the
12Z package.

//ATL Confidence...06Z Update...
Medium confidence on thunderstorm chances this afternoon, high on
other elements.

SEC

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          75  96  75  95 /  10  50  30  60
Atlanta         77  94  75  92 /  20  60  40  60
Blairsville     71  88  70  87 /  30  80  60  50
Cartersville    74  94  72  92 /  30  80  50  50
Columbus        77  95  76  94 /  40  60  40  80
Gainesville     76  94  75  92 /  10  60  50  50
Macon           75  95  75  94 /  20  50  20  70
Rome            76  95  75  93 /  20  80  50  40
Peachtree City  74  94  73  93 /  20  60  40  60
Vidalia         74  96  76  95 /  20  40  20  70

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM this afternoon to 7 PM EDT this evening
for GAZ001>005-011-012-019>021-024-025-027-030>039-041>062-
066>076-078>086-089>098-102>113.

$$

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