013
FXUS62 KFFC 062343
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
743 PM EDT Sat Jul 6 2024



...New 00Z Aviation Discussion...

.SHORT TERM...
(This afternoon through Sunday)
Issued at 229 PM EDT Sat Jul 6 2024

Key Messages:

 - Scattered afternoon and evening thunderstorms may produce
efficient rainfall rates and isolated wind gusts near 40 mph today
and Sunday.

 -  Hot and humid conditions will continue in the region through
Sunday.

This Evening and Tonight:

A weak stationary frontal boundary was positioned near the
Interstate 20 corridor this afternoon. Thunderstorms were ongoing
along and south this boundary, and they should continue (with a
gradual southward drift) into this evening. Poor mid level lapse
rates (5.5 C/km or less) and a lack of shear (generally less than 15
kt) suggest that severe weather is unlikely today. The strongest
storms may however generate hefty rainfall rates (1-3 inches per
hour), frequent lighting and isolated wind gusts near 40 mph. Our
12Z sounding indicated a PW values of 2.13 inches, well above the
90th percentile for early July.

Heat remains a concern this afternoon and the Heat Advisory is in
place for portions of central and northern Georgia through 8 PM.
Widespread heat index values in the 102-107 degree range have been
observed, and isolated spots may approach 109 degree before either
storms arrive or diurnal heating ends.

Today`s rainfall and the high dewpoints could lead to patchy fog
development early Sunday morning. For the fog to have a chance to
form the region will need to see good clearing and radiational
cooling tonight. The degree to which this will occur is iffy, though
we have included some patchy fog in our official forecast for Sunday
morning.

For Sunday:

The primary decision point for Sunday was whether or not a Heat
Advisory will be needed for portions of central Georgia. Surface
dewpoints should remain high (mid to upper 70s) in the region and
this will keep ambient conditions unpleasantly muggy. It will also
significantly prop up heat indices. However, afternoon high
temperatures look like they may be 1-3 degrees cooler compared to
Saturday`s highs. Cloud cover, afternoon showers and thunderstorms,
and a slight decline in 850 mb temperatures should be the main
factors behind these temperatures declines. Given these
considerations peak heat index values should peak in the 100-106
degree range Sunday afternoon. While this may have patches of the
area flirting with the 105 degree threshold for a Heat Advisory for
a couple of hours, it doesn`t appear sufficient to warrant an area
wide advisory. Thus we are forgoing the issuance of a Heat Advisory
for Sunday at this time. This decision will be reevaluated this
evening and early Sunday morning. There is a 40% chance that a Heat
Advisory will be issued for a portion of central Georgia by a later
shift.

As mentioned above, thunderstorms will be a concern Sunday afternoon
and evening. The front draped across the region today should washout
somewhat on Sunday. This will limit low level support for
thunderstorms and favor diurnally driven convection that is less
predictable in terms of location. It should also allow better
precipitation chances to spread back into northern Georgia (a trend
evident in the 12Z HREF guidance). Small mid level temperature
declines may allow 700-500 mb lapse rates to creep towards 6.0 C/km
Sunday afternoon (slight improvement but still poor for severe
weather). Effective shear for storms to work with should be similar
to today (generally 20 kt or less). Given these considerations
severe weather is unlikely Sunday. PW values near 2.0 inches will
remain in the region and this should favor efficient rainfall rates
(1-2.5 inches per hour) and precipitation loading (for downburst
winds). Thus with the strongest storms we can`t rule out isolated
gusts near 40 mph and localized rain totals of 2 inches.

Albright

&&

.LONG TERM...
(Monday morning through next Friday)
Issued at 229 PM EDT Sat Jul 6 2024

Typical summertime conditions will persist through the long term
forecast. Hot daily temperatures in the upper 80s to mid 90s
accompanied by triple digit heat index values and afternoon storm
chances are expected through the end of the period. As high pressure
over the forecast area wanes through the early half of the work
week, a broad trough over the eastern half of the CONUS will help
keep moisture in place over the forecast area and disturbances
within the flow will produce daily thunderstorm chances during the
afternoon and evening hours. These storms are likely to be the
typical summertime pulse variety with frequent lightning and gusty
winds being the primary hazard. Despite abundant surface instability
peaking during the afternoon hours, shear is lacking and ultimately
reducing any appreciable risk of widespread severe weather. Another
hazard in any strong storms through the week will be periods of
heavy rainfall as PWATs are forecast to range from 2.0-2.5"
through much of the long term. While QPF through Saturday morning
ranges generally from 2.0-3.0+", locally higher amounts will be
possible in strong thunderstorms. As Beryl moves inland well to
our west, there remains considerable uncertainty over the
trajectory that Beryl`s remnants will ultimately take as it gets
absorbed by the trough. It appears that enhanced moisture is
likely for us midweek, but will continue to monitor the evolution
of this forecast in future cycles. Monday will be the most active
day for showers and thunderstorms with numerous to widespread
showers and thunderstorms. This will help moderate temps in the
upper 80s to low 90s, but temperatures rebound quickly and will
continue warming through the end of the period to the mid 90s.
Heat index values are currently forecast to reach the triple
digits for many locations through the week but appear to remain
sub Heat Advisory criteria, thanks to the increased cloud cover
and rain chances.

KAB

&&

.AVIATION...
(00Z TAFS)
Issued at 729 PM EDT Sat Jul 6 2024

Even with lingering SHRA/TSRA over middle Georgia diminishing
after 02Z, VFR conditions expected through 09Z at which point IFR
stratus is expected to develop persisting through 14Z. Another
round of sct SHRA/TSRA expected Sunday after 19Z with enough
coverage to warrant TEMPO at all sites. Sfc winds light and
variable after sunset then light E after 10Z then SE 4-7kts after
15Z.

//ATL Confidence...00Z Update...

Medium confidence on IFR stratus likelihood and timing.
High confidence on all other elements.

SNELSON

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          72  90  73  89 /  30  50  40  80
Atlanta         74  91  74  91 /  40  50  30  70
Blairsville     67  87  69  85 /  20  50  40  80
Cartersville    70  94  73  93 /  40  40  30  70
Columbus        75  94  76  93 /  60  70  40  80
Gainesville     72  90  74  88 /  30  50  40  70
Macon           74  91  74  91 /  70  70  40  80
Rome            72  95  74  95 /  20  30  30  70
Peachtree City  72  92  73  91 /  40  60  30  70
Vidalia         75  92  75  91 /  60  70  40  80

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for GAZ027-036>039-
047>051-056>062-066>076-078>086-089>098-102>113.

&&

$$

SHORT TERM...SNELSON
LONG TERM....KAB
AVIATION...SNELSON