Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 051741 AAB

Area Forecast Discussion...Updated
National Weather Service Peachtree City GA
140 PM EDT Wed Aug 5 2020

...18Z Aviation Forecast Discussion...

.SHORT TERM /Today through Thursday/...

An upper longwave trough from the Great Lakes into the southeast
states will persist through the period. The forecast area will stay
in a moist southwesterly flow with a series of weak impulses moving
through. This should allow for a more typical summer pattern with
strong daytime heating and instability combining to support
scattered showers and thunderstorms. A few strong to isolated severe
storm are possible.

A fairly similar setup is expected for Thursday with the same
longwave trough and a weak boundary lingering across central GA.
This will again allow showers and thunderstorms in the afternoon and
evening. Otherwise, high temperatures for today and Thursday are
forecast to be just around seasonal normals with temperatures in the
upper 80s across northern Georgia and getting into the 90s elsewhere.


.LONG TERM /Thursday Night through Tuesday/...

The broad upper level trough will remain over the eastern CONUS as
the extended period begins. Meanwhile, a weak frontal boundary will
remain stalled across central Georgia, and will serve as a moisture
gradient with higher dewpoints and precipitable water values to the
south and relatively lower values to the north. Southerly flow will
nonetheless allow for continued moisture return across the area,
which will be sufficient for the development of scattered showers
and thunderstorms each afternoon. The surface boundary will also
provide a focus for relatively higher rain chances at the end of the
week and into the weekend.

Over the weekend, the upper-level low from which the trough extends
will move away to the northeast as an upper ridge builds in over the
eastern Great Plains and the midwestern CONUS. At this point, the
higher-amplitude upper level pattern will begin flattening out and
the upper level flow pattern will become nearly zonal by the end of
the weekend. This weak zonal upper level flow and stagnant
conditions at the surface will allow for warmer conditions to
develop over the weekend. The surface boundary is expected to
gradually retreat northward on Sunday into Monday, which will allow
for dewpoints in the mid 70s and precipitable water values in the
1.75" to 2" range to spread into north Georgia. With more available
moisture, PoPs should increase accordingly during the early parts of
next week, with high-end chance to low-end likely PoPs across the
area during peak heating hours.

Temperatures will be on the rise again on Friday, and will continue
to stay warm through the weekend and into next week. Temperatures
through the period will be mainly 3-7 degrees above climatological
normals for this time of the year, with highs in the low to mid 90s
and lows in the upper 60s to mid 70s. Saturday and Sunday are
currently anticipated to be the hottest days of the extended period.
It should also be noted that relatively cooler temperatures can be
expected in the higher elevations of northeast Georgia. These
temperatures combined with humid conditions will produce heat
indices in the 100-105 degree range primarily south of the I-20
corridor each afternoon.



18Z Update...

VFR conditions will predominate across the forecast area for the
majority of the forecast period outside of isolated to scattered
convection. Areas of localized MVFR or lower conditions are possible
between 06Z and 14Z, with KAHN, KMCN, KCSG most likely TAF sites to
see some brief impacts. Winds will be mostly south to west 4-8kt
this afternoon, becoming light southeast to east after 00Z then
transition back to south to west 4-8kt after 14Z tomorrow. Scattered
afternoon and evening convection should peak in coverage around 21-
23Z then diminish to isolated at most after 02Z.

//ATL Confidence...18Z Update...

Medium to high.



Athens          92  70  90  70 /  30  30  50  30
Atlanta         91  71  89  71 /  30  20  40  20
Blairsville     83  64  81  63 /  40  30  60  30
Cartersville    90  70  89  69 /  30  20  40  10
Columbus        96  73  95  72 /  30  20  30  10
Gainesville     88  69  87  69 /  30  30  50  30
Macon           95  72  94  72 /  30  30  40  20
Rome            91  69  89  69 /  30  20  30  10
Peachtree City  91  70  90  70 /  30  20  30  10
Vidalia         96  74  95  74 /  40  30  60  30




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