783
FXUS62 KFFC 161745 AAA
AFDFFC

Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
145 PM EDT Thu May 16 2024



...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Friday)
Issued at 347 AM EDT Thu May 16 2024

Key Messages:

 - Dry and warm weather are expected in the region today.

 - Clouds and rain showers should return to the region Friday,
   leading to cooler temperatures across northern Georgia.

Today:

A transient upper level ridge building over Georgia today will
produce dry weather and warmer temperatures. Subsidence and drier
air below 700 mb should also result in mostly clear skies and
lower humidity. Afternoon highs in the mid to upper 80s are
expected for everyone except those who dwell in the mountains of
northern Georgia. If you happen to be one of those fine fellows
then you can anticipate an afternoon high temperature in the 70s.
Winds will be from the northwest again today, but weaker surface
pressure gradients will bring wind speeds (5 to 10 mph) down
compared to yesterday afternoon.

Tonight and Friday:

A weak surface high will settle over the southern Appalachians
tonight. This high will combine with diurnal decoupling of the
boundary layer to produce calm winds tonight. Widespread high
cloud cover should stream back into Georgia tonight as
southwesterly flow and moisture advection in the mid and upper
levels intensifies ahead of a developing trough in the Southern
Plains. A shortwave riding through the prevailing southwesterly
flow aloft could push a few rain showers into western Georgia
before sunrise on Friday. In general though the arrival of any
rainfall should hold off until the daylight hours on Friday for
most of Georgia. Expect rain chances to steadily increase through
the day. By Friday afternoon our forecast rain chances range from
80 percent in northwest Georgia to 30 percent in east Central
Georgia. Limited instability (MUCAPE < 500 J/kg in the 00Z HREF
guidance) suggests rain showers as the predominate precipitation
type, with any thunderstorm activity being isolated at best.
Widespread cloud cover and areas of rainfall should keep
temperatures suppressed Friday afternoon. High temperatures should
be 3 to 6 degrees below seasonal average in north Georgia (70s).
Highs in the 80s remain in the forecast from Macon southward where
more sunshine and less rainfall are expected.

Albright


&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 347 AM EDT Thu May 16 2024

The beginning of the long term is filled with uncertainty thanks
in part to unknowns around convective evolution on the previous
day. The HRRR, for instance, shows a significant ongoing MCS into
Friday night to the south of the CWA and into the Gulf. Depending
on how long this feature persisted, it would likely cut off more
significant moisture return to the CWA on Saturday, limiting the
overall rainfall. However, if this scenario doesn`t play out, such
as in much of the ensemble guidance and deterministic medium
range models, rain and convection focused along and rising north
of a baroclinic boundary would be on tap for Saturday, with the
possibility of some flooding/flash flooding. Like previous days,
QPF forecasts are 1-2" during the Saturday morning/afternoon time
period, but there remains high variability within this, with
details not likely to be fully known until we see how some of the
convective evolution plays out on the previous days.

The upper level wave responsible for this system continues to
move to the east and southeast by Sunday. Models are again
favoring development of surface low off the coastline that allows
for moisture to remain in the area on Sunday and then builds in
some potential sudo-wedging into Monday. PoPs have been bumped up
a touch, but for temperatures, there is a large potential range of
forecast temps on Sunday and Monday based on cloud cover and the
development of the sudo-wedge. The NBM IQR for AHN is 8 degrees on
Monday, with nearly 15 degree difference in the 90th and 10th
percentiles. So, have chosen to bring temps down compared to
previous forecasts, but didn`t want to completely buy in on the
wedge forming just yet. If models continue to bite on wedge
formation, expect forecast highs to drop further on those days.

We get another break from the precip from Monday into Tuesday as
we get caught between upper level low off the coast and system
developing across the Great Plains. Models show that rainfall
chances should increase into Wednesday, though timing and details
are still overall fuzzy.

Lusk


&&

.AVIATION...
(18Z TAFS)
Issued at 127 PM EDT Thu May 16 2024

Expect the Cu field to produce FEW/SCT 030-050 cloud bases
through the afternoon. Gradually lowering CIGs will move in from
the W overnight thru tomorrow (Friday) morning. Current thinking
is that all sites except for AHN and MCN will see MVFR CIGs by
late morning as -SHRA move in, and that MVFR will persist thru
much of the day. Have introduced a PROB30 from 18z-00z tomorrow
for -TSRA at ATL, but confidence is relatively low given the
anticipated OVC mid-level cloud deck hampering destabilization.
Winds will be WNW to NNW this afternoon and will become LGT to
calm overnight. Tomorrow, winds will generally be SSE, but could
occasionally teeter over to SSW.

//ATL Confidence...18Z Update...
Medium to high confidence on all elements.

Martin


&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          62  77  64  78 /   0  70  80  80
Atlanta         65  77  67  79 /  10  80  80  80
Blairsville     57  72  60  74 /  10  80  80  80
Cartersville    62  76  64  80 /  10  80  80  80
Columbus        67  82  69  80 /  20  70  70  80
Gainesville     63  74  65  77 /   0  80  80  80
Macon           65  83  68  80 /   0  70  70  80
Rome            62  77  65  80 /  20  80  80  80
Peachtree City  63  78  66  79 /  10  80  80  80
Vidalia         67  87  72  86 /   0  30  60  80

&&

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

$$

SHORT TERM...Albright
LONG TERM....Lusk
AVIATION...Martin