Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 221750
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
150 PM EDT Fri Mar 22 2024


...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Saturday)
Issued at 338 AM EDT Fri Mar 22 2024

Key Messages:

- Widespread rainfall is expected today into tonight
  with accumulations of 1-2 inches.

- Severe weather is not expected today or tomorrow (Saturday).

- The risk for flash flooding with this rainfall event is low.

Mid-level water vapor satellite imagery reveals a shortwave
trough currently over northeastern TX with several areas of precip
occurring downstream across parts of the Southeast. Light to
moderate rain will spread across the CWA from south to north this
morning into the afternoon as vort maxes associated with the
trough pass over and encourage lift and moisture advection. At the
surface, a weak wedge will develop this morning as a 1030+ mb
high pressure system settles over the Northeast. Rain falling into
the weak wedge should strengthen it as the day goes on, in turn
keeping much of north GA in a stable airmass. Have included a
slight chance of thunderstorms mainly along and south of I-20 this
afternoon into early tonight given non-zero CAPE depicted in the
hi-res guidance, but expect that any thunderstorms will be
elevated and not strong or severe as ample cloud cover even
outside of the wedge will hinder instability. Speaking of the
wedge, the temperature forecast today is rather tricky... Have
gone with the lower end of guidance to reflect the influence of
the wedge and ample cloud cover. Much of north GA may not see
temperatures exceed 60 degrees today, with low- to mid-60s across
central GA. Overnight lows will generally be in the 50s. Breezy
conditions are expected today with east winds 10-18 mph and gusts
20-28 mph. Even breezier conditions are expected along the
mountain ridgelines.

Widespread rain is expected through the afternoon into tonight as
the shortwave continues its trek eastward over the Southeast.
Rainfall accumulations are forecasted to range from 1" to 2".
Given limited instability and poor mid-level lapse rates, do not
expect efficient enough rainfall rates to cause flooding issues.
That said, nearly the entire CWA is under a Marginal Risk for
flash flooding per the WPC, which is probably prudent given
increased near-surface soil moisture from recent rainfall. A
slight chance for elevated thunderstorms will exist overnight,
mainly across central GA. The shortwave trough will shift eastward
over GA tomorrow with showers gradually ending from northwest to
southeast through the afternoon and evening. Portions of east-
central GA could have isolated thunderstorms if cloud cover clears
enough during the diurnal maximum to allow for destabilization.
Winds -- while becoming northwesterly in the wake of the exiting
shortwave -- will remain breezy at 10-18 mph and gusts 20-28 mph.
Again, gustier conditions can be expected along the mountain
ridgelines. High temperatures are forecasted to be in the lower
60s to lower 70s -- warmer than today as cloud cover scatters out.

Martin

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 338 AM EDT Fri Mar 22 2024

Saturday night, a few isolated showers could be lingering across
our far southeastern counties but should otherwise be tapering off
as the upper level trough axis and surface cold front slide
eastward. Overnight Saturday into early Sunday morning,
temperatures will bottom out in the upper 30s and 40s across the
forecast area as the cool continental airmass behind the front
overspreads north and central Georgia. Sunday, daytime
temperatures are expected to rebound quickly under sunny skies
into the 60s as ridging aloft builds in from the west. Upper level
ridging and surface high pressure remains over the forecast area
through the early part of the week with seasonable spring-like
temperatures expected (daytime highs in the 60s to low 70s and
lows in the 40s to 50s). A brief, but pronounced wedge transpires
as high pressure establishes itself east of the Appalachians, high
temperatures across far the northeast Georgia Piedmont are likely
to be running a bit cooler (NBM members have as much as a 7 to 8
degree spread in high temperatures across the region). Have opted
for a blend of NBM/NBM10 across far northeast Georgia to account
for the wedge. Additionally, with the drier post-frontal airmass
in place at the surface, a stout dry layer ~900mb diagnosed in
ensemble model soundings could see a few locations achieve or get
close to critical minimum relative humidly thresholds for fire
weather.

The next weather maker for the forecast area will come as a broad
500mb trough over the Plains progresses eastward. A strong
surface low will develop across the central/northern Plains
bringing a cold front producing showers and the potential for a
few rumbles of thunder to the forecast area starting early Tuesday
morning. As the front makes its push towards the area during the
afternoon hours, a plume of surface based CAPE progged in model
guidance will be in place over western and central Georgia
coinciding with strong bulk shear (>50kt). Despite inability being
on the meager side, could see isolated thunderstorms with this
system, primarily over western Georgia and areas south of I-20.
Models diverge in solutions beyond Tuesday with uncertainty over
the speed and strength of the progressive shortwave to the west.
For now, have maintained chance PoPs through late Wednesday night
through early Thursday. QPF from Tuesday morning through Thursday
range from 0.75 to 1.5".

KAL

&&

.AVIATION...
(18Z TAFS)
Issued at 142 PM EDT Fri Mar 22 2024

The prevailing mix of VFR, MVFR and IFR (ceilings 500-7000 ft AGL
and visibility of 2 to P6SM) conditions should transition to a
mix IFR/LIFR (ceilings 300 to 800 ft AGL and visibility of 1 to 5
SM) conditions after 00Z Saturday. Rain will accompany the lower
ceilings and visibility, and should be widespread through 12Z
Saturday, then it will be more scattered from 12Z to 20Z Saturday.
Easterly winds (6 to 15 kt, with gusts to 25 kt) will linger
through 03Z. A couple isolated thunderstorms can`t be ruled our
from KMCN southward between 22Z Friday and 20Z Saturday. Then
winds will transition to a northern direction by 15Z Saturday.


//ATL Confidence...18Z Update...
Overall confidence in the KATL TAF is moderate.
High confidence in the wind forecast.
Moderate confidence in the precipitation and ceiling forecast.
Low confidence in the visibility forecast.

Albright

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          54  67  37  66 / 100  40   0   0
Atlanta         55  66  38  66 /  90  40   0   0
Blairsville     49  60  30  66 /  90  50   0   0
Cartersville    52  64  33  68 /  90  50   0   0
Columbus        58  69  41  69 /  90  30   0   0
Gainesville     53  67  37  65 / 100  50   0   0
Macon           58  69  42  68 / 100  40   0   0
Rome            53  65  34  69 /  90  50   0   0
Peachtree City  54  67  36  67 / 100  40   0   0
Vidalia         61  72  46  66 / 100  50  10   0

&&

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

$$

SHORT TERM...Martin
LONG TERM....KAL
AVIATION...Albright


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