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000
FXUS62 KFFC 181827
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
227 PM EDT Sun Apr 18 2021



.PREV DISCUSSION... /Issued 736 AM EDT Sun Apr 18 2021/

UPDATE...

Updated for the 12Z Aviation Discussion.

PREV DISCUSSION... /Issued 445 AM EDT Sun Apr 18 2021/

SHORT TERM /Today through Monday/...

As the short term period begins, a weak disturbance in the upper
level flow is moving eastward across central Georgia. A surface
low associated with this system is similarly moving northeastward
across the Gulf Coast and towards the Atlantic Coast. The heaviest
and most widespread showers are south and east of the forecast
area as the short term period begins, but some isolated to
scattered showers remain possible in the far southern tier through
the remainder of the morning hours today. No instability is
present across the area, so thunderstorms are not expected this
morning. Any additional precipitation that occurs this morning is
expected to stay south of a line from Columbus to Macon.

Deeper moisture will be pushed to the south and east of our area
as drier air and 850 mb cold air advection spread into north
Georgia today. Low temperatures will start the morning in the 40s
in north Georgia and in the 50s in central Georgia. Meanwhile, an
upper level shortwave currently over the Great Lakes region will
quickly drop southeastward into the Mississippi Valley this
afternoon and towards Georgia later in the day. Precipitation
chances are expected to be minimal with this system with only
limited low level moisture over the forecast area. High
temperatures this afternoon will run near to just below
climatological normals across the area, primarily in the 70s.

As the shortwave swings through Georgia on Monday, it will help
push moisture further south and east away from the forecast area.
A dry and seasonal day is expected on Monday as high pressure
builds into the area. With highs in the 70s once again and
dewpoints dropping into the upper 30s and low 40s during the
afternoon, minimum relative humidity values will range from 25-30
percent. While outside of critical fire danger thresholds, the
potential for lower RH values will need to be monitored in ensuing
forecast updates.

King

LONG TERM /Monday Night through Saturday/...

The degree of moisture return across central Georgia on Tuesday
remains in question as low-level flow becomes southwesterly and a
500-mb vort max traverses the area. The NAM is more optimistic
than the GFS, as it advects 1.2-1.4 inches of PWAT across the
southern third of the CWA, while the GFS limits PWATs to around 1
inch over our far southeastern counties. Models are continuing to
produce meager instability at best, so just maintaining a slight
chance for thunder across the far southeastern portion of the CWA
on Tuesday.

On Wednesday, a larger-scale upper-level trough will swing across
the Great Lakes region, driving a cold front across the CWA and
leading to breezy/gusty conditions. CAA in the wake of the front
will be evident on Thursday morning, given lows in the mid-30s to
lower 40s across much of the area, and lows right at freezing
across the higher terrain of northeast Georgia. Wanted to draw
attention to the possible issuance of a Frost or Freeze product
for Thursday morning, as the Frost/Freeze program started on April
15th for the northeastern CWA.

The upper-level pattern will transition to ridging for Thursday
and Friday with high pressure building in across the area. This
setup will favor increased fire danger concerns, as relative
humidities are forecast to drop below 25% for several hours in the
afternoon on both days. It looks like our next system to bring
rain will arrive on Saturday, though models are at odds concerning
where across the Southeast the moisture axis will lie.

Martin


&&

.AVIATION...
18Z Update...
Some mid to high level clouds across the area this afternoon will
clear out for Monday. No precip or restrictions to VSBYs expected.
Winds will stay out of the NW at 10kt or less today and tonight.
Will see wind speeds increase into the 10-14kt range Monday
afternoon.

//ATL Confidence...18Z Update...
Confidence high on all elements.

01

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          74  49  75  50 /   0   5   0   5
Atlanta         73  51  73  52 /   0   5   0   5
Blairsville     68  42  67  43 /   5  10   0   0
Cartersville    72  46  72  47 /   5   5   0   5
Columbus        77  51  76  53 /   5   5   0   5
Gainesville     72  49  72  50 /   0   5   0   5
Macon           77  51  77  50 /   5   5   0   5
Rome            72  47  73  47 /   5   5   0   5
Peachtree City  74  48  74  49 /   0   5   0   5
Vidalia         79  57  78  56 /  30   5   5   5

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...King
LONG TERM....Martin
AVIATION...01