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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KFFC 021143
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
643 AM EST Tue Mar 2 2021


.UPDATE...

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Updated for the 12Z Aviation Discussion.
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&&

.PREV DISCUSSION... 
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/Issued 416 AM EST Tue Mar 2 2021/

..Tuesday Morning Forecast Discussion...

SHORT TERM /Today through Wednesday/...

With the cold front that pushed through the forecast area yesterday
continuing to move southward into the northern Gulf of Mexico, a
cooler airmass is in place across much of the region. Temperatures
will be cooler this morning relative to the unseasonably warm past
few days, with lows ranging from the upper 30s in far north Georgia
to the upper 40s in south-central Georgia. More moisture is present
across the southern portion of our area, with scattered light
showers ongoing in portions of central Georgia. Another transition
in the pattern is then expected today as an upper level shortwave
over the ArkLaTex region moves into the Lower Mississippi Valley.
Meanwhile, a surface low associated with this shortwave will develop
over the northwestern Gulf. As this system approaches our area, deep
moisture will advect into north and central Georgia. Furthermore, as
the surface low moves northeastward out of the Gulf, a broad area of
isentropic lift in advance of the system will promote widespread
rain showers.

These showers will progressively spread northeastward through the
forecast area throughout the day, with PoPs becoming categorical
across central Georgia by this afternoon and the entire CWA by
tonight. Instability values ahead of this system appear to be
marginal but not entirely negligible -- enough to warrant a mention
of a slight chance of thunderstorms along with the widespread
showers in central and east Georgia during the late afternoon and
evening. Model guidance continues to support the axis of heaviest
rain falling over south-central Georgia this evening through
Wednesday morning. Rainfall totals associated with this system will
range from 2 to 2.5 inches along and south of a line roughly from
Cusseta to Macon to Wren. Locally higher rainfall totals up to 3
inches will be possible. Rainfall totals will progressively decrease
north of this line. Taking a look at antecedent conditions in the
area of the heaviest forecast rainfall in central Georgia, soils are
fairly dry and most river stations across the area are measuring
normal streamflows. As a result, only isolated instances of flash
flooding should be the extend of any hydrological issues.

Widespread rain and overcast skies will keep high temperatures today
mostly in the low 50s across north and central Georgia during the
day today. Temperatures on Wednesday morning will lower into mainly
the upper 30s to low 40s, with the exception of some mid 30s in the
higher elevations of northeast Georgia. There is the possibility of
a light rain/snow mix in the highest elevations of far northeast
Georgia during the early morning hours on Wednesday before sunrise,
but no accumulation of any wintry precipitation is expected. The
axis of the upper level shortwave will clear the area on Wednesday
morning, with precipitation coming to an end from west to east
during the morning and early afternoon. Northwesterly flow and
approaching high pressure behind the system will set up a cool and
dry conditions on Wednesday and into the beginning of the extended
period.

King

LONG TERM /Wednesday Night through Monday/...

The long term period will be relatively quiet in the wake of the
upcoming deluge for central/southern Georgia. Synoptically, a high-
amplitude ridge will set up over the western CONUS, with a stout
longwave trough axis through the east coast and western Atlantic
placing the forecast area in a northwest flow pattern. The
anticyclonic vorticity advection between these two systems will fuel
subsidence in central Canada, forming a high pressure system that is
progged to spill out into the eastern CONUS through the long term,
helping to keep most of the long term period quiet and temperatures
pretty seasonal.

The only wrench in the machine is a mid-level cutoff low that will
drift across the Four Corners region, underneath the broader upper-
level ridge, on Thursday. This system will progress eastward towards
Georgia, but model guidance shows it will mostly be deflected to the
south with a surface low pressure forming in the Gulf. Nevertheless,
moisture overrunning a frontal zone, will flow into the forecast
area on Friday night through Saturday morning. The result of this
overrunning moisture is still unclear with long-term guidance going
back and forth on the extent of the precip from this system. For
now, we`ll settling on roughly a 40 percent chance for rain showers,
primarily on Saturday morning, with a chance for some
non-accumulating rain/snow mix in the higher elevations.

Thiem
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&&


.AVIATION...
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12Z Update...
Conditions are primarily VFR across north and central Georgia as
the period begins, with mostly upper level clouds. 6-10 kt winds
are currently shifting from NW to NE and will continue to shift
towards E by 15-16Z. Widespread rain showers will build
northeastward across the area throughout the day, arriving at
CSG/MCN by 16-17Z and the ATL metro sites by 21-22Z. Showers will
persist through the overnight hours and early Wednesday morning.
MVFR ceilings will develop as the rain arrives today, and then
lower to IFR during the overnight hours, mainly after 03Z.

//ATL Confidence...12Z Update...
High confidence on all elements.

King
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&&


.PRELIMINARY POINT TEMPS/POPS...
Athens          54  39  62  38 /  60  90  60   0
Atlanta         51  40  60  40 /  80  90  50   0
Blairsville     51  36  59  35 /  30  80  40   0
Cartersville    54  39  61  37 /  70  90  40   0
Columbus        52  42  63  41 /  90 100  40   0
Gainesville     52  39  62  39 /  50  90  50   0
Macon           53  41  62  38 /  90 100  60   0
Rome            55  39  63  36 /  60  80  40   0
Peachtree City  52  40  62  39 /  90  90  50   0
Vidalia         53  44  59  41 /  90 100  70   0

&&

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

$$

SHORT TERM...King
LONG TERM....Thiem
AVIATION...King