Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 291140

Area Forecast Discussion
National Weather Service Peachtree City GA
640 AM EST Sun Nov 29 2020

...Updated for 12Z Aviation Discussion...

.PREV DISCUSSION... /Issued 428 AM EST Sun Nov 29 2020/

SHORT TERM /Today through Monday Night/...
Pretty busy short term forecast period due to a deepening surface
low near the LA/TX border heading northeast today towards the local
forecast area. The main forecast concerns through the period are the
potential for heavy rainfall and severe storms this evening and
overnight, strong winds across the area on Monday, and the potential
for snow across far northern Georgia late Monday night.

For today, chances for showers and thunderstorms are expected to
increase by late morning across southwestern portions of the area.
Precip is then expected to overspread the rest of the forecast area
through the day as a warm front lifts north ahead of the passage of
the low pressure system. Forecast QPF totals through early Monday
are slightly lower than previous forecast cycles but are around 1
inch with up to 2 inches generally north of I-20, aside from
potential for locally higher amounts across portions of northeastern
Georgia. The heaviest of the precipitation is expected to fall
Sunday evening through daybreak on Monday. This lines up well with
WPCs Marginal Risk of excessive rainfall across portions of far
northern Georgia where some isolated instances of flooding may be

The center of the low is forecast to cross northwestern Georgia
overnight tonight, pushing a cold front through the area before
daybreak. In addition to the threat for heavy rain, there is still a
threat for a few severe storms, generally from about 10 PM this
evening through 6 AM Monday morning. SPC has included portions of
far central Georgia in a Marginal Risk for severe storms and the far
southeastern tip of the CWA in a Slight Risk for severe storms. The
main threats will be gusty winds with the potential for a tornado as
well. Instability looks to be somewhat of a limiting factor with
<500 J/kg of MLCAPE forecast, although shear looks a bit more
favorable. The better instability will be across far central
Georgia, but the situation will continue to be monitored as there`s
still some uncertainty.

Surface winds are expected to increase significantly across the area
on Monday as the pressure gradient tightens with the passage of the
low. Winds are currently just slightly below wind advisory criteria,
but will need to be monitored with subsequent forecast updates as an
increase in winds could warrant issuance of an advisory. The passage
of this low pressure system is also expected to bring the coldest
airmass of the season so far. As cold air filters in faster than the
moisture can escape portions of northern Georgia, snow may mix in
with the rain late on Monday and overnight before transitioning to
snow. Current forecast calls for accumulations of up to an inch
across portions of northeastern Georgia, but especially in the
higher elevations, where totals up to 2 inches could be possible.
Low temperatures overnight into Tuesday morning are forecast to drop
to the lower 20s across the NE GA mountains with upper 20s across
the metro and low 30s elsewhere, around 5 to 10 degrees below


LONG TERM /Tuesday through Saturday/...
The extended portion of the forecast begins will a cold airmass
moving into N GA with low temps Tuesday morning in the 20s and
30s. This cold airmass does not allow temps to get out of the 40s
for high temps Tues and lows Wed morning will dip down into the
20s for almost the entire state. These chilly mid- week
conditions warm slightly by the end of the week ahead of the next
weather system. Deepening, strong low pressure system moves over
the Southern Plains by late Friday, with the flow around the large
system increasing pops over GA beginning Thu afternoon/evening.
The models have come in better agreement with timing and position
of the low as it moves eastward through the Tennessee Valley
Friday and into the Mid-Atlantic states Saturday. At this time,
models agree with a decent-sized dry slot following the initial
precip on Friday, keeping significant rainfall amounts from
accumulating over Georgia. Moisture associated with the low`s
center and wrap- around could provide another shot of winter
precip for north Georgia Saturday.



12Z Update...
Mainly LIFR cigs across the area this morning with LIFR vsbys to
match. Vsbys should improve to VFR and cigs should improve to at
least IFR this afternoon. SHRA looks to impact taf sites at CSG
closer to 16/17Z and metro taf sites & MCN after 18Z. Cigs should
lower again to IFR/LIFR with precip. TSRA possible at MCN/CSG/ATL
with squall line moving through 5-8Z Monday, but can`t be ruled
out at other metro taf sites. Winds currently calm to light E
winds and should remain on the east side through the day at
5-10kts. Winds shift NW and increase by daybreak Monday with
gusts to 25kts possible at ATL/metro taf sites..

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



Athens          61  49  52  30 /  80 100  30   5
Atlanta         60  45  48  29 /  90 100  30  10
Blairsville     56  41  43  24 /  70 100  50  30
Cartersville    61  43  47  27 /  80 100  30  10
Columbus        64  48  51  30 /  90 100  20   5
Gainesville     58  46  49  29 /  80 100  40  10
Macon           65  51  54  30 /  80 100  30   5
Rome            63  44  46  28 /  80 100  30  10
Peachtree City  62  45  48  27 /  90 100  20   5
Vidalia         67  59  62  33 /  60  80  30   5




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