378 
FXUS62 KFFC 011127 AAA
AFDFFC

Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
727 AM EDT Sat Apr 1 2023



...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Sunday)
Issued at 428 AM EDT Sat Apr 1 2023

As of 0830z (4:30 AM) this morning, a NE-to-SW oriented line of 
convection with embedded supercells is nearing the NW corner of 
the state. The line is progged to push through Metro Atlanta and 
Athens between 11z-15z, and push through Macon and Columbus 
between 13z-18z.

As far as the SPC Convective Outlook valid until 12z, far NW GA 
remains under a Slight Risk with the remainder of N GA roughly 
along and north of I-85 under a Marginal Risk. SPC/RAP 
mesoanalysis depicts MLCAPE peaking around 500 J/kg across this 
area as the line of convection moves through, along with both 
effective SRH and 0-1 km SRH around 200-300 m^2/s^2 and favorably 
curved hodographs. All this said, expect for convection to 
maintain intensity across the Slight and Marginal Risk areas 
through the morning and continue to pose a threat for damaging 
wind gusts and tornadoes. Speaking specifically to the tornado 
risk, a Tornado Watch is in effect across NW GA until 13z.

After 12z, the SPC Convective Outlook picks up with a Marginal 
Risk generally along and south of I-20 and a Slight Risk roughly 
from a Columbus to Macon to Augusta line. Assuming adequate 
daytime heating and resulting destabilization, could see SBCAPE 
and MUCAPE climb to 1000-1500 J/kg across the Slight Risk area 
this afternoon. The environment is forecast to remain supportive 
of robust updrafts -- with the potential for supercells -- given 
hi-res models depicting sufficiently high supercell composite 
parameter values (which take into account MUCAPE, effective SRH, 
and effective bulk wind difference). In addition to damaging winds
and tornadoes, severe storms this afternoon could also produce 
hail, though marginal mid-level lapse rates could prove to be a 
limiting factor.

Cloud cover will clear quickly behind the line of convection as 
the attendant cold front pushes through. A Wind Advisory is in 
effect from 12z this morning to 03z Sunday (11 PM tonight) for 
counties along and north of I-20. Sustained winds will be 20-25 
mph and gusts will be 35-40 mph as the pressure gradient tightens 
in the wake of the departing low pressure system that is driving 
the severe weather threat. Wind gusts could be even higher at 
elevations above 2000 feet.

Much colder air will arrive overnight with Sunday morning lows in
the mid-30s to to mid-50s. Sunday will be sunny to mostly sunny 
with afternoon highs in the upper 60s to mid-70s. 

Martin


&&

.LONG TERM...
(Sunday night through Friday)
Issued at 428 AM EDT Sat Apr 1 2023

A cold front will bring additional chances for showers and 
thunderstorms for the late week into the weekend.

High pressure will be in place across the CWA for the first part 
of next week. A cold front will begin to move out of the central 
US into the Mississippi River Valley by late Tuesday into 
Wednesday. The boundary should cross the Mississippi River on 
Wednesday and then move through much of the CWA on Thursday. The 
front will end up stalling across southern GA or the FL panhandle 
for the latter half of the week into the early part of the weekend
as it becomes parallel to the flow in the mid levels. Models have
been pushing the boundary further south from run to run and not 
confident that the boundary will push as far south as the northern
GOMEX. So, precip chances for the end of the week into the early 
weekend will depend heavily on where the boundary sets up. Several
waves of low pressure are progged to move east along the 
boundary, so the potential for locally heavy rainfall will exist 
along and south of where the front stalls. 

Models are also still progging the chance for some showers and 
thunderstorms overnight Sunday into Monday as a strong southern 
stream shortwave moves across the Gulf States. Thickness values do
indicate that there is some potential for an organized area of 
thunderstorms and will not make any major changes to this period 
in the forecast.

NListemaa


&&

.AVIATION...
(12Z TAFS)
Issued at 710 AM EDT Sat Apr 1 2023

TSRA have begun to impact RYY and PDK, with ATL and FTY expected 
to get TSRA starting at 12z and AHN at 13z. This messy area of 
convection will clear the ATL area sites and AHN by 15z-16z with 
quickly improving ceilings in its wake. The convection will impact
MCN and CSG between 15z-17z. SW winds are breezy ahead of the 
convection -- 15-20 kts with gusts of 25-30 kts. Winds will remain
just as gusty after the convection moves through, although wind 
direction will become westerly.

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

Martin


&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          44  72  50  70 /   0   0  10  30 
Atlanta         45  71  52  70 /   0   0  20  40 
Blairsville     36  68  44  65 /   0   0  10  30 
Cartersville    41  70  50  70 /   0   0  20  40 
Columbus        48  75  54  75 /   0   0  20  50 
Gainesville     43  71  50  67 /   0   0  10  30 
Macon           49  74  53  75 /   0   0  10  40 
Rome            41  71  50  70 /   0   0  20  40 
Peachtree City  43  72  51  73 /   0   0  20  50 
Vidalia         52  76  54  78 /   0   0   0  20 

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 11 PM EDT this evening for GAZ001>009-
011>016-019>025-027-030>039-041>055-057.

&&

$$

SHORT TERM...Martin
LONG TERM....NListemaa
AVIATION...Martin