550
FXUS62 KFFC 151148
AFDFFC
Area Forecast Discussion
National Weather Service Peachtree City GA
748 AM EDT Sat Mar 15 2025
...New 12Z Aviation Discussion...
.SHORT TERM...
(Today through Sunday)
Issued at 329 AM EDT Sat Mar 15 2025
The short term portion of the forecast will be dominated by the
potential for severe weather later this afternoon/evening and into
the overnight hours.
In the mid levels, low pressure currently across central IA will
move almost directly north into central Canada today. A digging
longwave trough will move into the MS River Valley this evening and
continue eastward overnight. Strong shortwave energy will dig into
the base of the trough as it pushes east, with the trough becoming
negatively tilted as it approaches the CWA.
A cold front and squall line are currently approaching the
Mississippi River Valley. Supercell thunderstorms have developed
ahead of the main line across eastern Mississippi. The hi-res models
have initialized fairly well with the activity across eastern MS.
These storms should continue to track eastward across portions of AL
early this morning, but should weaken as move into eastern portions
of AL.
The squall line and cold front will continue to move east today and
begin impacting the CWA later this afternoon/evening and well into
the overnight hours. As is the case across MS this morning, expect
convection to break out ahead of the main squall line/front across
western portions of GA later this afternoon and evening.
This storm system will have plenty of energy at all levels to work
with. Especially impressive is the mid level dynamic energy and the
broad scale lift that is associated with the couple jet structure at
250mb. At the lower levels, a strong LLJ of 70 to 80kt at 850mb will
translate eastward today. Closer to the surface, the system will
have some SBCAPE to work with, generally 500-1000 J/kg. What is also
impressive are the mid level lapse rates that have consistently
ranged from the 6.6-8 C/km. The lapse rates are a bit higher during
the late afternoon/early evening (peak heating), so any storms that
develop out ahead of the main line will have a higher potential to
produce some large hail. There is also high potential for damaging
wind and tornadoes with strong shear and high helicity values that
start in the late afternoon/evening and will continue well into the
overnight hours. SPC has kept the "Moderate Risk" between the ATL
metro and the AL state line, this looks very reasonable. Models do
try and weaken the line as it pushes into east central portions of
GA. Do think some weakening is likely, but strong, dynamically
forced systems like these do tend to stay stronger than some of the
models forecast. Have kept the severe wording in the zones, but not
confident of the coverage as the system approaches the far SE zones
towards 12Z.
In addition to the potential for severe weather, this system will
also produce locally heavy rainfall. Training of storms combined
with orographic lift will lead to enhanced rainfall totals across
portions of north GA. Will go ahead and extend the FFA a little
eastward this morning.
Will also make some slight adjustments to the Wind Advisory. Will
also extend it eastward to cover the Athens metro. The gradient does
seem to lessen a bit across SE areas of the CWA.
NListemaa
