Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
640 am EST Monday Dec 22 2014
Previous discussion... /issued 422 am EST Monday Dec 22 2014/
Short term /today through Tuesday/...
The high pressure wedge has made its way into the state and is
expected to stick around until the next frontal system sweeps it
out. -Rain and drizzle across the area this morning with low clouds
and east winds. Best rain chances will remain across central Georgia
today as rain ban has set up SW to NE across southern Georgia. Probability of precipitation are
somewhat low today as first wave of Gulf moisture exits...but
deepening wave over the plains will bring another round of more
significant precipitation tonight and Tuesday. The Wedge is expected top
begin to erode today as warm front over south Georgia moves slowly
northward. High temperatures today will be mainly in the lower 50s but some
area in our extreme southern portion of the area will temperatures rise to
near 60 as The Wedge weakens. Guidance is still keeping SBCAPE
values pretty much 0...with MUCAPE values increasing across central
Georgia tonight into the 200 to 300 j/kg range. This instability
pushes into the the atl area Tuesday. Have decided to continue with
the mention of thunder in the forecast. By Tuesday afternoon/evening
a developing frontal system over the plains will move into the MS
River Valley and into Georgia Tuesday night. Have continued with
categorical probability of precipitation with showers and thunderstorms expected.
Long term /Tuesday night through Sunday/...
Closed low embedded in upper trough is expected to push into the
lower MS valley Tuesday night into Wednesday. Models still in good
agreement that surface front should be in the northwest corner of
the state around 12z Wednesday and exiting the forecast area by 00z
Thursday. A period of showers and possible severe thunderstorms is
still anticipated for Tuesday night into Wednesday. Quantitative precipitation forecast amounts
may approach the 2 to 3 inches mainly across central zones. No
Hydro issues anticipated yet but will continue to watch. Some
wrap around moisture still looks on track to cause a mix of rain
and light snow for the higher elevations late Wednesday night.
Thursday and Friday still look dry. GFS/European model (ecmwf) continue to have
differences in evolution of next system. European model (ecmwf) wants to bring a
strong short wave across the Tennessee/Ohio valleys during the weekend
while the GFS is not quite as strong and also a bit faster. With
the uncertainty involved...have continued chance or slight chance
probability of precipitation Friday night into Sunday.
wedge is still firmly entrenched over the state with low clouds
east winds and light rain or drizzle everywhere. At IFR to LIFR
ceilings through this taf period as The Wedge is hear to stay
through at least Tuesday morning. Winds will stay out of the east
with speeds in the 6-12kt range. Visibilities mainly IFR right now but
they should get into the MVFR range later this morning.
//Atl confidence...12z update...
medium to high.
Preliminary point temps/pops...
Athens 48 43 47 45 / 50 60 100 100
Atlanta 51 45 51 50 / 30 50 100 100
Blairsville 49 42 47 44 / 40 50 100 100
Cartersville 52 45 49 49 / 30 40 100 100
Columbus 56 52 64 60 / 30 50 100 100
Gainesville 48 42 45 45 / 40 60 100 100
Macon 53 49 62 60 / 50 50 100 100
Rome 53 46 53 51 / 20 40 100 100
Peachtree City 52 46 55 53 / 30 50 100 100
Vidalia 55 52 70 63 / 70 50 100 100