Scientific Forecaster Discussion
Area forecast discussion...updated for aviation
National Weather Service Peachtree City Georgia
735 PM EDT Tuesday Sep 16 2014
Short term /tonight through Wednesday night/...
cold front has finally started pushing into north Georgia at afd
time...pushed by the strengthening trough aloft and surface high
pressure building toward the Ohio Valley. Drier dewpoints are still
mainly back in Tennessee but they are at least heading this way. For
this afternoon...weak vorticity lobe pushing across especially southern
Georgia is helping to fire convection in the warm and unstable
airmass south of the front. Kept probability of precipitation lingering across portions of
central Georgia just past 06z tonight but for the most part expect
quiet conditions thereafter. Residents of north and central Georgia
will notice quite a marked decrease in temperatures tonight from last
night...current forecast is running on average 4-5 degrees cooler
with much drier dewpoints in place as well. May see some patchy
dense fog in the morning before winds start kicking up behind the
For Wednesday...again a few degrees cooler behind the front than
what we are seeing this afternoon at least across most of north
Georgia due to the weak cold air advection behind the front...though
some areas in central Georgia may actually be a degree or so warmer.
Probability of precipitation are limited to extreme southeast zones as the digging upper
trough aloft pushes the best moisture way south towards the Florida
Peninsula. Temperatures Wednesday night drop another few degrees
with dry air really dominating the area...with lows actually prognosticated
a couple of degrees below normal. Highs Thursday another degree or
so cooler than Wednesday with continued weak cold air advection. For
now have not included probability of precipitation Thursday afternoon but another area of
high pressure will dive down the confluent flow aloft into the Great
Lakes which may be enough to swing winds around to the east and
possibly enhance potential for orographic precipitation. Too far out
to really pin down any details at this point. Overall though...we
are looking at much nicer fall-like conditions building in behind
Long term /Thursday through Tuesday/...
overall extended forecast looks to be on track. Have made minor
adjustments to temperatures and dew points to account for latest
model trends. No other significant changes were made. Previous
discussion still applies and is included below...
/issued at 425 am EDT Tuesday Sep 16 2014/
the extended forecast starts out with the second front south of
the County Warning Area and a drier airmass moving into north an central Georgia.
Strong high pressure ridge builds in behind the second front which
will also help to suppress any precipitation through the weekend.
Both the GFS and European model (ecmwf) agree with the drier air mass moving
in...but they also agree that there will still be a bit of
moisture lingering over eastern and southern sections of the state
through day 7. The models are showing less moisture than the past
few runs o have decide to pull all precipitation out of the forecast Thursday
through Sat. A third front moves into north Georgia late Sunday so will
keep a slight chance of precipitation sun/Mon. Models also continue to
indicate cooler temperatures are in store for the state...especially with
the cooler drier air mass moving in. Looking T high temperatures in the
70s and 80s through the beginning of next week.
a cold front from Franklin through Peachtree City and Covington to
Athens will continue moving slowly southeast tonight. A few showers
will linger in central Georgia south of the front...but with such low
probability of precipitation around 20 percent...will leave out of csg and mcn tafs.
Otherwise...VFR conditions expected until early morning when MVFR
visibilities in fog may occur. VFR conditions prevail again on Wednesday
by 15z with a northwest flow of 5-10 kts.
//Atl confidence...00z update...
high on all elements.
Preliminary point temps/pops...
Athens 65 82 61 82 / 20 5 5 10
Atlanta 67 82 62 81 / 20 0 0 5
Blairsville 59 76 54 77 / 20 5 5 5
Cartersville 63 82 56 81 / 20 5 5 5
Columbus 69 88 65 86 / 20 5 0 5
Gainesville 65 80 61 79 / 20 5 5 5
Macon 67 88 61 85 / 30 5 5 5
Rome 63 81 56 82 / 10 5 5 5
Peachtree City 64 84 57 83 / 20 5 0 5
Vidalia 69 89 67 87 / 40 20 10 10