Scientific Forecaster Discussion
fxus62 kffc 070922
Area forecast discussion
National Weather Service Peachtree City Georgia
422 am EST Sat Dec 7 2019
Short term /today through Sunday/...
A lingering secondary weak upper impulse is allowing for some
isolated light rain/drizzle potential mainly in portions of central
Georgia early this morning, otherwise should transition to northwest flow aloft
and dry Saturday on tap. Some continued mid level moisture
especially in central Georgia could keep some cloud coverage hanging
around today. Should be a fairly pleasant start to the weekend with
afternoon highs mostly in the low to mid 60s.
Sfc high center sliding into New England this evening will result in
a cad wedge building in for Sunday across the area. We can expect a
shift to cooler temps (about 10 degrees lower than Saturday across
north ga), increased easterly gradient winds, and some low level
moisture overrunning/isentropic upglide causing increased cloud
coverage and some return of afternoon shower potential in parts of
the south and west. Ascent and late shower potential could also be
aided by a weak upper shortwave.
Long term /Sunday night through Friday/...
The long term period begins on Sunday night with a wedge still in
place across northeast Georgia. As southwest flow advects moisture
over The Wedge, chances for showers will continue into the early
hours on Monday. Have included slight chance pops for Sunday
afternoon with increasing chances Sunday night into Monday
afternoon, as The Wedge breaks down. A large longwave trough will
push a strong cold front towards the area on Tuesday into Wednesday
with the arrival of the front during the day on Wednesday. Have
included chance pops across much of the area with likely pops across
portions of northern Georgia in addition to the mountains. The
highest quantitative precipitation forecast amounts for Monday through Wednesday look to be across
far northern Georgia, around 1 to 2 inches with around a half inch
or less further south. In addition, models are showing some slight
differences on the backside of this system with the GFS showing
another shortwave trough developing and crossing the local forecast
area late Wednesday into Thursday and the ECMWF, while still showing
the shortwave trough, clears precip from the local forecast area by
Thursday and takes the trough much further south of the area.
Overall, decided to trend on the drier side for pops in this time
period, with slight chance to chance pops Wednesday afternoon and
clearing across the area on Thursday.
Post frontal passage, high pressure will build into the area at the
surface, providing dry weather for Thursday. By Friday, chances for
precipitation will increase again as models show a developing
surface low in the Gulf moving towards the local forecast area on
Friday and Saturday. Although models are showing some differences in
timing, have included chance pops for Friday through the early
High temperatures on Monday and Tuesday will be about 5 to 15
degrees above average in the 60s and 70s, returning to the 40s and
50s through the rest of the extended. Overnight lows Tuesday morning
will be very warm in the 50s and 60s, around 20 to 25 degrees above
average. Otherwise, lows through the rest of the extended are
expected to be in the 30s and 40s.
some MVFR cigs near 2-3 kft are near katl and the southern sites
this morning. Isolated -ra is possible with a weak impulse mainly
near kmcn also this morning and cannot be ruled out near katl but
chance too low to include for now. NE winds 3-6 kts are expected
thru most of period with increasing 8-10 kts out of east by 06z
//Atl confidence...06z update...
medium on MVFR cig improvement timing this morning.
High on all else.
Preliminary point temps/pops...
Athens 62 40 53 46 / 0 5 10 50
Atlanta 62 43 53 48 / 5 5 20 50
Blairsville 58 36 49 42 / 5 5 10 60
Cartersville 63 43 54 47 / 5 5 10 50
Columbus 64 48 60 53 / 10 5 20 40
Gainesville 60 40 50 45 / 0 5 10 60
Macon 64 42 58 50 / 10 5 20 30
Rome 63 43 55 47 / 5 5 10 50
Peachtree City 63 43 56 48 / 5 5 20 40
Vidalia 67 43 62 52 / 5 5 10 20