Scientific Forecaster Discussion
fxus62 kffc 140050 aab
Area forecast discussion...updated
National Weather Service Peachtree City Georgia
750 PM EST Fri Dec 13 2019
Made a few minor adjustments to the weather grids, lightning pushing
a little farther north than previously depicted in the grids. The
remainder of the forecast elements remain well on track this evening
and minimal changes made otherwise.
Previous discussion... /issued 640 PM EST Fri Dec 13 2019/
.00z aviation forecast discussion...
Short term /tonight through Saturday night/...
broad upper trough over the southeast will continue into late
Saturday...with flow becoming more zonal by the end of the period. A
series of short waves will rotate through the trough during this
time. The first wave...which brought rain to our area
overnight...was moving into the Carolinas. Rain will continue to
redevelop this afternoon and into the overnight as the next wave
approaches. Expect The Wedge to hold until the surface front enters
western Georgia toward sunrise Saturday...with pops diminishing from the
west late tonight. Low pops will continue in the far north through
Saturday afternoon as the last wave moves through the Tennessee Valley.
With easterly winds and rain...temperatures may be close to
afternoon Max values with little cooling expected through the
evening. So overnight lows should be non diurnal over much of the
area. At this time no Flood Watch is planned.
Long term /Sunday through Friday/...
only tweaks to the long term based on the latest guidance.
the start of the long-term forecast period will bring a dry respite
on Sunday with surface high pressure over the southeast and zonal
flow aloft ahead of the next trough pushing into the southern
rockies. Temperatures Sunday will range from the 50s north to the
mid 60s in central Georgia.
On Monday, the next system will take shape as the upper trough
swings into the plains and a surface low develops in the arklatex
region. Showers will increase across north Georgia as early as
Monday afternoon, and temperatures Monday will warm 10-15 degrees
above normal in advance of the cold front. The surface low will lift
northeastward into the Ohio Valley Monday evening into Monday
night, dragging the cold front eastward into the forecast area by
Tuesday morning. Pops will thus be on the increase during this
time across north Georgia and transition southeastward through the
day Tuesday as the cold front pushes across the area.
Currently, the higher risk for strong/severe thunderstorms looks to
be to our west where better alignment of instability and shear will
be present. While shear will remain favorable, surface instability
will be quickly waning as the front enters the forecast area Monday
night. The risk for any strong thunderstorms will continue to be
monitored as we approach this time frame. At this time, included
slight chance thunder across the western half of the area Monday
night into Tuesday morning. Healthy rainfall totals continue to be
expected from Monday into Tuesday, specifically in far north Georgia
where widespread 1-1.5" and isolated amounts up to 2" are currently
The front will clear the area Tuesday night into Wednesday morning
bringing dry weather and much cooler temperatures. After highs
5-10 degrees below normal on Wednesday, widespread freezing
temperatures appear likely by Thursday morning.
IFR or lower conditions are expected to predominate across the
forecast area through the overnight period. Will see conditions
transitioning to IFR to MVFR between 10z and 14z most areas and VFR
by 18-22z most areas. Widespread drizzle and fog through the
overnight period as well with scattered to numerous showers.
Isolated thunderstorms are possible across central Georgia, however
these should remain south of the Atlanta Metro area taf sites and
kahn. Northeast to east winds 4-10kt become north to northwest after
06z and increase to 9-14kt W/ gusts 17-20kt by 18z.
//Atl confidence...00z update...
Confidence is medium to high on all elements.
Preliminary point temps/pops...
Athens 41 55 39 61 / 80 20 5 0
Atlanta 42 54 39 60 / 80 20 5 0
Blairsville 41 48 34 54 / 80 40 20 5
Cartersville 43 54 38 60 / 80 20 10 5
Columbus 44 58 41 66 / 80 10 5 0
Gainesville 42 52 38 58 / 80 20 10 5
Macon 44 59 38 64 / 80 20 5 0
Rome 43 54 38 59 / 80 30 10 5
Peachtree City 44 56 38 62 / 80 20 5 0
Vidalia 44 60 41 66 / 80 30 5 0