Scientific Forecaster Discussion
fxus62 kffc 201859
Area forecast discussion
National Weather Service Peachtree City Georgia
259 PM EDT sun Oct 20 2019
Short term /tonight through Monday night/...
skies will continue to clear as the moisture remnants of Post-
tropical storm Nestor erode away throughout the afternoon.
Overnight, patchy fog will be expected thanks to the widespread 1-2
inches of rainfall increasing the relative humidity across the
forecast area. Lows should fall into the mid-50s and stabilize there
as temps meet the local dewpoints. As the morning fog lifts, thicker
low-level cloud cover will be possible through tomorrow morning
replaced in the afternoon by mid- and upper-level clouds ahead of
our next synoptic system.
By tomorrow afternoon, an upper-level negatively-tilted longwave
trough will be moving into the Midwest with a Stout associated cold
front moving across the Mississippi River into the Ohio/Tennessee
River valleys tomorrow night. With southwesterly mid-level flow
ahead of the frontal system, a large amount of moisture flux with
saturate the atmosphere, with precipitable waters between 1.5-2.0 inches expected,
giving way to prefrontal storms ahead of a cold front with drier air
behind it. Showers and weak thunderstorms will begin to move into northwest
Georgia late tomorrow afternoon and move through the rest of the forecast
area overnight. With very limited instability, we're not currently
expecting a severe threat despite high values of bulk shear with
Long term /Tuesday through Sunday/...
two frontal boundaries expected to impact the County Warning Area in the long term
portion of the forecast.
The first cold front is expected to exit the area Tuesday but we
will still see some morning and early afternoon showers and
thunderstorms mainly across southern and eastern portions of the
state. Models are still showing some indications that strong
thunderstorms are possible, with some potential for an isolated
severe thunderstorm. Upper jet structure and good mid level
dynamics will be present. Since the front is coming through much
of the County Warning Area Monday night, surface instability will be minimal but
thunderstorms will still be possible during the day tues. Temps
will cool down behind the cold front for Tuesday night through
Wednesday night, but will quickly moderate during the end of the
The second cold front is expected by the end of the work week and
into the weekend. Models are very divergent in the mid levels for
the end of the week but they are all showing something as we get
into days 6 and 7. There are huge differences in timing and
intensity between the models so for now going with a 20-30
percent chance of showers and isolated thunderstorms.
IFR ceilings are eroding quickly across the forecast area back to VFR
conditions. Sfc winds are northwest and will stay on the west side, at
less than 10 kts through the day today. Overnight winds will be
light and shift from the SW to the southeast between 06-09z and stay out
of the south-southeast tomorrow. Tomorrow morning cigs are expected to drop
across the northern taf sites with IFR conditions forecast between
12-17z. MVFR/IFR vsbys could also be a concern overnight for ahn
//Atl confidence...18z update...
low to medium on overnight cigs and vsbys.
High on all other elements.
Preliminary point temps/pops...
Athens 55 77 62 73 / 5 20 80 40
Atlanta 56 76 60 69 / 5 30 80 20
Blairsville 51 69 53 64 / 5 40 100 30
Cartersville 55 78 56 70 / 5 50 90 20
Columbus 58 81 63 74 / 5 30 80 30
Gainesville 55 74 60 70 / 5 30 90 30
Macon 56 81 64 76 / 5 10 70 50
Rome 56 79 56 70 / 0 60 90 20
Peachtree City 55 78 59 71 / 5 30 80 20
Vidalia 59 84 69 81 / 0 10 50 50