Scientific Forecaster Discussion
fxus62 kffc 201135
Area forecast discussion
National Weather Service Peachtree City Georgia
735 am EDT sun Aug 20 2017
Previous discussion... /issued 407 am EDT sun Aug 20 2017/
Short term /today through Monday/...
Ridging aloft stretching across the Gulf Coast states into Texas
strengthens through this evening as it shifts eastward. By Monday
morning, it begins to weaken as it shifts offshore into the
Atlantic. Short term models are in good general agreement showing
impulses along the SC/Georgia coast and back into the Florida Panhandle.
Surface high pressure centered over the Appalachians will shift
eastward through Monday as well. This will turn the surface winds
to the east and southeast through the period. Mainly scattered
afternoon clouds expected each afternoon, and expect good viewing
across north Georgia for the total solar eclipse.
This pattern will keep a relatively dry pattern across the area
today with increasing moisture on Monday. This moisture, especially
over central GA, will combine with impulses and daytime heating
allowing isolated to scattered thunderstorms to develop by Monday
afternoon, and continuing into the early evening. Southeast flow
against the foothills of the Appalachians will enhance orographic
lift and could see isolated showers/thunderstorms in far northeast GA
as well Monday afternoon. Anticipate any convection on Monday will
diminish rapidly with the loss of daytime heating.
Guidance temperatures in good agreement through the short term
period showing just above normal temperatures and will continue to
take a blend. Temperatures during the eclipse tomorrow look to stay
steady an hour before the maximum obscurity (between 1pm-2pm), then
drop a couple degrees up to 30 minutes after Max obscurity (3pm).
Temperatures are expected to rebound quickly after the eclipse. This
drop in temperature is not expected to impact the high temperatures
Long term /Monday night through Saturday/...
The upper ridge will dominate our forecast area into the middle of
the upcoming week with mainly diurnal showers and thunderstorms
across north and central Georgia. A strong trough moving across the
Great Lakes should push another front into north Georgia Wednesday
night into Thursday. Drying is indicated for north Georgia during that
time with the front continuing to push into central Georgia Friday and
Saturday. Low pops will remain for central GA since the final
position of the frontal boundary in uncertain. For weeks end GFS
and European model (ecmwf) Show Low pressure developing east of the SC coast. For
now the main effect for US would seem to be a dry easterly flow
into much of the forecast area...except maybe some moisture
lingering into the western counties.
VFR through the period. Few/sct diurnal cu during the afternoon.
Winds have shifted out of the east with speeds at 5kts or less.
Wind speeds will remain 6kts or less through the afternoon before
diminishing to 4kts or less after 01z.
//Atl confidence...12z update...
high confidence all elements.
Preliminary point temps/pops...
Athens 94 72 92 73 / 0 0 5 10
Atlanta 94 74 92 74 / 0 0 10 10
Blairsville 88 65 88 67 / 5 5 20 10
Cartersville 94 72 93 73 / 0 0 10 10
Columbus 97 75 94 76 / 0 0 20 20
Gainesville 93 72 91 73 / 0 0 5 10
Macon 95 74 92 74 / 0 5 20 20
Rome 95 71 94 73 / 0 0 5 10
Peachtree City 94 72 93 73 / 0 0 20 10
Vidalia 96 75 92 75 / 10 5 30 20