Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
704 am EDT Monday Aug 31 2015
Previous discussion... /issued 329 am EDT Monday Aug 31 2015/
Short term /today through Tuesday/...
A much drier forecast looks to be in store from a rain standpoint
this short term period.
The upper low pressure system is now moving away and has taken the
deep moisture and dynamics with it. An upper ridge builds some
over the area from the Atlantic. Still plenty of low level moisture
in place but overall instability looks to be lacking. Can not rule
out a pop up shower or thunderstorm today into early evening.
Not much change for Tuesday except for a surface trough over the
far east and southeast counties with some added moisture and instability.
This could allow for slightly higher chances of mainly afternoon
showers and storms.
Forecast high temperatures running 3-4 degrees below normal today and
close to normal for Tuesday. Forecast low temperatures running close
to normal tonight.
Overall confidence is medium to high.
Long term /Tuesday night through Sunday/...
Long term portion begins with a relatively benign pattern in
place...a Stark contrast from where we could have been had Erika
become a major player. Instead...590dm upper high dominates the
local area with a good deal of middle level dry air in place to keep
probability of precipitation at or below climatology. The exception will be the extreme southeast
corner of the forecast area where northern fringes of residual
Erika moisture looks to provide a jolt to pop chances with low end
likely planned for Wednesday afternoon.
Pretty much the same pattern through Friday is expected although
middle and upper level ridge does break down a bit. But no
significant upper level systems of note to impact the region and
with only modest deep layer moisture values...will hold probability of precipitation in
the low end chance range. Blend is giving ME some maximum temperatures that
seem a little low even with the easterly flow and plan to tweak
those up just a touch.
High pressure building over the NE states looks to bring a wedge
scenario to the region for the weekend and this pattern really
will hold temperatures in check while increasing rain chances. Using
moisture fields for probability of precipitation...could actually see some likely coverage
for this pattern but this far out will limit to high end chance
for the eastern sections.
IFR-MVFR ceilings in place. Some MVFR visibilities due to fog and
some drizzle. Conditions expected to improve from 15z on to scattered-
broken 3500-4500 feet in the afternoon. Surface winds east-northeast less than 10
kts becoming variable for some locations this afternoon.
Confidence for thunderstorms today is too low to include in the
//Atl confidence...12z update...
low to medium confidence for visibilities to start.
High confidence for ceilings and winds to start.
Medium confidence for ceiling improvement and wind direction
during the day.
Preliminary point temps/pops...
Athens 84 69 89 70 / 20 10 20 20
Atlanta 83 71 89 72 / 20 10 20 20
Blairsville 80 63 83 64 / 30 20 40 10
Cartersville 84 67 89 69 / 20 10 20 10
Columbus 86 72 90 74 / 20 10 20 20
Gainesville 82 69 87 71 / 20 10 20 10
Macon 86 70 89 72 / 20 10 20 20
Rome 84 67 89 69 / 20 10 20 10
Peachtree City 83 68 88 70 / 20 10 20 20
Vidalia 88 72 90 73 / 20 10 50 30