Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
350 am EDT Wednesday Aug 24 2016
Short term /today through Thursday/...
a rather strong surface high remains parked over the mid-Atlantic
coast with its ridge down the eastern Appalachians and across the
forecast area. This ridge remains across the area through Thursday
but weakens some. An upper ridge over the southern states centered
about southern MS is forecast to drift over the Tennessee Valley and southern
Appalachians through Thursday.
The main concern today is a weak short wave moving along in the
southern edge of the westerlies and brings in some deeper moisture and
lift. Models rather consistent developing scattered showers and
thunderstorms over N Georgia later this morning in an area of enhanced
instability. Precip potential will favor N Georgia and much of the western
border of the forecast area. With slightly drier air and instability
lacking over areas E and S...little or no convection is expected.
Any showers and storms over the area starting tonight are expected to
diminish quickly with the evening.
With the upper ridge established over the Tennessee Valley and southern
Appalachians for Thursday...the only place where there is potential
for afternoon showers and storms is the mountains of N Georgia where some
instability and the influence of the terrain will enhance convective
Forecast high temperatures are running near normal today and slightly
above normal for Thursday. Low temperatures are running near normal
Overall confidence is medium to high.
Long term /Thursday night through Tuesday/...
Long range models show good agreement through Friday with strong
mid and upper ridge of high pressure dominating across the
southeast and holding rain chances to only a slight to low chance
across mainly parts of north Georgia as a weak surface trough
sags into the Tennessee Valley. Over the weekend... both European model (ecmwf) and GFS
shift the 500mb ridge eastward to the mid Atlantic coast which
allows the associated surface ridge to build along the New
England coast. This overall synoptic pattern results in a deep
layer easterly flow across the state that appears to persist over
the weekend and into early next week. The forecast and overall
concern gets real interesting by late this weekend and into early
next week as the European model (ecmwf) is taking a surface low across South
Florida on Sunday... across the central Gulf Monday-Tuesday and
then inland along the Texas/la border early on Wednesday of next
week. In contrast... the GFS is taking this surface low up along
eastern Florida Monday-Tuesday... then along the Georgia coast on Wednesday
and finally turning the low pressure system northeast and out to
sea by end week. Now the overall synoptic pattern and deep
easterly flow would favor a westward movement of any low pressure
system moving toward Florida or into the southeast-eastern Gulf... and
therefore the latest European model (ecmwf) solution seems to be a bit more
reasonable at this time. Either way... both long range models
are showing a low pressure system pushing up into Florida by late
weekend or early next week... so all interest across Georgia and the
deep south are greatly encouraged to closely monitor the tropics
over the next several days.
/issued at 126 am EDT Wednesday Aug 24 2016/
potential for some IFR-MVFR ceilings to develop toward daybreak
with maybe some patchy IFR-MVFR vsbys due to fog. Then mainly sct-
bkn 4000-6000 ft clouds. Best chances for convection near the atl
area and north and west. Less so for ahn and mcn. Surface winds light and
variable or light east-southeast then east-southeast 10 kts or less during the day.
//Atl confidence...06z update...
low confidence for thunderstorms to affect atl.
Medium for any IFR-MVFR ceilings this morning.
High for all other elements.
Preliminary point temps/pops...
Athens 88 69 92 71 / 20 5 5 5
Atlanta 88 71 91 73 / 30 10 5 5
Blairsville 82 64 87 67 / 40 10 40 20
Cartersville 88 70 91 71 / 40 10 10 10
Columbus 92 71 93 71 / 30 5 5 5
Gainesville 85 70 90 72 / 40 10 10 10
Macon 91 69 93 69 / 10 5 5 5
Rome 90 70 92 72 / 40 10 10 10
Peachtree City 89 68 91 68 / 30 10 5 5
Vidalia 92 69 93 71 / 5 5 5 10