Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
1238 am EST sun Feb 14 2016
Previous discussion... /issued 1010 PM EST Sat Feb 13 2016/
current forecast is still on track so no updates expected.
Previous discussion... /issued 756 PM EST Sat Feb 13 2016/
Short term /tonight through Sunday night/...
looks like the short term will start off quiet...but things will
change Sunday night into Monday morning. Currently...high
pressure is centered over the Great Lake states will continue
moving east into the Middle Atlantic States through Sunday
afternoon. This ridge will set up a wedge down the eastern
Seaboard locking in cold air across north Georgia ahead of the
next weather system. This wedge is expected to begin eroding away
as the next system pushes into north Georgia but there will still be
some cold air in place as it does. This next system is currently
developing over the northern plains and slide southeast over the next 48
hours as the main low pressure center moves east into the Great
Lake states Sunday night/Monday morning. The main cold front begins
pushing deep moisture into north Georgia between 00z- 06z Monday with the
bulk of it moving into the state Monday afternoon. Areas across
north Georgia...especially the NE Georgia mountains...will see a mix of
rain/freezing rain/snow Sunday night into Monday afternoon. We
have issued a Winter Storm Watch beginning Sunday night continuing
through Monday evening.
Long term /Monday through Saturday/...
again a complicated forecast for the early part of the long term
with just minor changes from the previous forecast. The biggest
difference is the timing of the onset of the precipitation. All models are
delaying the onset from the previous forecast. This will play a role
in the amount of cooling in The Wedge area. The surface high will be
transient and also the upper support for The Wedge will weaken
Sunday night and Monday. Therefore the only real support for holding
The Wedge and colder air will be evap cooling from the
rain...however this will be delayed by a few hours which will be
enough for temperatures to rise a couple degrees higher than previously
expected. Just these couple of degrees could make the difference
between freezing rain and r. At this point it is too far out to say one way or
the other and therefore will maintain a pretty consistent forecast
with p-type. It will start with a r/zr/S mix across north Georgia
translating to a r/freezing rain mix across northeast Georgia with rain over the
rest of the County Warning Area Monday afternoon. By 00z Tuesday...there could be
isolated pockets of freezing rain...but most areas should be all rain. This is
good as the heavy rain will be moving into the County Warning Area after 00z Tuesday.
Having said that...will issue a Winter Storm Watch from 06z Monday to
00z Tuesday for much of northeast Georgia. This will include the north and
northeast atl metropolitan areas but not the city of atl. Ahn is also not
in the watch.
The system will pull rapidly out of the County Warning Area late Monday
night/Tuesday...and there could be a brief mix of r/S in the north
Tuesday morning but no additional accumulation expected. A fast
moving upper system will be pulling further north but the tail end
could move across extreme north Georgia Tuesday night and this will bring
a chance of r/S...but no significant accumulation is expected at
Temperatures will warm rapidly after the Tuesday night system with most
areas into the 60s by Thursday.
initial VFR conditions should persist through the afternoon
Sunday...while gradual decrease in conditions expected Sunday
night into Monday with MVFR ceilings building in after 04-06z for most
sites and then lower into the day Monday as precipitation and
overrunning moisture becomes more widespread. For now have
introduced prob30 for -ra at end of forecast period for katl early
Monday morning. Any wintry precipitation potential looks to remain north
and east of katl though kahn could have a mix of -ra and -fzra
Monday morning. Winds should be shifting NE to east this morning
then be predominantly east-southeast 7-10 kts later this afternoon.
//Atl confidence...06z update...
medium on late period precipitation.
High on all else.
Preliminary point temps/pops...
Athens 42 30 41 38 / 5 40 80 90
Atlanta 44 34 44 39 / 5 40 90 90
Blairsville 35 28 36 33 / 20 80 100 90
Cartersville 44 33 43 35 / 10 60 100 90
Columbus 52 39 59 43 / 5 20 80 80
Gainesville 39 30 36 34 / 5 50 90 90
Macon 50 36 59 43 / 5 20 80 80
Rome 44 34 43 35 / 20 80 100 80
Peachtree City 47 33 48 37 / 5 30 90 90
Vidalia 49 39 65 49 / 5 10 70 70
Winter Storm Watch from late tonight through Monday evening for
the following zones: banks...Barrow...Cherokee...Dawson...