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Area forecast discussion...updated 
National Weather Service Peachtree City Georgia
1037 am EDT Thursday Sep 18 2014

Update...
current satellite trends show that the cloud deck is breaking up
across the metropolitan area. Expect the current forecast to be on track.
Hires guidance suggests the threat of thunder today remains low.
However with The Wedge in place...low level moisture and a ripple
in the upper level flow...thunder and rain cannot be ruled out.
Especially across the eastern part of the County Warning Area. No changes to the
forecast were made and no further updates are expected at this time.

Arg

&&

Previous discussion... /issued 735 am EDT Thursday Sep 18 2014/

Short term /today through Friday/...
/issued at 439 am EDT Thursday Sep 18 2014/
latest surface analysis shows a nearly stationary cold front near an
Americus to Swainsboro line where it will likely meander today.
Models hint at a series of disturbances developing a wave along the
frontal boundary that could help provide a focus for at least
isolated convection across mainly the southeast and east central
portions of the state this afternoon and evening. Local hires model
precipitation fields also suggest this potential. Will continue to show a
slight chance of showers and thunderstorms across the eastern half
of the forecast area for today. A cold dome of high pressure
currently across the Ohio and Tennessee valleys will drift east and
establish a cool easterly flow tonight. This will spread ample low
clouds into the state overnight... then set up a cool reinforcing
wedge of high pressure across much of the state on Friday. Models
also show an upper disturbance settling over the state on Friday.
This has the potential to enhance clouds and rain chances on Friday.
Although cannot rule out an isolated thunderstorm over the far south
and southeast zones Friday afternoon... will only mention rain
showers for now as model instability fields suggest any thunderstorm
threat will be closer to the Georgia coast and further south into
Florida.

As for temperatures... the cool northerly flow and increasing clouds will
result in near or slightly cooler than normal highs for today and
tonight. The cloudy easterly flow and spotty showers should result
in cooler than normal highs on Friday. A mav and met blend for temperatures
and probability of precipitation looked reasonable with uncertainty on timing and coverage
of clouds and rain potential...especially tonight and Friday.

39

Long term /Friday night through Wednesday/...
/issued at 439 am EDT Thursday Sep 18 2014/
the extended forecast starts out with a slightly the drier
airmass over the region and a wedge of high pressure building in
from the NE. This wedge will bring Atlantic moisture back in across
the area with mainly overcast skies for the weekend. There may be a
few showers and thunderstorms across central Georgia but not much
expected. This wedge is expected to continue across the region
through Sunday night before another frontal system moves in from
the northwest Monday morning. As the next frontal system moves into north
Georgia the frontal boundary weakens a bit with the majority of the
moisture staying north and east of the state. Have decided to
continue with only a slight chance of showers and thunderstorms
Sunday night and Monday. Once this next front exits the state
Monday night...another dry airmass and high pressure ridge build
in from the Great Lakes states through day 7.

01

Aviation...
12z update...
LIFR to MVFR ceilings have become widespread for areas mostly east of
atl this morning... but these ceilings should spread into atl at least
temporary between 12-14z this morning. Then scattered middle clouds prevail
through the afternoon. Models show a cool easterly wedge setting up
by 06-09z Friday...with moisture fields showing MVFR-IFR ceilings spreading
back in over atl between 07-09z Friday. Cloudy wedge should persist
through Friday evening with patches of -ra Friday morning... then isolated
to scattered showers Friday afternoon. Current light north-northeast winds swing back north-northwest
by 17-18z today... then back north-northeast between 04-06z Friday night. Speeds
will be 4-7kts.

//Atl confidence...12z update...
medium on timing of wind swings and low clouds this morning and
tonight. High on remaining elements.

39

&&

Preliminary point temps/pops...
Athens 83 64 81 63 / 20 20 20 20
Atlanta 84 66 82 65 / 10 10 20 10
Blairsville 78 59 77 58 / 10 10 20 20
Cartersville 84 60 82 65 / 10 10 20 10
Columbus 89 67 86 68 / 10 10 20 10
Gainesville 81 65 79 63 / 20 10 20 20
Macon 87 65 84 65 / 20 20 20 20
Rome 85 59 83 65 / 10 10 20 10
Peachtree City 84 61 83 64 / 10 10 20 10
Vidalia 87 67 84 67 / 20 20 30 20

&&

Ffc watches/warnings/advisories...
none.
&&

$$

Short term...arg
aviation...arg

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