Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
403 am EDT sun Jul 13 2014
Short term /today through Monday/...
high pressure continues across much of the forecast area this
morning. An upper level shear axis remains across
Mostly clear skies expected across much of the County warning forecast area through the
early morning...some low clouds/stratus are possible across the
southern County warning forecast area and may impact the mcn area and southeast through sunrise.
Any low clouds/fog should burn off by middle morning but haze may
linger a few more hours.
Precipitation coverage will be much like Saturday. The highest probability of precipitation should
be across the higher terrain of northern Georgia...and nearest the shear
axis in the southern County warning forecast area. Bl winds have picked up from
yesterday...so storm movement should limit locally heavy rainfall
along with the lower precipitable waters . The synoptic pattern begins to shift
slightly on Monday as a frontal boundary approaches from the north.
Slightly higher probability of precipitation across northern Georgia will be needed along with
increasing cloud cover.
Temperatures today will also continue slightly above normal with most
locales in the lower 90s...with 80s in the higher terrain.
Long term /Monday night through Saturday/...
still on track for a brief shot of cooler/drier air middle of next
week. Medium range models remain in good agreement though the 00z
European model (ecmwf) a little slower with surface front moving into north Georgia Tuesday.
Widespread rain showers/thunderstorms and rain likely on Tuesday...have gone above MOS guidance
which is woefully underdone...went closer to HPC guidance and
sref quantitative precipitation forecast-based pop. Should see rapid clearing Tuesday night. Severe
storms not out of the question but with widespread clouds and
precipitation...models having a tough time forecasting any significant
instability. 00z GFS has MLCAPE over 1500 j/kg over middle Georgia
ahead of precipitation areas. Vertical wind shear weak as expected for
July frontal passage. Precipitable water values high but not abnormally so. Will continue to
monitor model forecasts but for now...no clear sign of significant
hazardous weather appearant.
Moisture aloft quick to return Thursday night/Friday but low level
moisture thankfully remains slower to return. Appears diurnal
convection Friday/Sat will remain less intense based on model
low level moisture and resulting buoyancy forecasts. Subjective thoughts
are this seems a little heavy handed by models and that more low
level moisture through evapotranspiration and advection likely.
Have kept 20-30 probability of precipitation for convection in forecast through Sat.
only isolated probability of precipitation expected at atl today. Best precipitation coverage should
be across the higher terrain of north Georgia and across south central Georgia.
Low clouds and fog not expected to impact the airfield overnight.
Diurnal cumulus will settle between 4kft and 5kft during the
afternoon. A front will begin to approach later on Monday
afternoon...and probability of precipitation should increase slightly along with cloud
cover. Winds will be tricky today. Light and variable/slightly southeast
flow will continue overnight. Models are bringing the winds around
to a little west of south by middle morning.
//Atl confidence...06z update...
medium confidence on winds today. High confidence remaining
Preliminary point temps/pops...
Athens 93 73 95 73 / 20 20 40 30
Atlanta 92 74 93 73 / 20 20 40 40
Blairsville 86 67 86 69 / 40 20 60 60
Cartersville 93 73 93 73 / 40 20 60 60
Columbus 94 74 94 74 / 20 20 30 30
Gainesville 91 72 92 72 / 30 20 50 50
Macon 93 74 95 73 / 30 20 30 30
Rome 93 72 94 72 / 40 20 60 70
Peachtree City 93 72 93 71 / 20 20 40 30
Vidalia 91 73 94 76 / 40 30 30 20