Scientific Forecaster Discussion
fxus62 kffc 280852
Area forecast discussion
National Weather Service Peachtree City Georgia
352 am EST Tue Feb 28 2017
Short term /today through Wednesday/...
starting out with patchy dense fog concern in parts of central Georgia
given residual moisture from evening rainfall and rapid clearing in
its wake for radiational support. For now has seemed brief enough at
locations not to warrant an advisory but will monitor near term
trends and may need a Special Weather Statement.
Otherwise general chance pops remain the story in far north Georgia
(generally north of Atlanta metro) for this afternoon as another
weak impulse looks to skirt across the upper flow situated across
the Tennessee Valley - should be weaker and limited moisture than
disturbance yesterday. Enough low end instability to keep a slight
chance thunder mention. Cannot argue to clear pops completely
afterward given little change in synoptic setup through tonight.
Increased gradient SW fetch will be kicking in by early Wednesday
ahead of our next main playmaker - a strong frontal system progged
to usher in an increasing chance for severe storms. Forecast has
little change from yesterday with strong shear aided by a 50-kt
850mb jet and 90-100 kts above 700mb. Bulk shear vectors nearly
unidirectional will continue to support a qlcs convective Mode with
damaging winds as the main threat. Still isolated tornadoes possible
with a fairly helicity-rich low level ahead and along the front.
Some guidance indicating between 500 and 1000 j/kg of attainable
instability by Wednesday afternoon in northwest Georgia. Morning cloud cover
trends will be key in how the environment could destabilize out
ahead. Wednesday evening trends below 500 j/kg...though the severe
threat could continue southeastward across the rest of the County Warning Area given
how the storms propagate. Storm Prediction Center day 2 outlook has little change
overall too...with still enhanced risk northwest and slight risk for other
majority of area.
Long term /Wednesday night through Monday/...
the main concern will be the potential for ongoing severe storms
moving into or across NW Georgia to start the long term as a strong
cold front moves across the forecast area Wednesday night.
Storms will end across the area Wednesday night with just a small
chance of light showers over the far se cwa to start Thursday.
Otherwise a dry forecast is in store except for next Monday
where moisture return could lead to some light rain across north and
portions of central Georgia with the highest chances over far northwest Georgia.
Temperatures will be in the process of cooling with the cold front
passage Wednesday night and will be most noticed on Thursday with
high temperatures forecast around normal. The coolest morning looks
to be Saturday morning with forecast lows about 7-8 degrees below
normal then warming through the weekend.
initial MVFR to IFR cigs building into sites from the west along
with potential for MVFR or lower vsbys. Cannot rule out cigs
getting into LIFR or katl being near 400 ft this morning but will
monitor trends if amendment for lower is warranted. Otherwise see
gradual lifting this afternoon and possible scattering out to
mainly Alto deck by 00z Wednesday then another overnight round of
MVFR or lower cigs and reduced vsbys. Winds initially light east-southeast to
calm then southeast 7-10 kts into this afternoon with a south-southwest shift
expected near katl after 19z. Any precip chances for this fcst
cycle should stay north of the sites.
//Atl confidence...06z update...
medium on overall cig trends and morning vsbys.
High on all else.
Preliminary point temps/pops...
Athens 72 59 76 46 / 20 20 50 80
Atlanta 72 61 74 45 / 20 20 60 80
Blairsville 63 54 68 39 / 50 40 80 70
Cartersville 69 59 73 42 / 40 20 80 70
Columbus 78 61 78 49 / 10 10 30 80
Gainesville 67 58 71 45 / 30 20 70 70
Macon 80 59 82 52 / 10 10 20 90
Rome 69 59 74 41 / 40 30 80 50
Peachtree City 74 58 75 45 / 10 10 50 80
Vidalia 83 63 84 56 / 5 10 20 50