Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
808 PM EDT sun Mar 16 2014
Previous discussion... /issued 333 PM EDT sun Mar 16 2014/
Short term /tonight through Monday night/...
band of heavier precipitation shifting east/south of the forecast
area this afternoon with a bit of a dry slot impacting the majority
of the forecast area into the evening. However...with the upper
trough axis remaining west of the state through the day Monday I
have retained fairly high probability of precipitation through the forecast period. Still
some heavy rain potential in the far south/southeast this evening
until the axis of deeper moisture shifts east/south. Still marginal
instability for thunderstorms outside of The Wedge...but better
low-level and medium depth shear is already shifting south and east
of our forecast area. I will be carrying slight chance/chance for
thunder outside of The Wedge dominated areas into the evening. The
Wedge should hold on from the metropolitan area northeast and east...even
in the face of the approaching surface low. If fact models are
fortifying The Wedge somewhat late in the period as the surface low
re-develops off the South Carolina coast. Source airmass for The
Wedge is relatively mild so we should not see any extreme effects in
our northeast/east central counties.
Only a few minor hydrologic issues have cropped up from todays rain
and additional quantitative precipitation forecast totals through Monday are more modest as the
Richer moisture shifts east and precipitation becomes more scattered
Long term /Tuesday through Sunday/...
have made little change to the forecast as looks to be on track
and cannot justify notable adjustments. Previous discussion
Previous discussion... /issued 401 am EDT sun Mar 16 2014/
Long term /Monday night through Saturday/...
models continue to agree on a strong short wave traversing the
state Monday night...while a surface low pushes off the southeast
Georgia coast. The departing surface low will help strengthen a cold
wedge of high pressure nosing down the eastern Appalachians...
resulting in a cool... cloudy Tuesday... with patches of
overrunning light rain... especially along the eastern half of the
state. The upper disturbance pushes east Tuesday afternoon... but
a moist southerly middle level flow will continue to overrun the
cool northeast surface flow... warranting a slight chance of rain
across north Georgia Tuesday night. Long range models continue to show
a weak cold front possibly bringing a low chance of rain to the
area Wednesday-Wednesday night with some difference in timing.
Prefer the faster and more persistent GFS for now with high
pressure and dry conditions on tap for Thursday and Friday. European model (ecmwf)
and GFS show another cold front pushing into the area on
Saturday. Will show a chance of showers on Saturday. No thunder
is expected at this time with lack of instability and strong
upper support noted.
yet another complex scenario across the terminals this evening
with warm front extending from Columbia through north Georgia
including the atl terminals and then into a surface low over
northern Alabama. Actually have had some clearing over Alabama and
now the development of isolated thunderstorms in the area.
Question becomes does this activity shift over our area or does it
dissipate and low ceilings and east winds of wedge prevail. Given how
close we are to sunset...expect storms to remain west of the area
and low ceilings to remain in place for the northern terminals. Will
also see a return to some light rain as well. To the south...more
problematic but anticipate periods of MVFR and IFR and then
becoming all IFR during the overnight period.
//Atl confidence...00z update...
medium on all elements.
Preliminary point temps/pops...
Athens 46 47 39 49 / 80 60 60 40
Atlanta 50 54 42 55 / 60 60 50 20
Blairsville 45 48 40 51 / 70 50 50 30
Cartersville 51 55 41 56 / 60 50 50 20
Columbus 57 64 47 62 / 70 60 50 20
Gainesville 45 45 40 51 / 70 50 60 40
Macon 55 62 44 56 / 90 70 60 30
Rome 50 53 41 57 / 60 50 50 20
Peachtree City 51 57 43 55 / 60 60 50 20
Vidalia 58 62 47 58 / 90 80 70 40