Scientific Forecaster Discussion
fxus62 kcae 171810
Area forecast discussion
National Weather Service Columbia SC
110 PM EST sun Dec 17 2017
high pressure will shift off the coast
High pressure will shift off the Carolina coast this afternoon.
There will be increased moisture in the southerly flow on the
backside of the offshore high Monday. Additional rain chances
throughout the week with a weak front across the area.
Near term /through tonight/...
a subtropical ridge will continue to extend into the
southeastern states this afternoon. At the surface, high
pressure will be centered offshore which will promote southerly
flow. Radar indicating showers over west central GA moving to
the northeast. The air mass across the area remains dry with
precipitable water below 1 inch. Expect temperatures this
afternoon to be in the upper 50s to low 60s. Models indicate
increasing moisture tonight mainly mid level through midnight.
There is isentropic lift but with low level dry air expected
limited showers mainly across the south midlands and csra. Any
precip should be light. Will continue slight chance/low chance
pops mainly south. Increasing low level cloudiness expected by
morning. Lows tonight will be warmer than previous nights due to
increasing cloudiness and possible warm air advection...mid 40s
to low 50s.
Short term /Monday through Tuesday night/...
an upper level disturbance falls apart as it moves into the mean
ridge axis over the southeast U.S. A very dry antecedent
airmass over the Carolinas will also inhibit chances of
precipitation with this disturbance.
A second stronger upper level trough is forecast to impact the
region starting on Wednesday. A warm front should be located near
the North Carolina/South Carolina border with overrunning rain.
Temperatures will be well above normal south of the front.
Long term /Wednesday through Sunday/...
a strong disturbance moves off the Carolina coast Wednesday night
with overrunning rain coming to an end. High pressure aloft rebuilds
Thursday into Friday with dry weather and well above normal
A cold front is forecast to sweep into the region this weekend with
a deep and broad upper trough across much of the U.S. Next weekend.
The surface front may become parallel to the upper flow and stall
somewhere near the region early next week.
Aviation /18z Sunday through Friday/...
VFR conditions through the early evening. Stratus/strato-cu
clouds late tonight and early Monday resulting in ceiling
restrictions....MVFR or IFR possible by morning. Patchy fog
possible mainly ags terminal and csra.
Surface high shifting off the coast this afternoon. Satellite
showing mid and high level clouds increasing from the southwest.
A few showers in west central Georgia may move into the area this
evening as isentropic lift and moisture flux increases. However
impacts for terminals will be limited as precipitation will
likely be light and isolated as low levels remain dry. MVFR
strato-cu expected to develop 06z-12z tonight especially in the
csra. MVFR fog also possible. The ceilings may lower after 12z
Monday but confidence low.
Extended aviation outlook...boundary will remain stalled across
the region with rain and associated restrictions at times