Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston SC
655 PM EDT Friday Oct 24 2014
high pressure will prevail through Saturday. A dry cold front will
dissipate over or north of the area Sunday followed by unseasonably
warm high pressure through the middle of next week.
Near term /until 6 am Saturday morning/...
a potent shortwave approaching from the northwest is enhancing a
large batch of altoform and cirriform clouds across the midlands
and Pee Dee early this evening. The tail end of this cloudiness
will skirt the northern half of the forecast area for the next few
hours as it moves east at 40 knots. Expect clear skies to prevail
once these clouds move offshore.
The boundary layer has already decoupled and temperatures are
falling fast in the nearly ideal radiational environment.
Temperatures will likely be held up some for the next few hours
across the north as clouds briefly push through...but this should
not affect overnight lows. Have lowered temperatures slightly in a
number of areas to try to account for mesoscale influences...but
overall the low temperature scheme was not changed too much. Lows
will range from the lower 40s inland to the middle-upper 40s just
inland from the coast with Lower-Middle 50s at the beaches...downtown
Charleston and around the Santee lakes.
Short term /6 am Saturday morning through Monday/...
high pressure will weaken Saturday as a cold front begins to
approach from the northwest but the front will dissipate as it nears
the area early Sunday. High pressure will then return Monday. All in
all dry weather is expected with very limited moisture available.
This will lead to big diurnal temperature ranges...generally 25-30
degrees between overnight lows near 50/lower 50s and highs in the
lower to middle 80s. The onshore flow Monday should keep temperatures below
the record highs in the upper 80s at kchs/ksav and middle 80s at kcxm.
Long term /Monday night through Friday/...
the expansive upper level ridge will slowly shift east while a broad
trough pattern develops mid-week. A weak surface trough may set up
off the Georgia coast Tuesday night into Wednesday night with isolated
showers possible. Large model differences exist Thursday into Friday
regarding an upper vorticity dropping toward the middle-Atlantic region.
There are hints at a cold front moving into the Carolinas Thursday
and moving offshore by Friday morning. However the low and middle
levels do not look very moist so we currently only show slight
chance probability of precipitation Thursday and Thursday night. Fairly warm temperatures will
continue Tuesday through Thursday with highs in the 80s and lows in
the 50s. A cool down is expected Friday with highs in the upper 70s.
Aviation /00z Saturday through Wednesday/...
Extended outlook...there are no concerns.
tonight...light winds will become north and increase to 5-10 knots
overnight as shortwave energy pushes through. Seas will average
Saturday through Wednesday...high pressure to the west will slide
offshore this weekend and persist into the middle of next week. This
will lead to offshore winds becoming onshore Monday with winds
generally 10 knots or less and seas 3 feet or less.