Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston SC
705 am EDT Thu Oct 27 2016
high pressure will prevail through the weekend. A
backdoor cold front will move through the Carolinas on Monday,
followed by high pressure into the middle of the upcoming week.
Near term /through tonight/...
the pattern aloft will feature nearly zonal flow this morning as
a trough approaches from the west. The trough is forecasted to
weaken, with the bulk of it's energy passing to our north this
afternoon through tonight. At the surface, broad high pressure
offshore will be pushed out to sea in the afternoon by low
pressure moving from the Great Lakes into the northeastern states.
This low will drag a cold front through the Tennessee Valley this
afternoon, but it is expected to remain north of our area through
tonight. An increase in upper level moisture today will equate to
more high clouds. However, the forecast remains dry due to the
lack of significant forcing. Thickness values and some
compressional warming ahead of the front support temperatures
rising to around 80 degrees in the afternoon. Lows will be in the
mid to upper 50s inland and the lower 60s along the immediate
Short term /Friday through Sunday/...
friday: warm and dry weather will continue as a trailing cold front
from a low pressure area along coastal New England sags into the
Carolinas and lacks moisture and convergence. Mid level subsidence
and height rises will build by afternoon while an upper jet segment
is forecast to move off the southeast U.S. Coast. These factors
should result in a decrease in high clouds with only a scattering of
diurnal cumulus/stratocu. We expect temps will reach the lower to
mid 80s most areas.
Saturday and sunday: an expansive deep layered ridge will build
across the southern states. This will maintain a warm and dry
weather pattern. Both days could see high temps not far off some
records in spots as sunshine prevails for the weekend. Highs will
be in the mid 80s with lows most areas in the 55-60 degree range.
Long term /Sunday night through Wednesday/...
expansive deep layered ridging looks to persist through the
period across the southeast states. During Monday or early
Tuesday, a dry backdoor cold front will pass south through the
forecast area while surface high pressure builds south from the
mid-Atlantic region. The European model (ecmwf) suggests a few coastal showers are
possible with shallow moist onshore flow, but we maintained a dry
forecast as upper ridging only strengthens with time while
moisture looks too shallow to expect any precipitation. Deep
layered ridging will persist past mid week with any rain chances
beyond the forecast period. Very warm temps will prevail, most
days in the lower 80s with mild lows in the upper 50s on average.
Aviation /12z Thursday through Monday/...
mifg at the terminals until about 13z due to low level moisture.
Otherwise, VFR will prevail through 06z Friday. Small chances for
MVFR or lower vsbys Friday morning, especially in the 08z-12z/28
Extended aviation outlook: VFR conditions expected to prevail
through this weekend with low probabilities for late night or
early morning restrictions in patchy fog prior to the weekend.
today and tonight: a weak pressure gradient will generally keep
winds under 10 kt across most of the waters. Seas will average 2-4
Friday through sunday: high pressure will be the primary feature
across the local waters through the weekend. A weak front will turn
flow northeast Friday night and early Saturday with surging less
than 15 kt. The weekend will then feature plenty of light and
variable flow and seas averaging 2 ft near shore with 2-3 ft
more probable near The Pilot buoys.
Early next week, a backdoor cold front will drop through the waters
and we could see some moderate northeast surges after Monday.