Scientific Forecaster Discussion
fxus62 kchs 261449
Area forecast discussion
National Weather Service Charleston SC
1049 am EDT Mon Jun 26 2017
a cold front will linger just offshore through Tuesday. High
pressure is forecasted to pass to our north Wednesday, then move
into the Atlantic during the second half of the week.
Near term /until 6 PM this evening/...
the cold front appears to have made a bit more southeast
progress this morning to just south of Charleston, Walterboro
and Allendale with dewpoints Haven fallen into the 60s and even
50s north of this line. The front should make a bit more
southward progress through the day which will keep the best
moisture/instability/convergence closer to the lower SC coast
into eastern portions of southeast Georgia. Scattered to numerous
showers and some thunderstorms are expected in these areas,
especially south of I-16. Similar to Sunday, high pwats near 2
inches and the potential for convective training could yield
pockets of flooding, mainly south of Savannah in urban and low-
lying/poor drainage areas. An isolated severe storm could also
occur with damaging winds, mainly closer to the Altamaha river. Highs
will warm into the mid 80s for most locations with upper 80s
possible, mainly interior southeast Georgia.
Short term /6 PM this evening through Thursday/...
tonight: convection across the far south will quickly wind down
during the early evening hours. Another weak area of low
pressure is expected to develop along the cold front overnight,
which could push isolated shower activity back onshore along
the beaches early Tuesday. Will show slight chance pops across
the various beach communities to account for this. Lows will
range from the mid-upper 60s inland to the upper 70s along the
Tuesday through thursday: a cold front will linger just
offshore Tuesday. At the coast: chance pops remain in place for
our coastal counties due to their proximity near the
moisture/lift associated with the front. The highest instability
is far offshore, so we're not expecting any significant storms
across the area. Inland: pops are slight chance as drier air
from a surface high to our northwest builds into the area. The
front will be pushed away from our area Tuesday night as the
high moves closer. The center of the high is forecasted to pass
to our north Wednesday. Most of the area should be dry at that
time, but models hint at some moisture/instability across our
southernmost counties in the afternoon/evening hours as some
convergence takes place along the sea breeze. We have slight
chance pops to account for this. The high shifts offshore
Thursday, allowing S to southeast flow to develop late. This will bring
more moisture into our southern counties and further increase
the threat of showers/thunderstorms. High temperatures will be
within a few degrees of normal each day.
Long term /Thursday night through Sunday/...
nearly zonal flow will persist aloft with surface high pressure in
the Atlantic. Southerly flow around the high will advect moisture
into the southeast as an inland trough develops into the weekend.
The result will be the typical summertime shower/thunderstorm
pattern with the coverage and intensity appearing to increase each
day into the weekend.
Aviation /14z Monday through Friday/...
VFR. Risk for showers and tstms will be greatest south of the
ksav terminal this afternoon near a cold front. Probabilities
for impacts are too low justify a mention of thunderstorms in the vicinity or thunderstorms and rain at
Extended aviation outlook: brief flight restrictions are possible
due to showers/thunderstorms Tuesday afternoon/evening and then
again on Friday.
today: north to northeast winds will prevail today behind a
passing cold front. Expect a bit of a surge in winds, up to
around 15 to possibly 20 kt at times. Seas will build a bit but
should stay 3 ft or less.
Tonight: a light northeast flow regime will hold in place with
speeds around 5 kt. Seas 2-3 ft during the evening hours will
subside to 1-2 ft after midnight.
Tuesday through friday: a cold front will linger just offshore
Tuesday, bringing changing wind directions. High pressure is
forecasted to pass to our north Wednesday, causing an increase in
the pressure gradient, which will lead to slightly higher winds and
seas Wednesday and Thursday. Conditions will improve as the high
moves into Atlantic during the second half of the week, allowing the
gradient to decrease.
tides could once again approach shallow coastal flooding
thresholds in the Charleston Harbor with the late evening high
tide cycle. Tide levels at fort Pulaski look to peak just shy of
shallow coastal flooding levels. A coastal flood advisory may be
needed for parts of the lower South Carolina coast, especially
for Charleston County.