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Area forecast discussion
National Weather Service Charleston SC
743 PM EDT sun Mar 26 2017

Atlantic high pressure will weaken early this week. A weak cold
front will stall over the area during the middle of the week,
then shift back north as a warm front Friday. Another cold front
should move through Saturday or Saturday night followed by
drier high pressure Sunday.


Near term /until 6 am Monday morning/...
early this evening: lingering convective clouds will dissipate
with the loss of heating and much of the overnight is expected
to bring mostly clear skies. Then late tonight, chances for fog
increase, especially inland and west of I-95. Have expanded
patchy fog in the forecast. Could even see some stratus in areas
mainly closer to the midlands. Lows should be similar to last
night, perhaps a degree or two warmer.


Short term /6 am Monday morning through Wednesday/...
Monday and tuesday: weak isentropic lift ahead of a low pressure
system passing to the north will help produce some cloud cover as
moisture deepens over the southeast. However, a light onshore flow
will gradually veer to southwest through Tuesday, suggesting warm
temps well ahead of a cold front approaching from the northwest. In
general, afternoon temps will peak in the lower 80s each day away
from the coast. Temps should be warmer on Tuesday as the southwest
sfc wind and partial downsloping wind aloft hold the seabreeze to
the coast for a longer period than that on Monday. Given these temps
and increasing levels of moisture, a slight chance to chance of
showers will remain in the forecast. A few thunderstorms will also
be possible during peak heating, mainly inland on Monday and in
northern locations Tuesday where instability levels and mid lvl
forcing associated with a h5 shortwave are greatest. Overnight lows
will remain mild Monday and Tuesday nights. In general, temps will
only dip into the upper 50s and lower 60s.

Wednesday: a dry cold front will approach from the northwest well
after its parent low shifts off the mid-Atlantic and northeast
coast. The amount of separation between the front and the parent low
suggests the front will stall over or near the area while it becomes
aligned parallel to the mid/upper lvl flow. Ahead of the front,
temps will remain considerably warm under a mid/upper lvl ridge of
high pressure building aloft. In general, temps should peak in the
low/mid 80s away from the immediate coast.


Long term /Wednesday night through Sunday/...
the stalled front should shift north as a warm front Friday followed
by a cold frontal passage Saturday or Saturday night. Drier high
pressure should then return later in the weekend. Showers and
thunderstorms will be possible, mainly Thursday through Friday
night, with temperatures running above normal through at least


Aviation /00z Monday through Friday/...
VFR conditions are expected to prevail through 00z Tuesday.
Expect to see some patchy fog develop close to sunrise inland
of the terminals tonight. Ksav seems to have the best chance for
fog, but it will likely just be shallow ground fog and the
forecast remains VFR. Otherwise, another round of isolated
showers Monday afternoon, though current indications show these
staying inland of the terminals.

Extended aviation outlook: mainly VFR. Brief flight restrictions are
possible each afternoon with showers and/or thunderstorms this week,
best chances Thursday or Friday. Low probability of restrictions due
to early morning low clouds and/or fog.


tonight: south to southeast winds will persist as Atlantic high
pressure remains well offshore. Speeds will remain 10 kt or less
with seas 2-4 ft nearshore waters and 4-5 ft offshore waters.

Monday through friday: winds/seas are expected to remain below Small
Craft Advisory levels as high pressure slowly weakens ahead of weak
cold front arriving from the northwest Wednesday. However, winds
should peak near 15-20 kt at times Tuesday ahead of the front while
seas build up to 3-5 ft, highest in offshore Georgia waters. The
front will transition into a warm front as it moves back north
Friday. Seas could reach 6 feet near the Gulf Stream through Tuesday
due to swells from low pressure well offshore. Advisories will be
possible across the outer Georgia waters through Tuesday and then for
more of the area Thursday night/Friday as strengthening southerly
winds build seas to 6 feet again.

Rip currents: a moderate risk of rip currents is in the forecast
along all beaches Monday due to long period swell of 2-3 feet
from the southeast coinciding with the upcoming new moon. The
combination of long period swells, astronomical influences and
onshore winds will support an enhanced risk for rip currents
through mid week.


Chs watches/warnings/advisories...



Near term...bsh

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