FXUS62 KCHS 261926
Area Forecast Discussion
National Weather Service Charleston SC
326 PM EDT Wed Apr 26 2017
A weak disturbance is expected to affect the area Thursday night,
followed by high pressure Friday into the weekend. A cold front will
affect the area Monday and Monday night before high pressure
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Surface low pressure will track across the Heartland, sweeping
the associated cold front across middle TN by sunrise Thursday.
Return flow across the CWA will remain steady through the
overnight hours. Overall, sky conditions are expected to remain
clear to mostly clear. However, higher clouds should begin to
arrive from the west during the pre dawn hours. Using a blend of
temperature guidance, low temperatures should range in the low
to mid 60s, with upper 60s at the beaches.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
The Bermuda High will begin to build back over the region Thursday
and the forecast area will remain situated under its fringes through
at least Saturday. A positively-tilted shortwave aloft will track
near the forecast area Thursday as it pulls north and east. The
right entrance region of an associated 500-mb jet streak will
approach the forecast area Thursday afternoon but reasonable model
agreement suggests the best forcing will remain inland of our
forecast area. Prognosed upper-level divergence supports this as
well but the preponderance of the evidence indicates that a few
showers and/or thunderstorms could form Thursday afternoon and
evening, primarily inland and along the seabreeze.
Surface high pressure will strengthen under a building ridge Friday
into Saturday suggesting dry conditions will prevail, while flow
around the Bermuda High carries warm, moisture-laden maritime air
into the forecast area. This will result in temperatures several
degrees above normals, in the upper 80s to lower 90s away from the
coast during the day, and cooling only into the upper 60s to lower
70s at night.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The pattern shifts during the long term as a large upper trough
shifts east and a cold front sweeps through Monday and Monday
night. A few showers possible inland on Sunday as some upper
vorticity energy moves through, but the best rain chances will
be Monday and Monday night.
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR through 18Z Thursday.
Extended Aviation Outlook: Expect VFR conditions to prevail at both
Tonight: The marine zones will remain situated between high
pressure over the western Atlantic and a cold front situated
across the MS River Valley. The pressure pattern will provide
the region with generally S flow around 15 kts, turning to the
SSW after midnight. Wave heights are forecast to be 2-4
ft within 20 nm and 4-5 ft beyond 20 nm.
Building Atlantic high pressure will maintain generally southerly,
onshore flow from Thursday through Sunday. The pressure gradient
will briefly tighten as high pressure initially builds into the
area, and this will result in slightly elevated wind speeds later
Thursday, though speeds do not appear to reach small craft advisory
criteria at this time. Winds nearest the coast will likely tip
southwest or even west-southwest overnight each night as a land
breeze develops, but will return southerly with daytime heating.
Seas will generally remain 2-4 ft, with some 5 feet seas building in
offshore as early as Sunday. Strengthening southeast flow ahead of a
cold front Monday will likely result in Small Craft Advisory seas
over most of the waters starting Sunday night and persisting into
Rip Currents...The combination of swell impacting the beaches, an
afternoon sea breeze, and the upcoming Perigean Spring Tide will
generate a Moderate Risk of Rip Currents into Thursday.
The upcoming Perigean Spring Tide and recent elevated
departures will allow for coastal flooding with this evening's
high tide. A Coastal Flood Advisory is in effect for all of the
coastal counties. Elevated tides are expected to continue
through Saturday, so more advisories will likely be needed with
each evening high tide.
GA...Coastal Flood Advisory from 7 PM to 10 PM EDT this evening for
SC...Coastal Flood Advisory from 7 PM to 10 PM EDT this evening for
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