Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 171502
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1102 AM EDT Tue Oct 17 2017

.SYNOPSIS...
Strong high pressure will build over the area through next
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Some minor changes with this update.
Clouds: Satellite imagery shows thick clouds hanging around the
coastal counties longer than expected. Inland, skies are clear. The
line between clouds and clear skies is fairly sharp and it`s
shifting eastward. Adjusted the sky forecast to reflect this and
the expected trends.
Temperatures: The aforementioned clouds have held temperatures
down, mainly for the coastal counties. Adjusted the temperature
curves in these locations to reflect this. Also, lowered
temperatures a few degrees in some of these locations as the
lack of sun may make it difficult to get to the 70 degree mark.
Otherwise, no other changes were made.

Rest of today: A 1025-1030 mb high over the central
Appalachians will shift towards the Mid-Atlantic region. This
will result in persistent northeast flow with below normal
temperatures. The pressure gradient associated with the high
will continue to support breezy northeast winds through the
afternoon. Wind gusts should top out around 20 mph in most
areas, with 25-30 mph gusts possible at the beaches.

Lake Winds: Gusty winds persist on Lake Moultrie, but not at
speeds high enough to warrant continuing the advisory.

Tonight: The synoptic setup remains the same as the center of
the surface high sits to the north just in the lee of the
central Appalachians. The forecast is dry and the main story
will be the cool temperatures. The persistent elevated northeast
flow will prevent ideal radiational cooling conditions so
temperatures won`t be as low as they could be under different
circumstance. Forecast lows are in the mid 40s well inland,
ranging to the low to mid 50s closer to the coast.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Strong, dry high pressure will expand southeast across the area
during the period. Weak moisture convergence over the coastal
waters may support isolated showers Wednesday into Thursday. A
building upper ridge Thursday into Friday will yield warming
temperatures and diminishing rain chances over the waters.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A deep layered ridge will maintain mostly dry weather and
seasonable temperatures through Saturday. A southern stream
shortwave will bring increasing moisture and a potential Gulf
surface low into the area early next week. This would be our
next chance for measurable rainfall, potentially Sunday but more
likely Monday into Tuesday.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR. Gusty northeast winds will persist through this afternoon,
then easing during the evening.

Extended Aviation Outlook: VFR.

&&

.MARINE...
Today and Tonight: Strong northeast winds will persist. The
pressure gradient will lower a bit this evening and overnight,
allowing winds/gusts to gradually trend downward. Solid Small
Craft Advisory conditions will remain through the entire period.
The advisory for the Charleston Harbor will run through this
evening. Expect hazardous wind-driven seas, especially beyond 10
nm out.

A persistent NE gradient will continue into Wednesday night,
gradually weakening late week into the weekend as the surface
high builds overhead. Small Craft Advisory conditions expected
to exist over the nearshore waters into Thursday afternoon,
mainly due to seas, with the offshore GA waters seeing SCA
conditions extend into Saturday.

&&

.TIDES/COASTAL FLOODING...
Strong/persistent northeast winds will push higher water levels
to the coast this week. Minor coastal flooding will be possible
around high tides into Thursday or Friday. Coastal Flood
Advisories will likely be needed.

&&

.EQUIPMENT...
Hourly observations and daily climate data from the weather
sensor along Riley Waterfront Park (KCXM) in Downtown Charleston
will not be available until further notice. The cause of the
senor outage is possibly linked to a bad transmitter at the
site. Technicians continue to evaluate the system for a possible
resolution.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents until 8 PM EDT this evening for GAZ117-
     119-139-141.
SC...None.
MARINE...Small Craft Advisory until 5 PM EDT Thursday for AMZ350-352-
     354.
     Small Craft Advisory until 8 PM EDT Friday for AMZ374.
     Small Craft Advisory until 8 PM EDT this evening for AMZ330.

&&

$$
NEAR TERM...
SHORT TERM...
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
EQUIPMENT...



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