Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 151223

Area Forecast Discussion
National Weather Service Charleston SC
723 AM EST Thu Nov 15 2018

Low pressure will move northeast of the area today with cool
and dry high pressure returning through much of the weekend.
High pressure will generally persist over the southeast states
next week.


Today: A deep mid level cut-off low pressure area between St.
Louis and Memphis is forecast to be ejected more eastward by a
digging short wave across the Northern Plains. The main surface
wave off our coast will reach Northeast NC by late in the day.
Rains will persist through the morning across SC zones but tend
to shift northeast away from the region this afternoon. Across
southeast GA, a punch of strong deep layered drying is forecast
to bring an end to light rains by midday or sooner many areas.
The back edge of nearly saturated 850-500 MB air may takes until
mid afternoon to clear out of Charleston and Berkeley Counties
and some scattered light back-side rains are possible until the
dryer air aloft arrives. Model consensus suggests that if there
is much clearing later today, it would be most likely occur
inland from I-95 and probably so late it would not impact temps
very much. Readings are expected to be chilly as consensus
guidance indicates inland temps may struggle to get out of the
lower 50s or maybe even some upper 40s in some areas.

Tonight: Skies will eventually clear with cold air advection in
the lower levels on tap as high pressure builds east toward the
area. Late night readings across the area will fall into the
mid to upper 30s along with light west to northwest breezes.
We were compelled to introduce patchy frost over much of the
region to the west of U.S. given the anticipated sunrise temps
and a chance that inland sheltered locations decouple late.


Confidence is high this period. Expect improving conditions Thursday
as low pressure moves farther away up the coast. Rain should
generally end from south to north Thursday morning although a few
showers could linger across the SC Lowcountry into late Thursday
afternoon. Instability looks minimal over land but can`t rule out a
few thunderstorms mainly near the Charleston County coast early in
the morning. Otherwise high pressure will build in and prevail
through the end of the week. The main concern late week will be the
potential for some frost Friday and Saturday morning across inland
areas where temperatures could reach the mid 30s. The best chance
for at least scattered frost will likely be Saturday morning though
when winds are lighter.


Dry weather will prevail through early next week as cooler high
pressure moves into the area. A weak area of low pressure may
develop offshore and cause a few showers mainly near the coast.
Temperatures should mostly stay near normal.


The low pressure area offshore was moving up the Carolina coast
this morning and rains on the backside of the system have become
more scattered and light, some drizzle is even possible through
the morning. The primary concern today with be timing the slowly
improving conditions as cigs initialized IFR through the
coastal corridor at daybreak. Forecast soundings suggest cigs
should lift to MVFR at KSAV either late morning very early in
the afternoon at the latest, then clouds scatter out late in the
day as drier air in the low levels filters in. At KCHS, IFR cigs
may last a while longer into the afternoon. Low level west flow
and the arrival of drier air by 21Z today should signal cigs
in the MVFR range briefly before scattering out not long after

An additional concern is LLWS at KCHS and perhaps more limited
risks at KSAV through mid morning.

Extended Aviation Outlook: Flight restrictions, likely below IFR at
times, expected much of Thursday, especially at KCHS. Otherwise no
significant impacts expected through the weekend.


Today: We have SCA conditions that will improve after winds
shift offshore and the waves begin to subside. This will first
occur late morning along the near shore waters of GA and then
southern SC waters early this afternoon. Charleston waters will
tend to be slower to subside and SCAs are forecast to persist
for seas through the afternoon hours.

Tonight: Cold air advection over the waters while high pressure
builds in from the west. We expect decent surges that will keep
conditions in SCA mode over outer GA waters. It is more marginal
near-shore but SCAs are possible in these legs. Seas will be
higher offshore in the northwest flow regime.

Thursday through Sunday: Quite poor marine conditions expected into
early Friday as a storm system moves north of the area. Small Craft
Advisories will likely come down Thursday afternoon for the
nearshore waters but linger through Friday morning for the offshore
GA waters. Otherwise no significant concerns through the end

High surf: A High Surf Advisory remains in effect along the SC
coast for a couple more hours. Shifting wind directions to
offshore will spell an end to the high surf potential after mid


SC...High Surf Advisory until 10 AM EST this morning for SCZ048>050.
MARINE...Small Craft Advisory until noon EST today for AMZ352.
     Small Craft Advisory until 7 PM EST this evening for AMZ350.
     Small Craft Advisory until 10 AM EST this morning for AMZ354.
     Small Craft Advisory until 11 AM EST Friday for AMZ374.


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