Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 161150
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
750 AM EDT Wed Oct 16 2019

.SYNOPSIS...
A cold front will move through this evening, followed by dry
high pressure Thursday and Friday. A storm system originating
in the Gulf of Mexico should bring our area unsettled weather
this weekend, followed by another cold front the first half of
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
At sunrise: The heaviest precipitation shield has moved through
and off to the east. Now all that is left behind is isolated to
scattered showers. From mid morning onward, model time heights
and soundings show a distinct drying trend in the mid and upper
levels which will shut off the generation of widespread
significant rainfall. However, into the afternoon, scattered
showers are expected with lingering low level moisture, forcing
from the trough aloft, and some weak instability. Don`t think
there will be enough for thunder, but showers look quite
certain. Therefore, rain chances remain in the 20-30 percent
range through the afternoon. The actual cold front shows up well
in thetaE plots, and we will remain in the warm sector ahead of
the front through the day. With decreasing clouds and
increasing sun, we should still be able to get highs into the
low 80s, with some chance for mid 80s as well. Winds will turn
more westerly by the afternoon with frequent gusts into the
20-25 mph range.

Tonight: The cold front will begin crossing the forecast area
this evening and should be solidly offshore by the early morning
hours. Skies will clear and much cooler/drier air will filter
in. Look for lows to fall into the upper 40s well inland,
ranging to the mid 50s right at the coast.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Thursday: A mid-level trough is expected to be along or just
off the East Coast while ridging builds over the Central U.S.
and MS Valley. Broad surface high pressure initially centered
over Arkansas in the morning will move over the TN Valley in the
afternoon, prevailing into the evening and overnight. Its
periphery will stretch into our area, bringing subsidence, dry
conditions, and mostly sunny skies. The cooler airmass will make
daytime temperature feel more like fall for a change. Highs
will struggle to make it to 70 degrees in our SC counties, and
the mid 70s in our GA counties. Lows will be chilly, falling
into the 40s across most of our inland locations, warmer along
the immediate coast.

Friday: A mid-level trough initially located off the East Coast
will get pushed away by a strengthening ridge approaching from
the west. The ridge should move over the East Coast overnight.
Broad surface high pressure initially centered along the central
Appalachians will shift eastward into the afternoon and
overnight. Its periphery will stretch into our area, bringing
subsidence, dry conditions, and mostly sunny skies. High
temperatures will be similar to Thursday, mainly due to
northeast surface winds. Overnight is when things start to
change as moisture associated with a system in the Gulf of
Mexico starts creeping into our area. Models are in decent
agreement indicating showers making their way into our area,
mainly south of I- 16 after midnight. We have chance POPs there,
but they will need to be adjusted more based on
timing/intensity refinements. With increasing clouds, low
temperatures should be a few degrees warmer than the previous
night.

Saturday: A mid-level ridge along the East Coast will slowly
drift offshore. The 00Z models made quite a swing, and they all
seem to have hit in the same general direction. They now show a
storm system originating in the Gulf of Mexico with its low
moving onshore along or near the FL Panhandle later in the day.
The NHC is monitoring this system for potential development.
Even if it does develop into something, it`ll be quick to move
onshore and transition to a rain- making system. We only have
chance POPs at this time, mainly because we didn`t want to go
too much higher than all of our neighbors. But if the trends
continue, then these POPs will have to be raised substantially.
It`ll depend on the exact location of the system and its overall
intensity.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
Focus will initially be on a storm system moving into or nearby
the FL Panhandle Saturday night, then moving over or nearby our
area Sunday into Monday. Models are in pretty good agreement
showing a wide swath of rainfall during this time period across
the Southeast. Though, they differ a bit on rainfall amounts and
locations with the highest amounts, which is to be expected
this far out. Once this system moves away later Monday a cold
front is forecasted to approach on Tuesday, bringing another
batch of rain. Overall, we should expect a wet long term. POPs
may need to be raised much more than we`re currently showing.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Flight categories are mainly in the MVFR range and should stay
there through mid morning through a combination of ceilings and
visibility in passing showers. By mid to late morning, VFR
conditions should return either through a lifting of the ceiling
or scattering of the deck. Through the day, showers will be
possible as well as gusty southwest winds into the 20-25 knot
range. Overnight, clear skies will prevail with northwest winds.

Extended Aviation Outlook: VFR Thursday and Friday. A storm
system originating in the Gulf of Mexico is expected to bring
flight restrictions this weekend.

&&

.MARINE...
Today: Conditions are quickly deteriorating this morning as a
surface low develops across southeast Georgia. This feature will
track to the northeast along the coast and bring quickly
increasing winds to the local waters this morning. Wind speeds
20-25 knot with gusts to 30 knots are expected across all waters
outside of the Charleston Harbor. Winds will remain elevated
through the day, with a brief lull this evening ahead of an
approaching cold front. Small Craft Advisories remain in effect
for all waters, and an advisory has been hoisted for the
Charleston Harbor that runs through the afternoon. Also this
morning, areas of moderate to heavy rain will pass through the
waters and lead to reduced visibility.

Tonight: The cold front will move into the waters this evening,
pushing well offshore through the overnight. Northwest winds
should be primarily in the 15-20 knot range in the cold
advection, but a few gusts to 25 knots will be possible
especially in the outer Georgia waters. The advisory for the
outer Georgia waters has been extended through 2 am.

High pressure will bring tranquil marine conditions Thursday
and Friday. A storm system originating in the Gulf of Mexico is
expected to move onshore along or nearby the FL Panhandle the
first half of the weekend, then move over or nearby our area
early next week. Depending on the track and overall intensity of
this system, Small Craft Advisories may be needed.

&&

.TIDES/COASTAL FLOODING...
Tidal departures have quickly increased and it looks like the
tide will peak right at or just above 7 ft MLLW. Issued a
Coastal Flood Advisory through noon. High tide is around 10 am.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until noon EDT today for SCZ048>050.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for AMZ330-
     352-354.
     Small Craft Advisory until 8 PM EDT this evening for AMZ350.
     Small Craft Advisory until 2 AM EDT Thursday for AMZ374.

&&

$$

NEAR TERM...BSH
SHORT TERM...MS
LONG TERM...MS
AVIATION...BSH/MS
MARINE...BSH/MS
TIDES/COASTAL FLOODING...


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