525
FXUS62 KCHS 081226
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
726 AM EST Fri Nov 8 2024

.SYNOPSIS...
A weak front will slowly move south across our region through
tonight, becoming located south of our area by late Saturday.
High pressure will then prevail until a cold front moves
through Monday night into Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early morning update: Pesky light showers continue to percolate
across parts of southeast Georgia and pops have been extended
accordingly. Otherwise, dense fog remains fairly widespread
across the region with no changes to the forecast in that
regard.

Previous discussion...
Overnight composite analysis reveals a flattened upper level
ridge across the southeast and Florida Peninsula region over top
now major Hurricane Rafael in the central Gulf. Envelope of
deep tropical moisture around Rafael still extends up through
the southeast coastal areas although PWAT values across the
forecast area have eased back just a bit (1.74" on CHS 00Z
sounding). Weak inverted surface troughing is still evident
across southeast Georgia with enough low level convergence to
continue kicking of light showers through the far southern part
of the CWA. Outside of the light shower activity, dense fog has
developed over a decent portion of the CWA.

Upper level ridging will remain more or less fixed across the
southeast region through tonight while strengthening surface
high pressure builds across the Great Lakes/Ohio Valley and down
into the southeast.

Today: First off, given the coverage of dense fog, a Dense Fog
Advisory has been issued with the early morning forecast
package, valid through 10 am. Given light winds and weaker early
November sun, it will take several hours to erode/lift the fog
and stratus, and some fog could linger over the nearshore waters
through a good part of the day.

Meanwhile, with the lingering high dewpoints and slow heating,
isolated showers may bubble up across the region this afternoon.
Isolated pops will be maintained with the early morning
forecast.

Tonight: Any shower activity will fade by evening leaving quiet
conditions for the night. Again, light/calm winds...wet grounds
and high dewpoints will lead to some fog development and another
Dense Fog Advisory could be needed.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Saturday: The mid-levels in the morning will consist of a broad ~590
dam High centered over FL, with a ridge axis stretching north into
the Great Lakes Region. As time progresses, the High will slowly
shift eastward, along with the ridge axis, which should be located
over the East Coast late at night. At the surface, a weak cold front
should be near our SC/GA border in the morning. It`s forecasted to
move south during the day, becoming located south of our area during
the evening and overnight hours, while troughing develops just
offshore. Additionally, High pressure will pass to our north and
northeast. The highest moisture values (PWATs >1.5") should stay
just south of the front. All of the synoptic models generally have
isolated to maybe scattered showers forming south of the Savannah
River by the afternoon and persisting into the evening and
overnight. The long-range CAMs point towards minimal coverage. We
leaned more towards the synoptic models. QPF should be minimal.
Across our SC counties, it should remain dry. High temperatures
should be in the 70s. But it`s possible a sharp gradient could setup
between our northern and southern zones due to northeast surface
winds and clouds across a good portion of our area. Lows will range
from the lower to middle 50s far inland, to the lower 60s at the
beaches and near the Altamaha River. Additionally, winds will be
gusty at the beaches.

Sunday: A mid-level High will be located off the East Coast of FL in
the morning, with a ridge axis stretching north over the rest of the
East Coast in the morning. Both will shift offshore as time
progresses. A stationary front will be located just south of our
area in the morning, while troughing is just offshore. Additionally,
High pressure will be centered off the Northeast U.S. The High will
quickly shift further offshore. This will cause the front to quickly
lift north during the afternoon, becoming located north of our area
in the evening. Also, another front will be approaching from the
west and northwest, becoming located generally over the spine of the
Appalachians late at night. As the front lifts north it`ll bring a
plume of moisture with it (PWATs ~1.75"). Likewise, models are in
fairly good agreement indicating isolated to scattered showers
initially south of the Savannah River, shifting north across our
entire area during the evening and persisting into the overnight.
We`ll note that some of the models do hint at decent coverage and
with a bit more QPF. We went with slight chance POPs to try to match
with our neighbors, but wouldn`t be surprised if both POPs and QPF
have to be raised quite a bit with future forecasts. Highs will
generally be in the 70s. Lows will range from around 60 degrees far
inland to the upper 60s near the beaches.

Monday: The mid-levels will consist of zonal flow over our region.
At the surface, weak troughing should be located to our north, while
a cold front is over the spine of the Appalachians in the morning.
The cold front will quickly approach our area, possibly reaching our
inland zones by late in the day. A decent amount of moisture will be
across the region, ahead of the front. But models don`t point to
much shower activity. If anything, they indicate isolated showers
late in the afternoon with minimal QPF. Hence, the forecast has POPs
ranging from 10-20%. Temperatures warm up just ahead of the front
due to southwest surface winds and more sun than clouds. Highs
should reach around 80 degrees.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A cold front will move through our area Monday night, perhaps
bringing a brief period of isolated showers. High pressure should
then prevail Tuesday through Thursday, bringing dry weather. High
temperatures are expected to be near normal.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
KCHS/KJZI/KSAV: IFR fog and stratus will remain an issue through
at least 15Z...and potentially a little longer. But a gradual
improvement to MVFR will take shape late morning into early
afternoon, and eventually to VFR during the afternoon.
However, fog/stratus is looking to return again tonight and IFR
conditions appear likely at all terminals again from late
evening onward.

Extended Aviation Outlook: Brief flight restrictions are possible
due to showers Saturday into Sunday night.

&&

.MARINE...
Light winds and diminishing seas prevail today and much of
tonight. Northeasterly flow will begin to increase very late
tonight, although impacts will not occur until Saturday.

Meanwhile, some marine dense fog development is possible across
the nearshore waters today through tonight. Will monitor
conditions for potential marine Dense Fog Advisories.

Saturday: A weak cold front should be near our SC/GA border in the
morning. It`s forecasted to move south during the day, becoming
located south of our area during the evening and overnight hours,
while troughing develops just offshore. Additionally, High pressure
will pass to our north and northeast. This synoptic pattern will
cause the pressure gradient to steepen, leading to strong and gusty
NE winds and steep seas. Small Craft Advisories will be needed for
all of the ocean zones, and possibly the Charleston Harbor.

Sunday: A stationary front will be located just south of our area in
the morning, while troughing is just offshore. Additionally, High
pressure will be centered off the Northeast U.S. The High will
quickly shift further offshore. This will cause the front to quickly
lift north during the afternoon, becoming located north of our area
in the evening. NE to E winds in the morning are expected to ease
into the afternoon, while also clocking around to the S overnight.
The Small Craft Advisories within 20 nm should come to an end during
the afternoon. But the Small Craft Advisory for the GA waters beyond
20 nm should persist into the overnight because seas will take
longer to subside.

Monday and Beyond: A cold front will quickly approach our area from
the west and northwest during the day, moving through our area
overnight. It doesn`t appear that winds and/or seas will be high
enough to prompt Small Craft Advisories. High pressure should then
prevail Tuesday and Beyond.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Dense Fog Advisory until 10 AM EST this morning for GAZ087-088-
     099>101-116>119.
SC...Dense Fog Advisory until 10 AM EST this morning for SCZ040-
     042>045-047>052.
MARINE...None.

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...