865
FXUS62 KCHS 221559
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1059 AM EST Fri Nov 22 2024

.SYNOPSIS...
Canadian high pressure will remain the primary feature through
early next week. A cold front could approach the area towards
the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, a large mid-upper lvl low centered across the
Northeast United States will meander near the Northeast Coast with a
trough axis extending across the Southeast and offshore. At the sfc,
high pressure will prevail throughout the day. The setup will favor
cold air advection and dry weather conditions across the local area
with another breezy day anticipated late morning and afternoon. In
general, westerly winds between 10-15 mph with gusts to 20-25 mph
will be common. Skies will also remain clear allowing for ample
sunshine, but cold air advection will offset substantial sfc heating
and limit highs generally to the mid-upper 50s.

Tonight: By the evening, winds should decouple after sunset and
allow for decent radiational cooling overnight bringing lows
down to the mid to upper 30s. Conditions should be more
supportive of patchy frost tonight compared to the night before,
however a Frost Advisory does not look likely at this time.

Lake Winds: Winds over Lake Moultrie have diminished quite a
bit overnight. They are expected to pick back up after sunrise
with speeds of 15 to 20 kt and gusts to around 25 kt. However,
by the evening they should relax back down to 10 to 15 kt with
gust up to 20 kt. A Lake Wind Advisory has been extended through
noon to see how wind gusts go through the morning and determine
if the advisory needs to be extended further into the
afternoon.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Long wave trough axis will ripple east over the Atlantic on
Saturday. Mid-level flow across the forecast area will become
generally zonal flow on Sunday, tilting slightly from SW to NE
on Monday. On Saturday, the center of surface high pressure
should remain centered over Deep South, resulting in light WNW
winds across the forecast area. Using a blend of MOS, high
temperatures with sunny conditions should favor values in the
low 60s, 5 to 7 degrees below normal.

Saturday night, the center of sfc high pressure is forecast to
slide over the FL/GA line. After sunset, winds should become
light to calm across the forecast area. The combination of clear
sky with little to no wind should provide several hours of
excellent radiational cooling conditions. Dewpoints should
gradually narrow through the night, with most areas reaching the
upper 90s RH during the pre-dawn hours. Low temperatures should
range in the mid 30s, with a few spots reaching freezing across
portions of the inland counties. It appears that areas of frost
will develop inland late Saturday night into early Sunday
morning. Elsewhere, scattered frost is possible, especially just
inland of the coastal counties. The frost potential will remain
highlighted in the Hazardous Weather Outlook.

Sunday through Monday, the forecast area is expected to remain
between high pressure over the western Atlantic as a cold front
across the middle CONUS. This pattern will provide the region
with steady return flow and rising LLVL thicknesses.
Temperatures should return to normal on Sunday, with highs in
the upper 60s. On Monday, temperatures will continue to
moderate, with highs on Monday reaching the low to mid 70s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Medium range guidance indicates that a cold front is timed to
approach the CWA from west Monday night, then pushing across on
Tuesday. The front is expected to bring a band of SCT to BKN
cloud cover across the region. Temperatures ahead of the front
should remain well above normal, high Tuesday ranging in the mid
to upper 70s.

Wednesday, high pressure should slide across the region in the
wake of the cold front. Conditions should remain dry with
temperatures near normal.

GFS and ECMWF indicate that broad longwave trough will amplify
over the Southern Plains Wednesday night into Thanksgiving. This
disturbance will ripple across the region during the daylight
hours Thanksgiving into Friday. During this period, the forecast
will feature SCHC PoPs for light showers. Temperatures should
remain mild, with the warmest values expected Thanksgiving
afternoon in the mid to upper 70s.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 12z
Saturday. Breezy northwest winds are expected again today, with
frequent gusts at all 3 sites up to around 25 knots at times.

Extended Aviation Outlook: VFR.

&&

.MARINE...
Today and Tonight: Westerly winds will persist at 20-25 kt with
gusts to 30 kt over the waters with 15-20 kt with gusts to 25 kt
in the Charleston Harbor. Seas will range 3 to 5 ft across much
of the waters except for the outer coastal waters reaching to
6-7 ft. For the Charleston Harbor, gusts should fall below 25 kt
this evening so the Advisory is scheduled to come down at 23z/6 PM.
Small Craft Advisories remain in effect for all waters through
tonight.

Saturday through Wednesday: High pressure will remain across
the coastal waters this weekend into earl next week, then a weak
cold front is timed to push across the region on Tuesday. Winds
through the period should favor values of 10 kts or less. Seas
are forecast to range between 1-2 ft.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until noon EST today for SCZ045.
MARINE...Small Craft Advisory until 6 PM EST this evening for AMZ330.
     Small Craft Advisory until 7 AM EST Saturday for AMZ350-352-
     354.
     Small Craft Advisory until 10 AM EST Saturday for AMZ374.

&&

$$

NEAR TERM...DPB
SHORT TERM...NED
LONG TERM...NED
AVIATION...BSH/NED
MARINE...DPB/NED