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514
FXUS62 KCHS 111301
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
901 AM EDT Sat May 11 2024

.SYNOPSIS...
High pressure will prevail through the weekend into early next
week. A storm system could affect the area by the middle of
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
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No major changes are planned for the late morning update.
Observed and model soundings suggest dewpoints will mix out a
bit more than expected, so hourly dewpoints were nudged down a
bit. Otherwise, the forecast is on track.

Today: Aloft, a northwest flow will dominate between a flat
ridge across the southern Gulf of Mexico and a mid-upper low
centered across the Great Lakes. At the sfc, a cold front will
shift further south of the local area, allowing dry high
pressure to build in its wake across southeast South Carolina
and southeast Georgia. The pattern will favor dry and slightly
cooler conditions than the previous dry with weak cold air
advection occurring early morning. However, cold air advection
will wane as the northwest flow takes shape across the Southeast,
resulting in a dry downsloping wind and perhaps some pinning of
the seabreeze closer to the coast locally into the afternoon.
High temps should peak in the upper 70s to around 80 degrees,
warmest along the I-95 corridor.

Tonight: Very little changes in regards to the pattern aloft. The
northwest flow aloft will maintain dry conditions through the night.
Clear skies and a weak pressure gradient should favor a decent
amount of radiational cooling while winds become light/calm away
from the coast during the first half of the night. However, a slight
uptick in winds could return late with the approach of a dry front
after midnight. Low temps should range in the mid 50s inland to low-
mid 60s near the coast.
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&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
Sunday: Broad troughing will persist across the East Coast,
resulting in northwesterly flow aloft over the local forecast area.
Surface high pressure centered over the Deep South will prevail. A
dry forecast has been maintained as downsloping flow aloft will
yield PWATs <1". Temperatures are forecast to be right around
normal, with highs in the low to mid 80s and overnight lows in the
upper 50s far inland to mid to upper 60s closer to the coast.

Monday and Tuesday: The synoptic pattern is expected to change on
Monday as a shortwave trough ripples across the southeastern states
ahead of a broad mid-level trough approaching from the Midwest. At
the surface the high pressure is forecast to shift offshore on
Monday as a warm front develops to the south of the forecast area.
Moisture will begin to pool in the forecast area ahead of the
approaching warm front, which combined with the forcing aloft from
the passing shortwave could spur isolated to scattered showers and
thunderstorms Monday afternoon. Instability is not impressive Monday
afternoon, so the risk of strong thunderstorms is almost zero. Have
included mention of thunder in the forecast as the ECMWF is showing
several hundred J/kg of CAPE, which could be enough to spawn a
grumble of thunder. Monday night into Tuesday the aforementioned
warm front is forecast to lift northward through the forecast area.
PWATs are forecast to surge to around 1.8", which would exceed the
daily maximum according to the SPC climatology. Numerous to
widespread showers and thunderstorms are forecast to move through
the region as several shortwaves ripple across aloft. It is worth
noting that some models hint at convection forming along the Florida
Panhandle. If this comes to fruition it could decrease the
precipitation coverage over the local forecast area. Model trends
will need to be monitored closely approaching Monday night and
Tuesday. Convective parameters are much more favorable on Tuesday,
with ML CAPE values forecast to reach anywhere from 800 to 1200 J/kg
as well as shear values 30-40 knots. A strong thunderstorm cannot be
ruled out. Temperatures Monday night are forecast to be rather mild,
only dipping into the upper 60s along the coastline, with mid 60s
further inland. Thick cloud cover on Tuesday could limit high
temperatures to only the upper 70s to low 80s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Aloft, a mid-level trough is forecast to push off the East Coast mid-
week, with another mid-level trough approaching at the end of the
week. At the surface a cold front is forecast to push through mid-
week, with another warm front impacting the region late in the week.
Isolated to scattered showers and thunderstorms will be possible
Wednesday and Thursday afternoons, with greater coverage possible on
Friday. Temperatures are expected to be above normal through the
period.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 12Z
Sunday.

Extended Aviation Outlook: VFR conditions will prevail through the
weekend. Showers and thunderstorms could bring flight restrictions
to the terminals Monday afternoon into the middle of next week.

&&

.MARINE...
Today and Tonight: A bit of surging should persist behind a departing
cold front to the south into early morning hours, favoring northerly
wind gusts around 20 kt. However, cold air advection post fropa
is expected to weaken late morning and afternoon with the arrival
of sfc high pressure and a northwest flow aloft. Sfc winds should
therefore decrease to around 10 kt while veering more northeast
late morning, then become southeast by late afternoon. An uptick
in winds is then expected during the night, especially after
midnight as a dry front passes near or just north of local waters
late. Southwest to west winds could increase to 10-15 kt. Seas
should generally range between 2-4 ft today, slowly subsiding to
1-2 ft overnight.

Sunday through Thursday: Generally tranquil marine conditions are
forecast through the end of the weekend as high pressure extends
over the local forecast area. Winds will generally be around 10
knots, with seas averaging 1 to 2 feet. Monday night S to SE winds
will surge slightly as a warm front lifts northward through the
region, generally around 15 knots with some gusts around 20 knots.
Seas will also increase, averaging 3 to 4 feet across the nearshore
waters, with 4 to 6 ft across the 20-60 nm offshore GA waters. A
Small Craft Advisory may be required. These conditions will persist
into the middle of the week.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$