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000
FXUS62 KCHS 161711
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
111 PM EDT Tue Apr 16 2024

.SYNOPSIS...
High pressure will persist through the end of the work week. A
cold front is forecasted to impact our area this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early this afternoon: No change to the forecast. Previous
discussion continues below.

Late this morning: All quiet across the forecast area. Ridging
aloft and high pressure at the surface will result in a dry
forecast with seasonally warm temperatures. Dewpoints are
expected to mix out nicely, so it shouldn`t feel too bad despite
the expected high temperatures. Low-level thickness values are
slightly higher than 24 hours ago, so we expect to see highs
very similar to yesterday. Look for upper 80s away from the
immediate coast, with a few locations hitting 90. Another well
developed and progressive sea breeze is expected with water
temperatures still in the upper 60s.

Tonight: Another quiet night of weather conditions will prevail
with sfc high pressure extending from the western Atlantic and
the axis of a ridge directly positioned across the Southeast
aloft. The pressure gradient will remain weak, resulting in
light southerly winds during the night. Although some
radiational cooling is expected, a more substantial amount of
cirrus clouds across the local area will limit overall cooling.
Overnight lows should remain a few degrees warmer than the
previous night as a result, generally ranging in the lower 60s
inland to mid-upper 60s near the coast.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Wednesday: Mid-level ridging over the East Coast in the morning
will weaken as it slowly shifts offshore during the afternoon.
Following this will be zonal flow over our area during the
evening and overnight. Surface High pressure will be centered
west of Bermuda, shifting westward with time. It`s western
periphery will stretch into our region. Additionally, Low
pressure will be moving through the Great Lakes Region. An
attached warm front will remain well to the north of our area,
while a cold front approaches from the distant west. However,
this front is not expected to reach our area, mainly due to the
High pushing it away from us, just to the north. The High will
keep our area dry during the day. Synoptic models indicate a
band of weak showers associated with the cold front approaching
our area overnight. However, these showers are expected to
weaken/dissipate before they make it into our area. So while we
have POPs across our SC counties rising to ~10% overnight, no
measurable rainfall is expected. Southerly surface winds during
the day will be followed by an afternoon sea breeze quickly
moving inland. Despite partly to mostly cloudy skies, the
combination of warm 850 mb temperatures and low-level thickness
values support well above normal highs in the mid to upper 80s,
except cooler at the beaches. Lows will be mild, generally in
the 60s.

Thursday: The mid-levels will consist of zonal flow over our
region in the morning. Ridging will develop over the Southeast
U.S. in the afternoon, then strengthen along the entire East
Coast into the evening and overnight. This will yield rising
heights over our area. At the surface, a weak cold front will be
located to our northwest early in the morning. It`ll pass to
our north during the morning, then offshore in the afternoon,
all while weakening. Weak High pressure to our southeast will
then stretch into our region during the afternoon and evening.
Another front will approach from the distant west overnight.
Though, it won`t make it to our area during this time period.
Any non-zero POPs at daybreak will drop to zero during the
morning. The synoptic models generally keep our area dry through
the afternoon. POPs start to creep up in the evening and
overnight. But they only max out around 10%, so no measurable
rainfall is expected. SW surface winds during the day will be
followed by another afternoon sea breeze quickly moving inland.
Mostly cloudy skies in the morning will become partly cloudy in
the afternoon, then persist into the night. Once again, the
combination of warm 850 mb temperatures and low-level thickness
values support well above normal highs in the upper 80s to
around 90 degrees, except cooler at the beaches. Lows will
remain very mild, easily in the 60s.

Friday: Mid-level ridging over the East Coast in the morning
will shift offshore into the afternoon, leading to lowering
heights and the development of zonal flow over our area. Surface
High pressure located to our Southeast in the morning will move
away into the afternoon. Meanwhile, a cold front will approach
from the northwest. Moisture creeps higher ahead of the front,
with PWATs rising to ~1.5". Synoptic models indicate some
showers developing in the afternoon, partly ahead of the front
and partly associated with the afternoon sea breeze moving
inland. A few rumbles of thunder cannot be ruled out. While
clouds should gradually increase into the afternoon, again the
combination of warm 850 mb temperatures and low- level thickness
values support well above normal highs in the upper 80s to
lower 90s, except cooler at the beaches.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Mid-level zonal flow will prevail overhead into Saturday.
Troughing will start to develop over the Great Lakes Region on
Sunday, causing heights to lower over our area. This is followed
by large scale troughing starting to develop over the eastern
half of the U.S. on Monday. A front will approach our area
during the weekend, moving through early next week. There remain
distinct differences between the models. The GFS has unsettled
weather the entire weekend into early next week. The ECMWF has
it mostly dry the entire weekend, with Monday being wet. So we
continue to go with the blend until the models start to come
into better agreement. Temperatures will remain above normal
Saturday, then cool down next week.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 18z
Wednesday. Passage of the sea breeze this afternoon will bring
a few low end gusts of 15-18 knots beginning around 19-20z.

Extended Aviation Outlook: VFR through Friday. A front could
bring occasional flight restrictions in showers on Saturday.

&&

.MARINE...
Today and Tonight: High pressure will remain the dominant
weather feature locally, extending from the western Atlantic and
across the Southeast United States. Expect southwest winds
along the western periphery of the high with speeds up to 10-15
kt across most waters, turning south this afternoon as a
seabreeze develops and shifts inland. A few gusts around 20 kt
are possible along the coast as the seabreeze takes shape,
mainly along the Charleston County coast and across the
Charleston Harbor. Winds will become light overnight, remaining
around 10 kt or less by midnight. Seas will range between 2-3
ft.

High pressure will be stationary over or near Bermuda through
at least Thursday. It`s periphery will, drive our local winds.
Each morning expect backing winds, followed by gusty winds along
the land/sea interface in the afternoon due to the formation of
the sea breeze. Gusts should be around 20 kt in the Charleston
Harbor with its passage. Each evening, winds will veer and
increase as some coastal jetting develops overnight. Friday is
when a front will approach our area. It`s uncertain when the
front will move through our area, either during the weekend or
early next week. But when it does, winds and seas don`t appear
to be high enough to prompt Small Craft Advisories. Seas should
mostly be 2-3 ft.

&&

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

&&

$$

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