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000
FXUS62 KCHS 151330
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
930 AM EDT Mon Apr 15 2024

.SYNOPSIS...
High pressure will persist much of this week. A cold front
might impact our area during the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Ridging aloft over the Great Plains early on will shift
east toward the Mississippi Valley, allowing for rising heights
locally to occur. At the surface, a lee side trough will remain
further inland, while Bermuda high pressure stretches across
Florida and the northern Gulf of Mexico states. Although the
PWat is higher than recent days (0.79 inches from the 12Z CHS
sounding), it`s another day with strong subsidence and a deep
offshore flow. 850 mb temperatures up to 14-15C, the increase
in heights, and an expansion of the low level thickness, all
point toward a very warm day. Morning temperatures are already
about 6-10F warmer than 24 hours ago, which points toward highs
this afternoon topping out in the mid and upper 80s. The beaches
will be held into the 70s as a modest afternoon sea breeze
develops. Min RH`s will drop below 30% inland, maybe even as low
as 20-25% in a few places.

Tonight: Quiet weather conditions will prevail with sfc high pressure
extending from the western Atlantic and the axis of a ridge becoming
more directly positioned across the Southeast aloft. The pressure
gradient will remain weak and favorable radiational cooling will
take place while south/southwest winds become light/calm. In
general, low temps should range in the mid-upper 50s inland to low-
mid 60s near the coast.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: The mid-levels will consist of ridging just east of the MS
River Valley in the morning. The ridge will shift eastward, with its
axis becoming located over the East Coast overnight, leading to
rising heights over our area. At the surface, High pressure will be
centered over or near Bermuda, with it`s periphery stretching into
our region. This will keep a front well to the north of our area,
bringing us dry conditions. Skies will start out mostly sunny, with
cirrus increasing during the day, then increasing further during the
evening and overnight. SSW surface winds during the day will be
followed by an afternoon sea breeze quickly moving inland. 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.

Wednesday: Mid-level ridging over the East Coast in the morning will
weaken as it slowly shifts offshore during the afternoon, yielding
zonal flow over our area during the evening and overnight. Surface
High pressure will be centered west of Bermuda, with it`s periphery
still stretching 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 and to the
north. It should remain dry during the day. Synoptic models indicate
a band of showers associated with the cold front approaching our
area overnight. However, these showers should 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 mostly cloudy
skies, the combination of warm 850 mb temperatures and low-level
thickness values still support well above normal highs in the mid
80s, except cooler at the beaches. Lows will remain mild, generally
in the 60s.

Thursday: The mid-levels will consist of zonal flow over our region,
with signs of weak ridging trying to develop over the Southeast U.S.
in the afternoon, yielding rising heights. 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. Another front will approach from the
distant west. Though, it won`t make it to our area during this time
period. The synoptic models generally keep our area dry. SW surface
winds during the day will be followed by another afternoon sea
breeze quickly moving inland. Mostly cloudy skies in the morning
will gradually clear into the afternoon. Once again, the combination
of warm 850 mb temperatures and low-level thickness values support
well above normal highs in the upper 80s, except cooler at the
beaches.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
The mid-level ridge axis will shift further offshore Thursday night,
leading to zonal flow that`ll prevail overhead into Saturday.
Troughing will start to develop over the Great Lakes Region on
Sunday, causing heights to lower over our area. A front will
approach our area during the weekend. The long-term models still
disagree on whether the front will slowly move through our area this
weekend, or quickly move through early next week. For this reason,
we generally kept our forecast drier than what the models have, but
expect this portion of the forecast to change. Temperatures will
remain above normal into Saturday, then cool down early next week.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 12Z
Tuesday.

Extended Aviation Outlook: VFR.

&&

.MARINE...
Today and Tonight: High pressure will extend across western Atlantic
and local waters while a trough/front is positioned across the Mid-
Atlantic states. The pressure gradient will remain modestly enhanced
between these two features, supporting west-southwest winds upwards
to 10-15 kt this morning. Expect winds to gradually turn more south
this afternoon and potentially gust up to 20 kt near the coast as a
seabreeze develops and shifts inland, especially along the Charleston
County coast and across the Charleston Harbor. The pressure gradient
should then weaken during the overnight period, suggesting south-
southwest winds to remain at or below 10 kt. Seas will generally
range between 1-3 ft today, then gradually build to 2-4 ft during
the night.

Extended Marine: High pressure will become stationary over or near
Bermuda Monday through at least Thursday. It`s periphery will be the
dominant feature for our weather, driving 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. This pattern looks to remain in
place through Thursday. Friday is when a front could approach our
area. The front should move through our area sometime during the
weekend. No Small Craft Advisories are expected. Seas should mostly
be 2-3 ft within 20 nm and 2-4 ft for the GA waters beyond 20 nm.

&&

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

&&

$$

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