802
FXUS62 KCHS 030518
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
118 AM EDT Mon Jun 3 2024

.SYNOPSIS...
High pressure will extend across the area through Wednesday. A
cold front will slowly move through on Friday, followed by high
pressure.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Early this morning: No changes needed to the forecast through
sunrise. We are expected to remain dry through the rest of the
overnight thanks to the lack of any real triggering mechanism
for showers or thunderstorms. There are no fog concerns and lows
should mostly fall into the mid to upper 60s away from the
immediate coast.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
Monday: Weak ridging will be situated aloft, with a subtle
short wave to pass near the Santee River in the afternoon. At
the surface, high pressure is the main feature, although there
might be the development of a weak lee side trough. There isn`t
as much of a cap per sounding data, so we will be able to some
convection across the region. Lapse rates are only so-so, and
MUCAPE is forecast to reach 1000-1500 J/kg. But given the sea
breeze becoming more active, and upstream convection due to
diurnal heating and the lee trough will produce scattered
showers and t-storms. The greatest chances (50% PoPs) are near
and west of I-95 in the afternoon when buoyancy is the best.
Since DCAPE is in excess of 1000 J/kg and sounding do show an
inverted-V trace, there would be a risk for some strong wind
gusts where boundary interactions occur. Thus the severe risk is
non-zero. The HREF does show a 50% potential for more than 1
inch of rain late in the afternoon near and west of I-95. But
other guidance has much less probabilities of that happening.
850 mb temperatures reach 15-16C, and will support max
temperatures prior to convection hitting the mid and upper 80s.
Evening convection quickly diminishes far inland, and the rest
of Monday night looks to be rainfree. Although winds do
decouple, a south-southwest synoptic flow and higher dew points
will limit lows to just 66-70F inland, several degrees warmer at
and closer to the coast.

Tuesday: Ridging prevails aloft and the capping is better than
on Monday. As a result we hold PoPs down to just 20/30%, driven
mainly by the sea breeze and any mesoscale boundary
interactions. DCAPE is again favorable for strong wind gusts in
a few storms, but given poor lapse rates, the potential is less
than on Monday. 850 mb temperatures climb about another 1C,
leading to highs making it to the upper 80s and near 90F.

Wednesday: Surface ridging is a bit weaker, while aloft the
flow becomes more zonal. There is also a short wave that is
progged to move through, and with greater MUCAPE and slightly
better lapse rates, this will lead to a higher chance of
convection, as we show up to 50% probabilities. Temperatures
aren`t much different than Tuesday, with the slightly higher 850
mb temperatures negated by the higher rain chances.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
An anomalous upper low digs through the Great Lakes region
Thursday and Friday, then into the Northeast and Mid-Atlantic
vicinity during the weekend. That upper air pattern will likely
send a cold front toward us late in the week, with model
consensus showing that the cold front does indeed make it
through for the weekend. That`s difficult to do this time of
year, but guidance has been consistent on that happening, so we
maintain that forecast. There is a decent short wave that passes
through Thursday, leading to at least scattered coverage, then
less activity with the approaching front Friday due to better
capping, and then little to no chance for Saturday and Sunday if
there actually is the passage of the cold front prior to then.
Every day will be well above climo, mainly in the lower to
perhaps mid 90s, the combination of warm advection and
compressional heating in advance of the cold front, the due to
an offshore flow in its wake. Some heat indices will be near or
above 100F Thursday and Friday, but not enough for any Heat
Advisories.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 06z
Tuesday. Current thinking is that the best chance for showers
and thunderstorms will be inland of the terminals in the
afternoon and early evening hours. Therefore, we have not
included any mention in the TAF`s at this point.

Extended Aviation Outlook: Outside of any convection,
conditions will be VFR through the period.

&&

.MARINE...
Tonight: SE to SSE flow will prevail across the local waters,
with speeds mostly in the 10-15 knot range. The strongest winds
will likely be along the land/sea interface through early
evening and gusts up to around 20 knots will be possible. Seas
will average 2-3 feet.

Monday through Friday night: High pressure is the main weather
feature through the week, until a cold front approaches late in
the period. Winds will be mainly S or SW at 15 kt or less the
entire time, with seas no more than 2 or 3 feet. Of course in
any convection the winds and seas can be briefly higher. We`re
into the early part of our local waterspout season, so this will
be something that we`ll need to starting watching for.

&&

.TIDES/COASTAL FLOODING...
Due to tides running as much as 0.3 to 0.5 ft MLLW above
predicted astro tide levels, and increasing astronomical
influences, there is the risk for minor coastal flooding
starting Monday evening. The risk is greatest over coastal
sections of Charleston and Colleton County through the week. The
latest tide forecast for Charleston Harbor shows 7.0 ft MLLW
Monday evening, 7.1 ft MLLW Tuesday evening, and 7.3 ft MLLW
Wednesday evening. As a result, Coastal Flood Advisories are
likely. The highest during that time at Fort Pulaski is 9.3 ft
MLLW Wednesday evening.

&&

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

&&

$$

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