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671
FXUS62 KCHS 241915
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
315 PM EDT Mon Jun 24 2024

.SYNOPSIS...
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High pressure will remain over the western Atlantic while a weak
cold front approaches the area. This front will likely linger
near the area through mid-week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Convection has been very slow to develop today. The last few
runs of the WoFS since the initial 24/17z run have been
trending drier with each run. Pops through the remainder of the
afternoon have been lowered to 20-30% as a result. Dewpoints
are finally showing signs of mixing out inland, but are holding
well into the 70s across the coastal corridor. Heat indices have
been as high as 108-113 based on the more reliable observation
sites (with RAP dewpoint confirmation), mainly just inland from
the coast where dewpoints are running in the mid-upper 70s. The
current Heat Advisory through 6 PM looks on track. Heat indices
may surge a bit farther inland as the sea breeze moves inland,
but any 108+ values should hold in the current advisory area.
There may also be an isolated 113+, but any such instances look
to remain fairly isolated and not enough for an upgrade to an
Excessive Heat Warning.

Later this evening, the tail end of convection moving across
the Pee Dee could interact with the inland moving sea breeze to
spark off additional showers/tstms. There is a modest signal
showing this cluster impacting areas roughly along/north of the
I-26 corridor. Pops as high as 40-50% were highlighted in this
area with 20-30% elsewhere. An isolated strong/severe tstm could
occur with elevated DCAPE in place. Once convection moves
offshore and/or dissipates, expect a warm/humid night with lows
from the lower-mid 70s well inland to the lower 80s at the
beaches and Downtown Charleston.
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&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
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Broad troughing will persist across the East Coast on Tuesday,
gradually shifting to zonal flow on Wednesday and a return to
broad troughing Thursday. At the surface a weak cold front will
likely linger in the vicinity of the forecast area through
midweek. 850 hPa temperature anomalies will remain rather warm
through the period, which combined with little mixing each day,
will yield hot and humid conditions. Heat index values are
forecast to reach 102-107F inland. A few spots may make a run at
108F along the coastal counties, however coverage of these
values is not enough to warrant Heat Advisories at this
juncture. Each afternoon isolated to scattered showers and
thunderstorms will be possible, as PWATs remain elevated with
the front in the vicinity. PWAT values are forecast to remain
near 1.6-1.8", which is slightly above normal for this time of
year. CAPE values are forecast to reach around 1500 J/kg, with
model soundings indicating >1000 J/kg of DCAPE. A strong to
marginally severe thunderstorm cannot be ruled out any
afternoon, with strong wind gusts as the main hazard.
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&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
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An anticyclone aloft will be positioned over the southern U.S.
and will slowly shift eastward over the southeastern states
through the weekend. At the surface high pressure will extend
into the forecast area from the east with the center of high
pressure centered over Bermuda. Hot and humid conditions will
likely persist into the weekend. Head index values are forecast
to reach from around 103- 105F inland with values approaching
108F along the coastline. Head Advisories may be required. A
summertime pattern is expected through the period, with the
highest precipitation chances in the afternoon hours.
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&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
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24/18z TAF Discussion:
KCHS/KJZI/KSAV: Best chances for tstm impacts this afternoon
will be at KSAV and possibly a far north as KJZI. VCTS will be
highlighted at both terminals from roughly 19-21z with a TEMPO
for MVFR conditions in TSRA at the same time at KSAV. Risk for
showers/tstms could increase at KCHS by mid-evening as some
interaction with an approaching surface trough and inland moving
sea breeze occurs. VCSH was highlighted 02-05z for now to
trend. Otherwise, VFR through the period.

Extended Aviation Outlook: Brief flight restrictions will be
possible at all terminals with afternoon showers and
thunderstorms.
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&&

.MARINE...
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Tonight: South to southwest winds 15-20 kt will dominate the
waters tonight. There may be a few gusts to 25 kt, but durations
do not look long enough to support a Small Craft Advisory at
this time. Seas will average 3-5 ft.

Tuesday through Friday: Generally tranquil marine conditions
are expected through the period. Winds will gradually back each
day and veer overnight, strongest along the coastline as the
afternoon sea breeze/overnight land breeze develops. Seas should
average 2 to 3 ft.
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&&

.CLIMATE...
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The low temperature at KCHS so far today is 80. If this holds,
this will break the previous record high minimum of 79 set back
2016.
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&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory until 6 PM EDT this evening for GAZ117-119-139-
     141.
SC...Heat Advisory until 6 PM EDT this evening for SCZ048>051.
MARINE...None.

&&

$$