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137
FXUS62 KCHS 241135
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
735 AM EDT Fri May 24 2024

.SYNOPSIS...
A series of weak disturbances will move through the area late
week into the holiday weekend. A cold front could bring impacts
to the region Monday night into Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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No substantial changes were made to the forecast with the early
morning update. Quiet weather remains this morning with some
cloud cover drifting through. Upstream MCV appears to be moving
into western Georgia and still looking to assist in kicking off
convection this afternoon.

Previous discussion...
Overnight composite analysis reveals a bit more suppressed zonal
flow pattern across the southern CONUS over top upper level high
pressure across Mexico into the Gulf. A few clusters of showers and
thunderstorms are present across the Gulf Coast and mid Atlantic
regions while dry weather remains prevalent across the southeast
states. Pattern remains largely unchanged through tonight with zonal
flow persisting across the Deep South and convectively induced MCVs
traversing the region.

Today: Another very warm day is on tap with H8 temps warming
another degree or two compared to Thursday...suggesting highs in
the upper 80s to lower 90s away from the coast. But still well
away from record highs in the upper 90s for this date. Daytime
heating will drive MLCAPE values into the 1-2K J/Kg range and
likely a little higher along the inland pressing sea breeze with
less CINH/capping compared to recent days. Meanwhile, remnant
MCV from decaying convection along the Gulf Coast will be
rippling into the region during the afternoon hours in tandem
with a decent low level convergence signal along the sea breeze.
That should kick off a decent coverage of thunderstorms in the
region this afternoon into this evening with the best coverage
likely across the coastal counties. That said, successive high-
res guidance runs have shown mixed results in terms of coverage
and placement of convection this afternoon lending to a bit
lower forecast confidence. Even so, given the instability and
arriving MCV, we feel compelled to increase pops into at least
the likely range along the coast.

Severe storms: Plenty of instability this afternoon especially
along the sea breeze along with a fair amount of DCAPE and an
inverted V look to forecast soundings suggest some potential for
damaging wind gusts with the strongest storms. In addition,
PWAT values around 1.7 inches will support heavy rainfall
potential although storms should exhibit a fair E/SE storm
motion. Overall rainfall amounts of 0.5 to 1.0 inch seems
reasonable with localized 1.0 to 1.5 inches possible.

Tonight: Convection will wind down during the course of the
evening with loss of heating and exit of the MCV. But, another
MCV/ripple in the flow may be right behind potentially
bringing additional showers and thunderstorms into the area
late. Again, each successive high resolution guidance run offers
a differing scenario leading to low confidence. For now, we
have precip chances starting to increase again toward Saturday
morning.
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&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Northwest flow develops aloft on Saturday as a shortwave trough
shifts offshore. There could be some convective activity moving
through in the morning, with additional development expected in the
afternoon during peak heating. Shear remains around 20 knots, so an
organized severe threat is not expected, but a few stronger storms
with gusty winds are possible with drier air in the mid levels and
DCAPE progs approaching 1000 J/kg. Temperatures will peak around
90/lower 90s. Showers/thunderstorms should fade/shift offshore
Saturday evening. Lows mainly in the upper 60s to lower 70s.

Mid level heights continue to build overhead on Sunday. Convection
will be limited with mainly just isolated diurnal showers and
thunderstorms possible. The hot temperatures will continue with
highs forecast to reach the low to mid 90s (this is 5 to even 10
degrees above climo). Low temperatures stay mild, only falling to
the lower 70s.

The ridge axis will get pushed offshore on Monday/Memorial Day as a
mid level trough shifts into the eastern CONUS. Concurrently, a cold
front will approach the region. Convection could stay pretty
isolated through much of the daylight hours, before activity
possibly moves in from the west later in the day and overnight.
Forecast features just 20% rain chances through 00z. It will be
another hot day with highs again in the lower to mid 90s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A cold front moves into the region Monday night into Tuesday. There
should be an uptick in shower/thunderstorm coverage during this
timeframe with larger scale forcing for ascent. Quieter weather
looks to return mid week and beyond with deepest moisture exiting
off the coast. Unseasonably warm temperatures will moderate back to
normal through the period.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
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VFR conditions are expected at the CHS/JZI/SAV terminals
through at at least 18Z. Showers and/or thunderstorms may
eventually impact the terminals mid-late afternoon for a few
hours and produce flight restrictions. VCTS has been included at
all terminals from 20Z through 00Z/01Z. Convection diminishes
thereafter, although some additional convection might advance
back into the region late overnight. However, confidence is too
low to add any mention to the current terminal forecast.

Extended Aviation Outlook: Brief flight restrictions are possible
due to showers/thunderstorms each afternoon/evening.
-- End Changed Discussion --

&&

.MARINE...
Surface high pressure will remain off the southeast coast
through tonight with south to southwest winds prevalent. Wind
speeds of 10 to 15 knots will be common and seas 3 feet or less.

Saturday through Wednesday: Southerly flow prevails through early
next week, until a cold front cross the waters late in the period.
Conditions stay below Small Craft Advisory criteria, with winds
generally 15 knots or less and seas 2-3 feet on average.

&&

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

&&

$$