534
FXUS62 KCHS 012003
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
403 PM EDT Sat Jun 1 2024

.SYNOPSIS...
High pressure will extend across the area through early this
upcoming week. A cold front could approach late in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Afternoon composite analysis reveals sharp short-wave ridging
across the Carolinas into the Atlantic waters and attending
surface high pressure centered over the mid Atlantic. Short-
wave trough axis is close behind, stretching down through the
Gulf Coast states. Corridor of precipitation ahead of the
trough has decayed substantially over the last several hours
while core of a convective complex is diving into the eastern
Gulf region. But we are getting higher cloud cover (convective
blow off) streaming into the region, along with a smattering of
heating of the day Cu development.

Tonight: Short-wave ridge axis and attending surface high
pressure center will be slipping off the Atlantic coast while
low amplitude troughiness slowly develops across the southeast
and axis of higher PWAT/dewpoint air nudges into the region
(PWAT values climb to >1 inch by 12Z Sunday). Given modest warm
advection forcing and larger scale QG-Forcing for ascent ahead
of the trough edging into the region, there may be some shower
activity to our west that tries to sneak into the far western
part of the forecast area overnight. In addition, high-res
guidance has also been hinting at showers kicking off in the
Atlantic coastal waters that try to make a run toward the coast
overnight. Precip probabilities are not zero, especially along
the coast. But given the low probs, we are maintaining the dry
forecast with this forecast cycle.

Given increasing cloud cover and dewpoints, overnight lows will
not be as cool as the last few nights with lows spanning the
60s...possibly some upper 50s in the normally cold spots.
Upper 60s to low 70s along the coast.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Sunday: Even though we`re under the influence of high pressure,
there is a short wave that moves through aloft. That along with
increasing moisture courtesy of a southerly low level flow, e might
actually get rain in some places. However, since MLCAPE isn`t overly
impressive, there isn`t much deep layer shear, and condensation
pressure deficits are around 100 mb, we aren`t inclined to show
anything more than slight chance/chance PoPs. Max temperatures were
derived from the MOS, NBM and NBM50Pct, equating to highs mainly in
the middle 80s away from the coast.

Sunday night: Withe the passage of the short wave, NVA develops, and
with nocturnal influences any early convection far inland on the
sea breeze will come to an end. Some of the guidance suggests that
marine activity could attempt to make a run for some coastal
sections of South carolina where the low level convergence is the
best. However, other guidance keeps any convection offshore, which
is where we leaned toward at this point. Within a southerly synoptic
flow our low temperatures won`t be as cool as recent nights.

Monday: Surface high pressure is still in control, with maybe some
weak lee side troughing forming. Another short wave might approach
late, and that along with additional moisture will promote at least
some convection. But once again, the MLCAPE and deep layered shear
are rather weak, and condensation pressure deficits are once again
close to 100 mb, so nothing more than slight chance/chance PoPs.
Something to watch for would be the DCAPE values, which are
potentially near 1000 J/kg due to dry air above 700 mb. This could
lead to some strong wind risk in the taller t-storms, and where
boundary interactions occur. Low level thickness and model consensus
supports highs in the upper 80s to perhaps 90F inland from the
beaches.

Tuesday: Ridging develops aloft, so the associated subsidence will
prevent much convection from developing. There is more MLCAPE
available, and with the sea breeze and the lee trough nearby, we
still show isolated PoPs, mainly inland. Utilizing a mixture of the
MOS and NBM guidance with 850 mb temperatures and the low level
thickness, we arrive at highs a bit warmer than on Monday, and many
places will reach 90F or greater. And with that comes some higher
dew points over the coastal corridor.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Flat riding or quasi-zonal flow will prevail aloft through Thursday,
before a deep upper low develops near the Great Lakes late in the
week. We`ll still be south of the associated trough, but this
pattern will force a cold front to likely approach late in the week.
For now we don`t have anything more than 20/30 PoPs, especially
since it`s difficult to get cold fronts into our neighborhood this
time of year. We feel more confidence on hotter conditions as 850 mb
temperatures that reach 17-18C Wednesday, are as high as 19-20C by
Friday. Max temperatures are look to be in the 90-95F range through
the period, provided the cold front doesn`t get this far southeast.
Associated heat indices Thursday and Friday could be near 100F in
many areas.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 18z
Sunday.

Extended Aviation Outlook: Conditions will generally be VFR through
the period.

&&

.MARINE...
Tonight: Surface high pressure over the mid Atlantic will slip
into the Atlantic tonight with northeasterly/easterly flow
currently across the coastal waters veering southeasterly
tonight. A touch of gustiness (gusts up to 20 knots) out there
this afternoon will diminish tonight with speeds largely 10 to
15 knots. Seas will run 2 to 4 feet, highest in the Georgia
outer waters.

Sunday through Thursday night: No real marine concerns outside of
any convection, with high pressure generally in control. Even with
afternoon/evening sea breeze influences, and nocturnal low level
jetting, winds will mainly be 15 kt or less, with seas no more than
3 or 4 feet.

Rip Currents: There were numerous reports of rip currents at Tybee
Beach earlier today, mainly due to the strong long shore current
reported by the lifeguards. Sunday could be similar, but given the
lack of swells, and both the in-house Rip Current Calculator and Rip
Current MOS showing low risk for all beaches, that`s what we have at
this time.

&&

.COASTAL FLOODING/TIDES...Tides are running above predicted
levels, and with higher astronomical tides upcoming due to the
Perigee early Sunday, and the New Moon on Thursday, there could
be some minor coastal flooding issues, especially over coastal
Charleston and coastal Colleton County. The first high tide of
potential concern is the evening high tide Monday, but each
evening tide through mid to late week to again be an issue.

&&

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

&&

$$

NEAR TERM...Adam
AVIATION...Adam
MARINE...Adam