603
FXUS62 KCHS 031401
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1001 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 /THROUGH TONIGHT/...
Today: In wake of a short wave pulling further offshore, a weak
short wave ridge will prevail aloft. At the surface, the local
region lies under the western portion of the Bermuda-Azores
High, with some indications of a lee side trough developing
late. The overall environment is not especially favorable for
convection given weak lapse rates, only 1000 J/kg to maybe 1500
J/kg of MLCAPE, a TTI of 45 at best, and a 3-4C cap that needs
to be overcome. However, guidance is not doing a good job of the
convection in the Central Savannah River Valley region to parts
of the South Carolina Upstate. This seems to be generated by a
subtle impulse aloft, that should weaken as it trends further
east. That activity though will likely leave a boundary for
afternoon development. Even so, other than that, the sea breeze
and daytime heating, there isn`t expected to be more than
scattered coverage. The greatest chances are inland where
boundary interactions will transpire. One item of note is the
DCAPE which will peak around 1000-1200 J/kg. Given the lack of
any substantial strength to the updrafts, this wouldn`t be able
to produce anything more than some gusty winds in a few
t-storms. Both the 00Z and 06Z HREF have backed off on the risk
of any heavy rain concerns near and west of I-95 like it showed
from yesterday. Our 850 mb temperatures are 2C warmer than
yesterday, and that along with temperatures running several
degrees warmer than 24 hours ago will produce highs well into
the 80s away from the immediate coast.

Tonight: Any ongoing convection should quickly end during the
early evening hours with the loss of diurnal heating. The rest
of the overnight will be quiet and dry, with no notable fog
concerns. Lows are forecast to fall into the mid to upper 60s
away from the immediate coast.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
A potent shortwave is forecast to move in from the west Tuesday
afternoon. PWATs above 1.8" and moderate instability should be
in place during the afternoon. Meanwhile, the seabreeze will
eventually shift inland later in the afternoon. Decent
convective coverage expected farther inland in the afternoon,
with more isolated activity closer to the coast.

Slightly higher surface dewpoints on Wednesday are expected to
result in considerably greater instability. Southerly prevailing
flow should allow for a more progressive sea breeze in the
afternoon. A few weak vort maxima expected to move through
during the day. Scattered convection expected mainly during the
daytime. Model DCAPE values exceed 1000 J/kg over inland areas
so we could see some gusty winds in some storms.

Thursday could be the most active day this week due to upper
levels transitioning to a broad upper trough and a pronounced
shortwave moving through in the afternoon. PWATs expected to
rise to near 2" during the day, providing plenty of moisture for
showers and thunderstorms to develop.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A cold front drops through the area on Friday, however
convective coverage is uncertain since mid-level subsidence
seems likely given the quasi-zonal flow. Compressional heating
looks to push highs into the low to mid 90s.

A noticeable airmass change is expected this weekend as high
pressure builds from the northwest. Downslope flow should still
keep highs above 90 in most spots, but dewpoints should mix down
into the upper 50s to lower 60s.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 12z
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...
Today and tonight: High pressure to the east will remain the
primary feature controlling winds and seas across the local
waters. Winds are expected to be southerly to south-
southeasterly through the period with speeds topping out in the
10-15 knot range. Some enhancement along the land/sea interface
can be expected in the afternoon and early evening thanks to the
sea breeze. Seas are expected to average 2-3 feet.

Tuesday through Saturday: High pressure will remain over the
western Atlantic Tuesday through Thursday night, maintaining
southerly flow at or below 15 kt, seas at or below 4 ft, and a
daily sea breeze circulation along the coast. A cold front will
move through on Friday, briefly shifting winds to the NW before
they turn back E by Saturday.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides are on the rise this week. Although wind
direction is not particularly favorable for surge, we continue
to see a positive tidal anomaly of 0.5 to 0.7 ft. The evening
high tides Tuesday through Thursday could reach at least 7.0 ft
MLLW in Charleston, necessitating Coastal Flood Advisories.

&&

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

&&

$$

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