392
FXUS62 KCHS 041110
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
710 AM EDT Tue Jun 4 2024

.SYNOPSIS...
High pressure will extend across the area through Wednesday. A
cold front will approach from the northwest on Thursday, then
slowly move through on Friday. High pressure returns for the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, shortwave ridging will slowly shift eastward with
a flattening of the flow ahead of an embedded shortwave moving
into the Southern Appalachians. At the surface, no change to the
pattern with high pressure still centered to the east over the
Atlantic driving southerly flow across the forecast area.
Precipitable water values will increase through the day,
starting off in the 1.4-1.6" range in the morning and rising to
around 2" across much of southeast Georgia by sunset. Model
soundings are again not particularly impressive, revealing
fairly warm mid-level temperatures that are limiting
instability. So while the decreased ridging and increased
moisture would support more convective activity, we are still
lacking the presence of any real triggering or focusing
mechanism. Therefore, the forecast still only features isolated
to scattered convection mostly impacting inland areas and
especially interior southeast Georgia. Model consensus features
convection mostly waiting until mid to late afternoon to
develop, and that is how the forecast has been timed as well.
Concerning the severe weather potential, the overall threat
remains low. Soundings suggest CAPE values on the order of
1,000-1,500 J/kg at most, with meager lapse rates and modest
DCAPE. Perhaps if a few storms can develop and throw out some
outflow boundaries there could be enough boundary interactions
to produce a stronger storm. Highs are forecast to be right
around 90 away from the immediate coast.

Tonight: Early evening convection should mostly favor inland
areas and steadily dissipate through the late evening hours. The
rest of the overnight is then expected to be dry. Lows are
forecast to be in the upper 60s inland and the low 70s along the
coast. Though there aren`t any significant fog concerns, some
guidance would suggest potential for shallow ground fog across
the far interior late in the period.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
A relatively active pattern is anticipated during the period. A
weak upper trough will persist with a series of shortwaves
rippling through. Fairly deep southerly flow will maintain a
moist airmass Wednesday and Thursday with PWATs around 1.85". A
sea breeze each afternoon will provide an additional focus for
convective development. The greatest convective coverage is
expected to be inland.

Friday, a cold front sags into the area, with deep westerly
flow developing during the day. Compression ahead of the front
is expected to produce a warm day with highs in the low to mid
90s. Drier air will move in during the morning. This, combined
with mid-level subsidence, should limit convective coverage.
However, given the cold front, we kept 20-30% PoPs, highest
farther to the south where better moisture will exist.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Although temps will remain fairly warm this weekend, the
airmass will noticeably change due to substantially lower
dewpoints. This should also limit the potential for convection.
An increase in moisture early next week and some shortwave
energy will bring a return to scattered diurnal convection.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 12z Wednesday. The best chance for afternoon and
evening showers and thunderstorms looks like it will be near
KSAV. However, we still expect that most activity will remain
well inland of the terminal and for now have opted to not
include any mention of convection.

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

&&

.MARINE...
Today and tonight: Southerly flow in the morning will turn a
bit more southeasterly in the afternoon and evening. Overall,
speeds are expected to be in the 10-15 knot range with gust up
to around 20 knots possible along the land/sea interface with
the development of the afternoon sea breeze. Seas are expected
to average 2-3 feet through the period.

Wednesday through Sunday: High pressure will remain over the
western Atlantic Wednesday 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, with winds turning W over the weekend.

&&

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