403
FXUS62 KCHS 060735
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
335 AM EDT Sat Jul 6 2024

.SYNOPSIS...
A weak front will remain stalled near the area through much of
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest 500 MB hand analysis revealed a 592 dam ridge centered near
the Panhandle of FL with a broad trough axis centered across the
central United States. On water vapor, an area of low pressure
in the mid-levels was noted in the western Atlantic retrograding
to the west. During the day today, the trough axis will
slightly nudge to the east with the mid-level low over the
Atlantic making progress to the west. As this occurs, the mid-
level ridge that was over the FL Panhandle will start to re-
center across central FL. Low level thicknesses today (1000/ 850
mb) reflect the new position of the ridge with a slight
decrease to 1430 m (compared to 1435 m on Friday). Given this,
have kept high temperatures mostly in the mid 90s today with
upper 80s forecast at area beaches. However, dewpoints will
remain in the mid to upper 70s with heat index values up to 110
degrees in places. As such, a heat advisory remains in effect
for portions of southeast GA and SC.

The main change for today compared to Friday will be the
dramatic increase in coverage of showers and thunderstorms.
PWATs will rise to above 2.5" across the western zones with
drier air remaining entrenched across Charleston and Berkeley
counties (PWATs around 1.7"). This makes sense as the dry air
from Friday is getting squeezed between and approaching
disturbance from the west and east. A very weak cold front will
also approach the Upstate of SC this afternoon with a lee side
trough again developing across the Midlands of SC. This setup
usually favors CI occurring across the Upstate first followed by
the Midlands. Along the coast of SC not much in the way of
coverage is expected with a tight gradient to likely PoPs in
Allendale county. West of I-95 in GA also should observe fairly
robust coverage with the weak trough and approaching front.
Isolated totals up to 3" will be possible as storm motion is
less than 5 kt (estimated by the mean cloud-bearing wind).
However, most locations that measure precipitation today will be
in the 1" to 2" range.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A weak upper ridge will remain over the Southeast during the
period, though weak disturbances will continuously move
through. Meanwhile, a weak front will remain stalled just
inland. The airmass will be particularly moist during the period
with PWATs generally at or above 2.1". Prevailing S to SE
surface flow will support a robust inland-moving sea breeze each
afternoon. There will be plenty of forcing and moisture to
support numerous showers and thunderstorms, particularly during
the afternoon and evening hours. The greatest coverage is
expected to be across the inland areas. Instability does not
look to be strong enough to warrant a significant severe
thunderstorm risk, though localized flooding is possible due to
heavy rainfall. The weakening upper ridge will bring some
slight relief from the heat, though mid to upper 70s dewpoints
will still push heat indices above 100F each day.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A relatively wet pattern is likely to persist into late next
week. Deep tropical moisture will remain in place while a series
of shortwaves ripple through. Meanwhile, a weak lee trough will
remain across the Midlands and a robust sea breeze will occur
each afternoon. Numerous showers and thunderstorms expected each
day, with potentially scattered coverage extending well into the
overnight hours. High temps will briefly rise into the mid 90s
by Wednesday, then back to the lower 90s late in the week. We
could flirt with Heat Advisory criteria just about any day,
though our forecast right now keeps most areas below 108 heat
index.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
KCHS/ KSAV: Terminals will remain VFR through most of the
issuance. Mid-level high pressure will begin to breakdown this
morning with upper level disturbances to the west and east. A
weak lee side trough (or convergence of surface winds) is again
forecast to take shape across the Midlands of South Carolina.
The best chance of showers and thunderstorms will likely be west
of KCHS/ KSAV, but these terminals appear far enough inland (at
least from current guidance) to maintain the mention of vicinity
thunder. Confidence is slightly lower at KCHS though, as
forecast soundings do show some dry air remaining in the profile
tomorrow afternoon (much less so at KSAV).

KJZI: VFR through the issuance expected. Mid-level high
pressure will begin to breakdown this morning with upper level
disturbances to the west and east. A weak lee side trough (or
convergence of surface winds) is again forecast to take shape
across the Midlands of South Carolina. Charleston Executive will
be to close to the coast Saturday with showers and
thunderstorms forming inland, or away from the terminal.
Therefore there is no mention of vicinity thunder.

Extended Aviation Outlook: Brief flight restrictions possible in
showers and thunderstorms, particularly during the afternoon and
early evening.

&&

.MARINE...
Saturday: Expect seas around 3 ft with southerly winds backing
from the southeast in the afternoon with a daytime sea breeze
developing. Winds will mainly be 15 kt or less.

Sunday through Thursday, a typical summertime pattern will
prevail. Southerly winds will typically be less than 15 knots
and seas no higher than 4 ft.

Rip Currents: A swell of 2 feet every 9 to 10 seconds and proximity
to the new moon will maintain a Moderate Risk for rip currents
for today (Saturday).

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ087-088-099>101-114>119-137>141.
SC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for SCZ040-042>045-047>052.
MARINE...None.

&&

$$

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