342
FXUS62 KCHS 021341
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
941 AM EDT Tue Jul 2 2024

.SYNOPSIS...
A stalled front will linger near the area today before
dissipating offshore. A hot and humid air mass will build over
the region during the latter half of the week. A weak cold
front could approach the region by Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Impressive pockets of heavy rainfall have been observed
along the Georgia coast this morning with some spots picking up
nearly 5 inches of rain. Showers and tstms will linger in this
area this morning before slowly waning through the afternoon. A
risk for locally heavy rainfall will persist areas along/south
of I-16 through early afternoon with the greatest focus centered
along the Georgia coast. Consideration was made to hoist a
Flood Watch for the Georgia coast, but considering the heaviest
rains should fall along the mostly unpopulated eastern areas of
McIntosh, Liberty and Bryan Counties, the decision was made to
hold steady. The only exception could be across eastern Chatham
County, including parts of Savannah Metro, where more impacts
should be realized if heavy rains develop. NWS Staff are
coordinating closely with Chatham County Emergency Management
(CEMA). Near term pops were adjusted slightly to reflect current
trends. Thunder was removed across the far interior where
instability will remain limited. Highs were also nudged down in
most areas with a rather cool day for July expected, especially
over the Charleston Tri-County area.

Tonight: Latest guidance has trended a bit more toward holding onto
precip activity south of the front across southeast Georgia.
However, diurnal heat loss should result in most convection to wane
during evening hours. Additional showers and thunderstorms could
redevelop across coastal waters and make a run toward the coast
late. At this time, scattered showers and thunderstorms remain in
the forecast across coastal areas through much of the night to
account for this possibility. Low temps should range between the low-
mid 70s inland to upper 70s near the beaches.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
High pressure off the mid-Atlantic coast will extend across the area
on Wednesday, while a stalled front lingering nearby eventually
dissipates. Aloft, a mid level ridge will build over the Southeast.
Best potential for convection will be near the southern South
Carolina coast and across southeast Georgia where deepest moisture
resides. Further inland and to the north should not see as much
activity. Highs will be in the upper 80s to lower 90s. Lows
Wednesday night will range from around 70 inland to upper 70s at the
beaches.

Mid level ridge will dominate the pattern aloft Thursday and Friday.
The surface will feature high pressure offshore and a trough of low
pressure inland. Mainly just isolated to perhaps scattered diurnally-
driven showers and thunderstorms are expected each afternoon and
evening. Otherwise, temperatures and humidity will be on the rise.
Highs will be in the low to mid 90s on Thursday, with heat indices
topping out in the 100-105 range. Friday will be a bit hotter, and
heat indices could approach local Heat Advisory criteria of 108
degrees in spots. Lows will be in the 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Guidance is in good agreement in the extended. Mid level ridge will
hold over Southeast coast into the weekend, before weakening. At the
surface, a trough of low pressure will persist inland with high
pressure offshore. It should get a bit more convectively active than
previous days with better instability and possibly weak upper
support. Current forecast highlights chance PoPs (generally 40-50%)
each day with coverage peaking in the afternoon and evening. We are
continuing to monitor the potential for excessive heat. Highs temps
mainly in the mid to perhaps upper 90s combined with elevated dew
points will make it feel even hotter. Heat indices are forecast to
approach or exceed 108 in many locations, with some potential to
even hit 113. Excessive heat headlines could eventually be needed.
Convection could disrupt temperature trends.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
KCHS/KJZI: IFR cigs are possible during the next few hours before
gradually improving to MVFR mid-late morning and persisting into
early afternoon. Should a few showers redevelop across northern
areas today, tempo groups of low-end MVFR or even IFR could return.
Otherwise, conditions should improve to this afternoon, then prevail
through 12Z Wednesday.

KSAV: Prevailing IFR cigs will continue for the next few hours
before attempting to improve to MVFR later this morning. However,
moderate to heavy showers (and potentially thunderstorms) should
impact the terminal by mid morning, bringing periods of IFR or even
lower conditions through late morning and potentially into early
afternoon. Otherwise, conditions should slowly improve mid-late
afternoon to VFR and persist into early night. However, there are
signs of MVFR cigs returning overnight, thus prevailing MVFR groups
have been included from 02Z-12Z Wednesday.

Extended Aviation Outlook: Brief flight restrictions are possible in
showers and thunderstorms, mainly in the afternoon and evenings
through the period.

&&

.MARINE...
Winds are howling over the waters north of the Savannah River
Entrance this morning where pinched gradient conditions are
occurring. Gusts in excess of 30 kt have been observed at times.
The Small Craft Advisory was extended south to include the
Edisto Beach to Savannah nearshore waters and a Marine Weather
Statement was issued to address winds near 30 kt at the Savannah
River Entrance where especially rough conditions are likely. The
advisory runs through 2 PM.

Today and Tonight: A fairly enhanced pressure gradient has developed
across northern SC waters off the Charleston County coast outside of
convection. Given recent obs across local waters a Small Craft
Advisory is now in effect until 2 PM for gusts around 25-30 kt and
seas up to 4-6 ft. Thereafter, guidance continues to indicate that
the gradient will begin to relax while a ridge of high pressure
persists aloft. Otherwise, expect northeast winds between gusting
around 20 kt outside shower/thunderstorm activity across southern SC
nearshore waters and nearshore GA waters, and more easterly and
light south of a stalled front/boundary across offshore Georgia
waters. Overnight, the front should begin to drift south of local
waters and/or dissipate, but showers and thunderstorms will continue
to pose localized higher wind gusts and reduced vsbys at times until
that occurs. Outside of this activity, winds should gradually weaken
(10-15 kt) and seas should subside to 2-4 ft.

Wednesday through Sunday: Northeast/east winds initially will turn
southerly by late week. Marine conditions should stay solidly below
small craft advisory criteria with speeds 15 knots or less and seas
no higher than 4 feet.

&&

.TIDES/COASTAL FLOODING...
If current tide trends continue, a Coastal Flood Advisory will
likely be issued for Charleston and Coastal Colleton with the
early afternoon update to address a 7.2 ft MLLW tide in the
Charleston Harbor this evening.

Favorable onshore winds and the approach of the new moon will lead
to elevated tides over the next few days along the Charleston and
Colleton county coasts. Tides levels could approach minor coastal
flooding criteria of 7 ft MLLW in the Charleston Harbor. Further
south, no tide issues are expected.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for AMZ350-
     352.

&&

$$