307
FXUS62 KCHS 141500
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1100 AM EDT Sun Jul 14 2024

.SYNOPSIS...
Atlantic high pressure and a weak inland trough will extend
across the region through the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: The remnants of a stationary front will likely dissipate
across the interior while broad mid-upper lvl ridging holds across
the Southeast United States aloft. The region will remain along the
western periphery of sfc high pressure while weak lee troughing
develops well inland to the local area for the remainder of the day.
Convection should remain rather sparse and develop a few hours later
than the previous day given a substantial amount of subsidence
resulting from high pressure and a downsloping wind component aloft.
This will in return allow sfc temps to warm a few degrees higher
than yesterday as well with strong diurnal heating occurring under
less clouds and a few hour delay in precipitation. Showers and/or
thunderstorms that do develop early to mid afternoon should be pulse
type in nature, highly dependent on instability in place given a
lack of shear and forcing mechanisms. A sea breeze could provide a
focusing mechanism for initiating activity by mid afternoon, slowly
shifting inland after being pinned closer to the coast due a west-
southwest sfc wind through late morning hours. Although organized
severe weather will remain quite low this afternoon, a stronger or
even marginally severe thunderstorm can not be ruled out during
boundary interactions in an environment displaying SBCAPE around
4500 J/kg and PWATs around 2.0 inches closer to the coast, and low-
lvl lapse rates around 8.5 C/kg and DCAPE values around 1000-1200
J/kg further inland. Strong/damaging wind gusts along with brief
heavy downpours will be the primary concern should a stronger
thunderstorm develop mid to late afternoon. Similar to yesterday,
expect convection to wane heading closer to sunset given diurnal
heat loss in a weakly sheared environment. However, it`s not out of
the question for a few showers/thunderstorms to persist along
boundary interactions.

It will be another hot and humid day. Both low-level thicknesses and
850 hPa temperatures will nudge higher through the day with current
data supporting highs near 100 across far interior Southeast Georgia
to the lower-mid 90s across coastal counties. Sfc dewpts should mix
out to the mid-upper 60s roughly west of a Hampton-Glennville line
with mid-upper 70s east of the I-95 corridor. Given these
conditions, heat indices should max out in the 108-112 range east of
I-95 and the 102-107 range well inland. A Heat Advisory will remain
in place for areas along/east of I-95 from noon through 7 PM EDT. A
few spots along the Charleston and Colleton County coasts could see
dewpoints pool into the lower 80s for a few hours this afternoon,
which could briefly push heat indices to 113-115. These instances
should remain fairly localized and brief before showers and
thunderstorms develop near a sea breeze, so an Excessive Heat
Warning will not be issued at this time.

Tonight: Any lingering convection should quickly end after
sunset with dry conditions prevailing through the overnight
period. It will remain warm and humid with lows from the mid 70s
well inland to the lower 80s at the beaches and Downtown
Charleston.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
The region will be positioned along the western edge of broad
ridging aloft through the middle of the week. At the surface
high pressure will be centered well offshore, building into the
forecast area from the east. Lacking any significant source of
forcing afternoon showers and thunderstorms will be driven by
the local sea- breeze and additional boundary interactions.
Scattered to numerous showers and thunderstorms will be possible
each afternoon. Locally heavy rainfall will be possible, with
limited steering flow and PWATs around or just above 2 inches.

Hot and humid conditions are expected each day, with Heat Index
values of 105-110F forecast each afternoon. Heat Advisories
will likely be required, mainly along and east of I-95. It is
worth noting that afternoon convection would limit Heat Index
potential. Overnight lows will provide little relief from the
warm temperatures, with lows only dipping into the mid 70s
inland and around 80 at the beaches. The record high minimum
temperature could be challenged at the KCHS and Downtown
Charleston climate sites (if convection doesn`t impact the
temperature). See Climate section for more details.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The ridging aloft will begin to retreat to the east as a mid-
level trough swings towards the East Coast late in the week. At
the surface high pressure will also retreat back over the
Atlantic as a cold front approaches the region. A rather wet
pattern appears to set up late in the week as PWATs increase to
over 2 inches as the cold front approaches. The forecast
currently features scattered to numerous showers and
thunderstorms each afternoon, with PoPs increasing each
afternoon through the period. With the additional cloud cover
and precipitation Heat Index values will likely remain below
Heat Advisory levels after Thursday.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
14/12Z TAF Discussion:
KCHS/KJZI/KSAV: VFR. Isolated showers/tstms are starting to pop
along a weak land breeze early this morning. This could run in
the vicinity of KCHS and KJZI by 12z. Confidence is not high
enough to include a mention at this time, but a last minute
check at radar prior to issuance time will dictate if a VCSH or
VCTS is warranted for either terminal. Otherwise, the risk for
isolated, afternoon showers/tstms is too low to include a
mention at any of the terminals this afternoon.

Extended Aviation Outlook: Scattered afternoon showers/tstorms
could produce brief flight restrictions at all terminals through
the middle of next week. Late week precipitation chances will
begin to increase, increasing the risk for flight restrictions.

&&

.MARINE...
Through Tonight: Southwest to south winds 10-15 kt will prevail
through the period as the waters remain along the western
periphery of the Bermuda High. Seas will average 2-4 ft.

Monday through Thursday: High pressure will prevail across the
marine zones through the middle of the week. Thereafter, a cold
front will approach the inland zones, creating a slightly
pinched pressure gradient between the approaching cold front and
the high pressure over the marine waters. However, conditions
are expected to remain below Small Craft Advisory criteria.
Generally S winds are forecast, 10-15 knots. Slightly stronger
wind speeds are possible along the direct coastline in
association with the afternoon sea breeze. Seas should average 3
to 4 ft.

&&

.CLIMATE...
Record High Minimum Temperatures:

July 15:
KCHS: 81/1981
KCXM: 82/2023
KSAV: 80/1981

July 16:
KCHS: 78/2023
KCXM: 82/2021
KSAV: 82/1883

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory until 7 PM EDT this evening for GAZ116>119-
     138>141.
SC...Heat Advisory until 7 PM EDT this evening for SCZ043>045-
     047>052.
MARINE...None.

&&

$$

NEAR TERM...DPB
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...DPB