531
FXUS62 KCHS 071756
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
156 PM EDT Mon Jul 7 2025

.SYNOPSIS...
Weak high pressure holds tight across the region through the
week, with typical summertime convection possible daily along
the advancing sea breeze.

&&

.NEAR TERM /THROUGH TONIGHT/...
This Afternoon: Aloft, mid-lvl vort energy continues to depart
further away from the region to the north while a ridge centered
across the Atlantic expands across the Mid-Atlantic and Southeast
states in its wake. At the sfc, the local area remains nestled
between an Atlantic high centered offshore and weak troughing across
the Midlands/Upstate. The pattern supports conditions similar to
those expected during the summertime, with few to scattered
showers/thunderstorms occurring along an inland moving sea breeze
mid-late afternoon and remaining mostly pulse like/sub-severe in
nature. However, a plume of tropical moisture remains across the
Southeast in wake of Chantal with PWATs around 2.00-2.25 inches and
strong sfc heating should support SBCAPE values near 3500-4000 J/kg,
suggesting the potential for a few stronger thunderstorms and/or
isolated severe thunderstorm along/ahead of the sea breeze
circulation mid-late afternoon. Shear will remain weak, but strong
instability, low-lvl lapse rates near -7.5 to -8 C and DCAPE
approaching 700-900 J/kg, suggests an isolated damaging wind threat.
Slow storm motions and deep moisture also support brief heavy
downpours in some spots, which could necessitate a Flood Advisory
should activity persist near boundary/outflow interactions.

Temps will be warm with high pressure in control and ample sfc
heating occurring. 1000-850 mb thickness values support highs in the
mid to perhaps upper 90s inland, while an inland moving sea breeze
and onshore wind limits temps to the upper 80s/lower 90s closer to
the coast. Ample low-lvl mixing will help lower sfc dewpts to the
upper 60s/lower 70s inland during peak heating, limiting heat index
values to the 100-105 degree range, but some pooling of moisture
along the sea breeze could briefly support heat index values in the
105-108 range, highest in spots across the Tri-County Area. At this
time, the duration of higher heat index values does not appear
sufficient to support a Heat Advisory.

Tonight: Any lingering convection occurring near sunset will likely
dissipate early evening with the loss of day-time heating and
weakly sheared environment in place. Although an isolated shower can
not be ruled out, most areas are expected to be dry by mid-late
evening, then remain dry through the night. Winds will decouple
early with high pressure in control across the Southeast, leading to
light/calm winds for most locations away from the beaches. Conditions
will remain mild/humid with lows only dipping into the mid 70s
inland to around 80 near the beaches and Downtown Charleston.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
High pressure remains offshore Tuesday, with a subtle trough of low
pressure situated inland. Thus, expect the typical summertime sea
breeze to dominate. In terms of coverage, expect any convection to
remain isolated to scattered in nature, mainly during the afternoon
to early evening. Certainly enough instability to work with (upwards
of 1000 J/kg), though sfc and bulk shear values remain quite meager.
Latest soundings also showcase PWATs above 2 inches. So, as noted in
the previous discussion, can`t rule out quick bouts of heavy
rainfall, especially with limited storm motion. Breezy winds and
lightning will also be possible with any storm, with the overall
severe threat expected to remain minimal. Rain chances then increase
Wednesday and Thursday as weak shortwave develops across the
Tennessee Valley.

In regard to temperatures, look for highs Tuesday to warm into the
mid to upper 90s with dewpoints in the low to mid 70s. This will
result in heat index values between 100 - 106 degrees, with the
warmest values occurring across our interior Georgia counties. While
these values are expected to remain below Advisory levels, still
encourage folks to stay hydrated and take frequent breaks from the
heat. Otherwise, look for highs to be a touch "cooler" Wednesday and
Thursday as temperatures in the upper 80s to lower 90s become
common.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Overall synoptic pattern holds steady through the extended period,
with perhaps some weak ridging starting to develop across the Ohio
River Valley heading into the weekend. At the sfc, this will
translate to daily chances for showers and storms, especially during
the afternoon and early evenings as the sea breeze moves inland.
Temperatures look to remain seasonal during this time, with highs
generally in the low to mid 90s. Overnight lows will also remain
quite mild, as temperatures only fall into the low to mid 70s.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Prevailing VFR conditions are expected at CHS/JZI/SAV terminals
through 18Z Tuesday. However, isolated to scattered showers/thunderstorms
could impact the terminals this afternoon, leading to TEMPO
flight conditions. TEMPO MVFR conditions due to -TSRA has been
added to CHS from 18-19Z and to SAV from 18-20Z as a result, but
additional TEMPO flight restrictions could become necessary
late afternoon, mainly at SAV. Additional showers and thunderstorms
could impact the terminals Tuesday afternoon, but timing and
probabilities are too low to include in the latest TAF issuance.

Extended Aviation Outlook: Typical summertime convection pattern
will bring periodic flight restrictions through mid-week.

&&

.MARINE...
This Afternoon: Aloft, mid-lvl vort energy continues to depart the
region to the north while an expansive ridge takes shape across the
Atlantic. At the sfc, local waters will remain along the western
periphery of the Atlantic high while weak troughing occurs well
inland, favoring winds that back to the south as a sea breeze
develops/shifting inland. Winds will generally remain in the 10-15
kt range, although a few gusts up to 15-20 kt are possible in the
Charleston Harbor as the sea breeze shifts inland.

Tonight: The pressure gradient will remain rather weak with Atlantic
high pressure in control across the region. South winds are expected
to veer back to southwest during the night and generally remain
around 10 kt. Seas will average between 2-3 ft.

Tuesday through Saturday: Relatively benign conditions are forecast
and as a result no marine concerns expected during the period.
Southwest flow will persist with high pressure to the east. Wind
speeds will be 15 kt or less and seas will average 2-3 ft.

Rip Currents: Lingering swell and enhanced winds with the sea
breeze along the Charleston County coast will support a Moderate
Risk for rip currents this afternoon. The risk is low elsewhere.

&&

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

&&

$$

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