North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

226
FXUS62 KCHS 031018
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
618 AM EDT Mon Aug 3 2026

.WHAT HAS CHANGED...
Aviation section updated for the 12z TAFs. Marine section
updated to reflect a risk for waterspouts this morning.

&&

.KEY MESSAGES...
- 1) Continued unsettled through Tuesday with a risk for heavy
  rainfall, localized flooding and possibly an isolated strong
  to marginally severe tstm.

&&

.DISCUSSION...
KEY MESSAGE 1: Continued unsettled through Tuesday with a risk
for heavy rainfall, localized flooding and possibly an isolated
strong to marginally severe tstm.

Through Tonight: Early morning water vapor imagery shows a deep
trough extending through the Deep South into the Lower
Mississippi Valley with a continuous plume of tropical moisture
streaming out of the eastern Gulf and western Caribbean and
across the Southeast States. At the surface, the region remains
in the warm sector ahead of an approaching cold front with
Atlantic high pressure centered well offshore. The upper trough
to the west is forecast to propagates slowly east today while
Southeast South Carolina and Southeast Georgia remains within a
very moist and unstable environment. Conditions appear ripe for
anther round of showers/tstms today with PWATs near 2.50"
interacting with bands of vorticity maxima passing through in
the southwest flow aloft.

Convective temperatures in the mid 80s suggest convection may
get going a bit earlier than the past several days which will
likely have a limiting impact on the amount of available
instability given the increased cloud cover, less insolation and
cooler afternoon highs in the mid-upper 80s. While a considerable
amount of convection appears likely again today, its intensity
may be a bit more muted compared to the past few afternoons
given lower net mixed-layer instability will be realized. Still,
there will be a continued risk for heavy rainfall and localized
flooding with PWATs forecast to hold 2.20-2.45", especially
along/east of the I-95 corridor. The 850-250 hPa mean steering
flow looks to remain fairly robust (20-25 kt) ahead of the upper
trough so tstms should remain fairly progressive which should
limit rainfall at any one spot, despite intense hourly rainfall
rates nearing 2-3"/hr. This is reflected in both the HREF and
REFS which only show spotty 3-hour maximum QPF values peaking
2-3". Unless deep convection stalls along a mesoscale boundary
within either the Charleston or Savannah Metro Areas, the risk
for flooding looks fairly low-end and likely remaining confined
to low-lying and poor drainage areas (i.e. Flood Advisory
levels). An isolated severe tstm can not be completely ruled out
this afternoon with damaging wind gusts and cloud-to- ground
lightning being the primary hazards in addition to the broader
risk for heavy rainfall.

The greatest coverage of shower/tstms should end by early
evening. However, as low-level convergence shifts back into the
Atlantic closer to the west wall of the Gulf Stream overnight,
another round of showers/tstms is expected to develop over the
coastal waters. Some of this activity could brush the coast,
mainly from Hunting Island north into parts of the Charleston
Tri-County (especially the Charleston County).

Tuesday: A similar pattern is expected to persist into Tuesday
as a stationary front remains inland while a cutoff low stays
anchored over the Southeast. This setup will continue to support
periodic rounds of ascent and scattered showers and
thunderstorms. Although the axis of deepest moisture is forecast
to shift offshore, guidance still indicates pockets where PWAT
values could reach 2 inches or greater, remaining well above
climatological normals. Combined with modestly higher
instability (SBCAPE ~1500 J/kg), the environment will remain
favorable for additional rounds of showers and thunderstorms
capable of producing locally heavy rainfall and isolated
flooding. Similar to Monday, the highest QPF totals are expected
across the South Carolina coast, including the Charleston metro
area. The flood threat will be highly dependent on antecedent
conditions, as locations receiving heavy rainfall Sunday and/or
Monday will have limited time to drain before another round of
potentially heavy rain develops Tuesday. Meanwhile, pockets of
increasing mid-level dry air are expected to promote DCAPE
values approaching or exceeding 1000 J/kg. Therefore, an
isolated strong to severe storm is possible with damaging wind
gusts the primary hazard.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
03/12z TAF Discussion:
KCHS/KJZI/KSAV: An area of IFR cigs are still trying to get into
KSAV as daybreak approaches. Opted for a brief TEMPO through 13z
to try and capture this. Another convective active day is
expected for the terminals. Best chance for tstm impacts today
will be at KCHS and KJZI although KSAV still has modest chances
as well. TEMPO groups were included 19-22z at both Charleston
terminals where confidence is greatest and a PROB30 at KSAV for
the same time. Conditions were limited to MVFR for now, but IFR
can not be ruled out at times.

Extended Aviation Outlook: Periodic flight restrictions are
expected in showers and thunderstorms this week.

&&

.MARINE...
Through Tonight: Convection yesterday evening really disrupted
the wind field across the coastal water with winds observed
early this morning still holding below Small Craft Advisory
levels. Guidance still suggests winds will pick up over the
next few hours, assuming convection this morning does not become
too widespread. Small Craft Advisories were maintained for all
waters through this afternoon and the South Santee- Edisto Beach
nearshore leg until early this evening. The advisory for the
Charleston Harbor was allowed to expire. Seas 4-6 ft will
subside 3-5 ft in the advisory area this afternoon, but hold
near 6 ft in the offshore South Carolina waters where Small
Craft Advisories are not currently issued. Seas will further
subside to 2-4 ft overnight.

Tuesday through Saturday: Atlantic high pressure will remain
the dominant feature through the week resulting in generally
benign wind and sea conditions. Winds could briefly increase
along the coast during the afternoon and evening each day in
association with the sea breeze.

Rip Currents: A moderate rip current risk is in place for all
beaches through this evening for gusty winds and lingering
elevated seas. A moderate risk of rip currents is expected to
continue through Tuesday for the Charleston County beaches due
to lingering 2 foot swells at 8 seconds, combined with elevated
onshore flow. All other beaches from Edisto southward to Sapelo
Island are expected to have a low risk of rip currents for
Tuesday.

Waterspouts: Forecast sounding output and elevated non-supercell
tornado parameters values over the nearshore and offshore waters
look to support a risk for waterspouts this morning. Satellite
and radar already suggest a few cloud lines are trying to
develop over the Atlantic which could become the focus for
waterspouts through late morning. A Marine Weather Statement
was issued to alert mariners to this possibility.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for AMZ360.
     Small Craft Advisory until 5 PM EDT this afternoon for AMZ362-
     364-384.

&&

$$