North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

251
FXUS62 KCHS 191847
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
247 PM EDT Sat Sep 19 2026

.WHAT HAS CHANGED...
All sections have been updated.

&&

.KEY MESSAGES...
- 1) Daily thunderstorms are expected across southeast Georgia
 and southeast South Carolina this weekend and into early next
 week. An increase in rain chances is expected by the middle of
 next week, with cooler temperatures thereafter.

&&

.DISCUSSION...
KEY MESSAGE 1: Daily thunderstorms are expected across
southeast Georgia and southeast South Carolina this weekend and
into early next week. An increase in rain chances is expected by
the middle of next week, with cooler temperatures thereafter.

Through tonight: Aloft, the forecast area will sit within the
eastern extent of ridging centered near the ArkLaTex and on the
northern periphery of a closed low over the FL peninsula. At the
surface, the setup is pretty diffuse, but generally features
weak high pressure just off the coast. Diurnal shower and
thunderstorm development will be largely dependent on surface
heating and modest convergence along a weak sea breeze this
afternoon and evening. Model guidance is in decent agreement
that convective initiation should take place along the SC coast,
especially north of the Santee along the Grand Strand where
satellite imagery shows some differential heating boundaries.
Thunderstorm activity should then gradually progress to the
southwest along the sea breeze and the southeast SC coast. The
best coverage is anticipated to be centered across an area from
Beaufort/Jasper/Colleton counties and to the southwest into
southeast GA into the evening hours. The environment isn`t
particularly interesting with MLCAPE values in the 1,500-2,000
J/kg range and DCAPE values topping out around 800 J/kg or so.
Flow through the column is 10-15 knots at best. While we can`t
completely rule out 1 or 2 strong to marginally severe storms,
the overall severe threat is low. With precipitable water values
over 2 inches, there will be potential for locally heavy
rainfall. Thunderstorm coverage should steadily diminish through
the evening and also continue to shift to the southwest.

Sunday through the middle of the week: Sunday should be similar
to Saturday with diurnal convection driven by the sea breeze
and coverage in the isolated to scattered range. Monday should
also bring about rather modest coverage mainly in the form of
diurnal convection. Better convective coverage and higher rain
chances are anticipated Tuesday into Wednesday as a front
approaches from the north. There could be a threat of locally
heavy rainfall during this mid week time period as coverage
increases in the presence of precipitable water values in excess
of 2 inches.

Behind the mid week cold front, noticeably cooler air is
expected for the latter part of the week. Highs in the upper 70s
to low 80s for southeast SC and low to mid 80s for southeast GA
look probable at this time, which would be a few degrees below
normal for late September.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
The 18z TAF period begins with VFR conditions at KCHS, KJZI,
and KSAV. The first forecast concern is for afternoon and
evening thunderstorm impacts. Thunderstorms are expected to
develop along the sea breeze this afternoon, likely occurring
near KCHS and KJZI first and PROB30 groups are in place in the
21-23z time period. KSAV should come a bit later and a PROB30
group is in effect from 22-00z. Thunderstorms should move to the
southwest and away from the terminals through the late evening
hours. The next potential forecast issue is for low stratus and
fog to spread into the terminals from inland around sunrise
Sunday. Model guidance is still mixed regarding the extent of
fog/stratus and how low flight categories could be. For now we
maintained MVFR ceilings starting around 10-11z, but there is
definitely potential for IFR conditions. Whatever fog/stratus
does develop should mix out and dissipate by mid morning Sunday.

Extended Aviation Outlook: The main potential for sub-VFR
conditions will come from afternoon and evening showers and
thunderstorms each day. The best chance of showers and
thunderstorms is expected to come Tuesday into Wednesday.

&&

.MARINE...
Through tonight: Very quiet conditions will continue across the
local waters. Light onshore flow this evening will remain light
and turn more northeasterly overnight. Seas are expected to
average around 2 ft. A few thunderstorms will be possible along
the coast this evening, potentially producing gusty winds and
frequent lightning.

Sunday through Thursday: Conditions across the local waters
will remain quiet through Monday with northeast or east flow
generally no more than 10 knots. However, this will change as we
get into the middle of the week and a cold front pushes through
from the north. This will result in a strong surge of northeast
flow beginning Wednesday and continuing through Thursday. There
will be increasing probabilities of gusts into the 25-30 knot
range with seas building upwards of 6 ft as well. Small Craft
Advisories will likely be needed for some, if not all, of the
local waters including Charleston Harbor. Also of note, rounds
of thunderstorms will be possible at times ahead of an along the
front which could bring the potential for strong wind gusts and
frequent lightning.

&&

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

&&

$$