North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

202
FXUS62 KCHS 212353
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
753 PM EDT Mon Sep 21 2026

.WHAT HAS CHANGED...
The Aviation section has been updated for the 00z TAF issuance.
Added a Key Message for coastal flooding potential mid to late
week.

&&

.KEY MESSAGES...
- 1) Rain chances increase on Tuesday.

- 2) A cold front could bring a threat of strong thunderstorms
  Wednesday afternoon, and will be followed by cooler weather
  and gusty winds.

- 3) The threat for coastal flooding will increase mid
to late week.

&&

.DISCUSSION...
KEY MESSAGE 1: Rain chances increase on Tuesday.

Through Tonight: Little change in the overall pattern has
occurred during the past 24 hours in regards to an upper low
meandering over Florida and deep moisture advecting across the
local area with PWATs near 2 inches. Shower activity could
linger into early evening hours, but should dissipate within a
few hours of sunset. Locations that see rainfall today will be
more at risk for patchy to areas of fog late tonight, especially
inland for a few hours prior to and around daybreak.

Tuesday: The aforementioned upper low across Florida will begin to
drift north across the Southeast United States, likely to bring
higher chances of showers/thunderstorms locally despite trending
weaker well in advance of a longwave trough making way across the
Midwest. The uptick in forcing along with modest instability and
residing 2+ inch PWATs could support a few stronger thunderstorms
during mid-late afternoon into early evening hours, perhaps with
some enhancement along/near a seabreeze. Localized heavy rainfall
and minor flooding issues are also possible. However, the overall
severe weather threat should be on the lower end.

KEY MESSAGE 2: A cold front could bring a threat of strong thunderstorms
Wednesday afternoon, and will be followed by cooler weather and gusty
winds.

The previously mentioned upper low is anticipated to shift north-
northeast of the local area, becoming phased with a longwave trough
shifting across the Mid-Atlantic and Northeast States mid-week. A
notable cold front is progged to push south into the local as the
mid-upper lvl pattern supports digging of the longwave trough across
the Southeast. Timing of fropa will remain key in regards to the
overall threat for stronger and/or marginally severe thunderstorms
Wednesday. Although latest trends suggest cold fropa beginning late
Tuesday night into Wednesday morning, there could be sufficient time
for strong sfc heating to occur within a deeply moist environment
across Southeast Georgia Wednesday afternoon, leading to a greater
risk for stronger and/or marginally severe thunderstorms prior to
sunset.

Following the front, an inland wedge will set up across the
Carolinas and Georgia, favoring cool and drier conditions locally
within a north-northeast flow during the second half of the week.
Cold air advection and a tightening pressure gradient should lead
to breezy conditions post fropa Wednesday and Thursday, with
some enhancement possible near coastal areas. In general, highs
temps in the mid-upper 70s to lower 80s for Southeast SC and
low/mid 80s for Southeast GA are most probable into late week.

KEY MESSAGE 3: The threat for coastal flooding will increase mid
to late week.

As a full moon approaches on 9/26, breezy northeast winds
Wednesday evening into Friday may result in some coastal
flooding issues as tidal departures rise. We will need to keep
an eye on the potential starting as early as Wednesday afternoon
for coastal Charleston and Colleton counties, expanding
southwards to include the remainder of the SE SC coast into SE
GA Thursday afternoon/evening.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR is expected to prevail through at least the first half of
the night. Thereafter, guidance hints that another round of
stratus and fog will be possible. The greater chance for
occurrence is at KSAV where MVFR has been maintained, though
there is potential for IFR or lower. VFR should return mid
morning. Brief restrictions in showers/thunderstorms will be
possible in the afternoon, which is currently highlighted with
PROB30 groups.

Extended Aviation Outlook: Flight restriction chances increase
Tuesday into Wednesday at all terminals with a showers and
thunderstorms and a building wedge post fropa Tuesday night
into Wednesday. Gusty north-northeast winds are likely to follow
at all terminals Wednesday into Thursday as well.

&&

.MARINE...
Through Tuesday: A decaying surface high pressure ahead of a slowly
approaching cold front will continue the benign marine weather
conditions across our local waters. Periodic showers and
thunderstorms during this time may be capable of gusty winds and
frequent lightning.

Wednesday-Friday: A cold front will be pushing through on Wednesday,
with a strong surge in northeasterly flow as the pinched pressure
gradient (aka the wedge) sets up. Breezy ramp up during the evening
hours, with wind gusts in excess of 25 knots have 60-90% chances, so
Small Craft Advisories are anticipated. There is also a low chance
(20-30%) for Gales to develop on Thursday, for the zones 20+nm
offshore. In addition, wave heights of 5-7 ft will likely accompany
the breezy winds for areas 15+ nm away from the coast Thursday
morning through Friday evening before winds begin to weaken.

Saturday: The wedge continues to weaken, further decreasing the wind
strength throughout the day. Seas will remain unsettled, with
offshore zones (20+nm offshore) seeing 6ft+ waves continuing into
the evening hours before decreasing below 6 ft.


&&

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

&&

$$