North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

374
FXUS62 KCHS 180642
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
242 AM EDT Fri Sep 18 2026

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

&&

.KEY MESSAGES...
- 1) Warming temperatures and mostly dry conditions today. Rain
  chances will then gradually increase this weekend and
  especially by early next week.

&&

.DISCUSSION...
KEY MESSAGE 1: Warming temperatures and mostly dry conditions
today. Rain chances will then gradually increase this weekend
and especially by early next week.

Recent runs of the HRRR indicated that sfc condensation pressure
deficits are forecast to lower below 3 mbs across the I-26 corridor
during the pre-dawn hours. We will continue to monitor IR satellite
and observations for any indication of fog formation. It is possible
some patchy fog or ground may develop across Dorchester, Berkeley,
and Charleston Counties this morning. Any fog that develops should
dissipate during the first hour or two of daylight.

Today, the forecast area will remain between a closed low over
central FL and a H5 ridge axis running west to east across NC.
Forecast soundings indicate a dry mixed layer with weak lapse rates
between 800-500 mb through this afternoon. The forecast will remain
dry today. High temperatures are forecast to range in the low to mid
90s this afternoon.

Convection-allowing models show a band of thunderstorms developing
from the Midlands east across the Pee Dee region late this afternoon
into this evening ahead of a sfc trough. These storms should push
south, but should weaken as they reach an increasingly stable
environment across SE GA and the Lowcountry. The forecast will
feature a tier of SCHC PoPs across inland SC for showers and
thunderstorms this evening. Any deep convection should dissipate
before midnight. Low temperatures should range between 70-75
degrees.

The overall pattern will change this weekend as a weak cold front
approaches from the north. Transport of deep moisture will drive
precipitable water values up to 2.1-2.3 inches by Saturday evening.
This set up will favor unsettled conditions and increased rain
chances this weekend. Given the moisture-rich airmass and the
presence of rounds of convection (primarily in the afternoon and
evenings), there will be at least a low end threat for locally heavy
rainfall. However, minimal shear and modest instability will limit
the severe weather threat.

An unsettled pattern could continue into the middle of next week as
a stronger cold front advances across the area.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
6Z TAFs: Recent runs of the HRRR indicated that sfc condensation
pressure deficits are forecast to lower below 3 mbs across KCHS and
KJZI during the pre-dawn hours. However, LAMP guidance indicates
some fog potential at KSAV between 10-12Z. We will monitor
observations overnight, the addition of fog in the TAFs is possible
given clear sky and light to calm winds. After daybreak, VFR
conditions with light northwest winds this morning. A weak sea
breeze should advance across the terminals between 19-20Z, turning
winds from the southeast.

Extended Aviation Outlook: Rain chances are expected to increase
late this weekend and into early next week which could result in
periodic flight restrictions.

&&

.MARINE...
Today and tonight: Light northeast winds this morning should turn
from the southeast this afternoon following the sea breeze. Winds
may veer from the southwest tonight, speeds less than 10 kts. Wave
heights should continue to diminish today, settling to around 2 ft
tonight.

Saturday through Wednesday: Winds and seas are expected to remain
well below Small Craft Advisory thresholds through the period. Winds
will be 10 knots or less for much of this period, with seas
generally in the 2-3 ft range. The main forecast concern will be
increasing coverage of showers and thunderstorms across the local
waters, especially early next week.

&&

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

&&

$$

BRS/NED