North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

657
FXUS62 KCHS 122322
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
722 PM EDT Wed Aug 12 2026

.WHAT HAS CHANGED...
Update to issue a Coastal Flood Advisory.

&&

.KEY MESSAGES...
- 1) Excessive heat will remain a concern into next week.

- 2) Risk for Thunderstorms through Thursday.

&&

.DISCUSSION...
KEY MESSAGE 1: Excessive heat will remain a concern into next
week.

Thursday into Next Week: This aforementioned ridge will
strengthen tomorrow (8/13) and Friday, yielding west-
northwesterly flow across the region. This will yield afternoon
highs from the mid to upper 90s (with some spots briefly hitting
100F). In addition to the extreme temperatures, it`ll be quite
humid outside with dewpoints in the mid to upper 70s. Expect
PWAT values to range from 2.0 to 2.2 inches with the highest
moisture generally located along and east of the I- 95 corridor.
Afternoon heat index values west of I-95 will likely reach 105F
to 108F with values reaching as high as 117F along and east of
I-95. Therefore, a Extreme Heat Warning has been issued for the
coastal counties from 11AM to 8PM tomorrow, and a Heat Advisory
has been issued for the rest of the forecast area for the same
timeframe. We will likely need heat headlines again for Friday
(8/14).

As this prominent ridge continues to linger across the
Southeast through the weekend and into early next week, expect
similar conditions to Thursday and Friday with heat index values
reaching upwards of 117F along the coastal corridor (along and
east of I-95) and ranging from 105F to 112F west of I-95. This
will likely necessitate additional heat headlines through early
next week.

KEY MESSAGE 2: Risk for Thunderstorms through Thursday.

Thursday: A prominent ridge will continue to build across the
Southeast tomorrow (6/13), with a well-defined shortwave
reaching the forecast area by late afternoon into the early
evening. Near- term guidance (HREF, HRRR, and NAM12) continues
to indicate a solid band of thunderstorms developing across the
Midlands and then tracking across southeast Georgia in the early
to late evening. Some showers and thunderstorms could initiate
in the afternoon (19-20Z) along the coastline as this shortwaves
nears the region. The environment will feature moderate
instability with SBCAPE values ranging from 2000 to 2500 J/kg
with weak shear (50 to 100 m^2/m^2), yielding the possibility of
a few strong to severe wind gusts within the stronger
thunderstorms.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 00z Friday. The main forecast challenge will be Thursday
late afternoon or evening thunderstorm potential. Confidence
isn`t particularly high, and the best thunderstorm potential
likely doesn`t begin until very late in the 00z TAF period.
Therefore, we have not introduced any mention of thunder at this
time.

Extended Aviation Outlook: Periodic flight restrictions are
expected in the afternoons with the chance of showers and
thunderstorms through the weekend.

&&

.MARINE...
Tonight: West to southwest winds will prevail through tonight.
Winds will remain less than 15 kt with seas 3 ft or less.

Thursday through Sunday: Marine conditions will remain on the
tranquil side as a weak coastal trough sets up across the
Atlantic tomorrow (8/13) and persists through the weekend.
Expect southwesterly winds to range from 10 to 15 kts with gusts
up 20 kts possible through the period. Weak south-southwesterly
swell will continue to taper into the waters through the
weekend yielding 2 to 3 ft seas.

Coastal Flooding: The evening high tide at Charleston is coming
up around 8:45 pm this evening. The current tide departure is
running around 0.7 ft and we only need 0.45 ft to reach 7.0 ft
MLLW. This tide departure will likely diminish through high tide
but it looks more likely we will hit 7.0 ft MLLW. Therefore, a
Coastal Flood Advisory has been issued for Charleston and
coastal Colleton counties.

&&

.CLIMATE...
Record High Temperatures:

August 13:
KCHS: 100/1995
KCXM: 98/1913
KSAV: 98/2010

August 14:
KCHS: 102/1995
KSAV: 102/1925

August 15:
KCHS: 96/2023
KCXM: 99/1918
KSAV: 100/1918

August 17:
KCHS: 102/1954
KSAV: 102/1954

August 18:
KCXM: 97/1995
KSAV: 100/1995

Record High Minimum Temperatures:

August 13:
KCHS: 81/2023

August 14:
KCHS: 80/2023
KCXM: 83/2023
KSAV: 80/2023

August 15:
KCHS: 78/1995
KCXM: 83/2021
KSAV: 80/1995

August 16:
KCHS: 78/2019
KCXM: 83/2016
KSAV: 78/2019

August 17:
KCHS: 80/2017
KCXM: 83/2017
KSAV: 78/2017

August 18:
KCHS: 80/2017
KCXM: 82/2017
KSAV: 78/2010

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM to 8 PM EDT Thursday for GAZ087-088-
     099>101-114-115-137-216-238.
     Extreme Heat Warning from 11 AM to 8 PM EDT Thursday for
     GAZ217>219-239>241.
SC...Heat Advisory from 11 AM to 8 PM EDT Thursday for SCZ040-
     042>045-147.
     Extreme Heat Warning from 11 AM to 8 PM EDT Thursday for
     SCZ148>152.
     Coastal Flood Advisory until 10 PM EDT this evening for SCZ149-
     150.
MARINE...None.

&&

$$