North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

050
FXUS62 KCHS 121101
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
701 AM EDT Wed Aug 12 2026

.WHAT HAS CHANGED...
The Aviation section has been updated for the 12Z

&&

.KEY MESSAGES...
- 1) A Heat Advisory is in effect for the coastal counties this
  afternoon and an Extreme Heat Watch is now in effect for those
  same counties Thursday afternoon. Additional Heat headlines
  will likely be required through the week and into the weekend.

- 2) Isolated to scattered thunderstorms will develop across
  southeast Georgia and the lower South Carolina Lowcountry,
  especially near the coast. One to two storms across extreme
  southeast Georgia may produce strong to severe wind gusts this
  afternoon. Additional thunderstorms are possible across
  portions of the region late Thursday.

&&

.DISCUSSION...
KEY MESSAGE 1: A Heat Advisory is in effect for the coastal
counties this afternoon and an Extreme Heat Watch is now in effect
for those same counties Thursday afternoon. Additional Heat
headlines will likely be required through the week and into the
weekend.

Heat headlines are likely into the weekend as heat index values soar
into the 100-110 range each afternoon through mid-week and upwards
of 115 late in the week. The daily record highs and record high
minimum temperatures will likely be challenged at our three climate
sites (see Climate Section for more details). Given the very mild
overnight periods and minimal coverage of precipitation, there will
be few instances of relief from the heat this week and into the
weekend.

Today: Ridging aloft will dominate over the southeastern states
today, with high temperatures reaching into the mid 90s. With
prevailing W to even NW flow at the surface the sea breeze will
likely be slow to progress inland, remaining pinned at the coast
into the early afternoon. However, dew points along the coastal
counties are still forecast to reach into the mid 70s, yielding heat
index values upwards of 110. A Heat Advisory is in effect for the
coastal counties today from 11 AM to 8 PM.

Thursday and Friday: The ridging aloft amplifies towards the end of
the week, likely bringing the warmest temperatures of the heat wave.
Highs on each day will likely reach into the upper 90s, with a brief
moment of touching 100 not out of the question. Heat index values
west of I-95 will likely reach 105-108 (Heat Advisory) with
locations east of I-95 reaching heat index values as high as 115. An
Extreme Heat Watch is now in effect for the coastal counties for
Thursday afternoon.

This Weekend: The center of ridging aloft will shift slightly
westward, resulting in a slight downtick of temperatures. However,
heat index values are still forecast to reach upwards of 110 along
the coastal corridor likely necessitating additional Heat
Advisories.

KEY MESSAGE 2: Isolated to scattered thunderstorms will develop
across southeast Georgia and the lower South Carolina Lowcountry,
especially near the coast. One to two storms across extreme
southeast Georgia may produce strong to severe wind gusts this
afternoon. Additional thunderstorms are possible across portions of
the region late Thursday.

Wednesday: The center of 595 DM ridge is forecast to slide west over
the northern Gulf. As a result, NW to SE heights may align over the
forecast area. The mid-level flow should remain a bit chaotic due to
the deep convection upstream. Satellite water vapor indicates
several disturbances, some on pace to ripple over the forecast area
this afternoon. Light wnw flow may keep the sea breeze pinned to the
coast until mid-afternoon. Following the HREF for timing and
placement of showers and thunderstorms, the forecast will feature
SCT to ISO PoPs. This is much greater that coverage indicated by
recent runs of the HRRR and RRFS. Given moderate instability and
DCAPE between 800-1000 J/kg, one or two thunderstorms between the
Altamaha and Savannah Rivers may produce strong to severe wind
gusts.

Interestingly, the 0Z GFS shows an MCS tracking from the Upstate to
the Coastal Plain this evening. Given the mid-level heights and
lingering elevated instability, the potential for an MCS reaching
the forecast area seems plausible. However, HREF and NAM12 indicates
that upstream convection will dissipate before reaching the CWA.

Thursday, H5 ridge will build west over the Deep South by the
afternoon and evening. Near term guidance, especially the NAM12,
indicates that a well-defined shortwave will reach the forecast area
late Thursday afternoon into the early evening. If this feature
arrives during the heat of the afternoon, then a solid band of
thunderstorms may develop across the Midlands, tracking across over
the Lowcountry. At this time, the forecast will feature a band of
SCHC PoPs moving west to east late Thursday afternoon.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
12Z TAFs: The terminals will remain between a broad trough
across the central Carolinas and Georgia and high pressure over
the western Atlantic. This pattern will yield west-southwest
winds across the terminals through the TAF period. Sea breeze
thunderstorms area possible at each terminal this afternoon,
highlighted with PROB30 at KCHS and KJZI and TEMPO at KSAV from
20-24Z. Convection should dissipate early this evening.

Extended Aviation Outlook: Prevailing VFR.

&&

.MARINE...
The pressure pattern will support southwest winds between 10 to 15
kts today, shifting from the west tonight. Wave heights are forecast
to remain between 2 to 3 ft. Isolated to scattered thunderstorms may
push over the nearshore waters late this afternoon and evening. One
or two of these storms may produce wind gusts in excess of 34 kts,
especially the nearshore GA and lower SC waters.

Thursday through Sunday: Conditions are expected to remain below
Small Craft Advisory criteria this week and into the weekend. A weak
coastal trough will set up across the marine waters this week,
persisting into the start of the weekend. This set up will keep
conditions across the marine waters breezy with southwesterly winds
gusting around 15 to 20 knots. 2 to 3 ft seas are expected across
the marine zones this week.

Coastal Flooding: While elevated tidal cycles are expected today
due to the recent perigee and new moon, the south-
southwesterly surface flow should keep tidal departures low,
limiting the overall coastal flood threat. For the evening high
tide this evening (occurring at 930 PM in the Charleston
Harbor), tide levels look to peak around 6.7-6.8 ft MLLW, with
some probabilistic guidance indicating only a 10% chance of
reaching 7.1 ft MLLW.

&&

.CLIMATE...
Record High Temperatures:

August 12:
KCHS: 98/1957
KCXM: 98/1998
KSAV: 100/1999

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 12:
KCHS: 79/1999
KSAV: 80/1878

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 this morning to 8 PM EDT this evening
     for GAZ217>219-239>241.
     Extreme Heat Watch from Thursday morning through Thursday
     evening for GAZ217>219-239>241.
SC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for SCZ148>152.
     Extreme Heat Watch from Thursday morning through Thursday
     evening for SCZ148>152.
MARINE...None.

&&

$$

CPM/NED