283
FXUS62 KCHS 161151
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
751 AM EDT Sun Aug 16 2026

.WHAT HAS CHANGED...
The Aviation Section has been updated for the 12Z TAF issuance.

&&

.KEY MESSAGES...
- 1) Heat will remain a concern through the middle of the week.

- 2) Strong to severe thunderstorms are possible this afternoon.

&&

.DISCUSSION...
KEY MESSAGE 1: Heat will remain a concern through the middle of the
week.

Today: A warm pattern will remain in place with large-scale ridging
across the Deep South and Southeast United States. Much like the
previous couple days, strong heating this morning into early
afternoon should support high temps in the mid 90s away from the
immediate beaches. These temps along with sfc dewpts in the mid-
upper 70s (highest across coastal counties where impacts of mixing
out of low-lvl moisture is less likely) support heat index values in
the 106-111 range and the continuation of a Heat Advisory
across Southeast South Carolina and Southeast Georgia from 11 AM
to 8 PM. However, convective coverage should become a larger
influence today with scattered showers/thunderstorms developing
during peak heating hours. This could provide some relief from
the heat this afternoon, and possibly shorten the duration of
the Heat Advisory across some areas late day.

Monday and Tuesday: Hot/humid conditions will remain across the
Southeast United States through the middle of the week with large-
scale ridging centered across the Deep South and northern Gulf
regions. Record warmth is possible, especially as the heat wave
peaks with a downslope wind across the local area Monday and
Tuesday. Some areas could see temps peak around 100 degrees each
afternoon with little to no shower/thunderstorm activity. The setup
favors strong mixing out of sfc dewpts across inland areas, and
possibly east of I-95 should a sea breeze remain somewhat pinned
near the coast into early afternoon, leading to some questions to
maximum heat index values and duration during peak heating hours
both days. The combination of hot temperatures and sfc dewpts
in the low 70s inland and mid-upper 70s near the coast look to
favor at least Heat Advisory level conditions early week, and the
possibility of Extreme Heat Warning criteria across coastal
counties.

Wednesday and Thursday: There are signs of the expansive ridge
starting to weaken while scattered convection returns during peak
heating hours. We should see another day of Heat Advisory conditions
prior to showers/thunderstorms developing, especially along the
coastal corridor. Thursday remains hot, but with a similar trend in
the mid-upper pattern, although some hints of weak shortwave energy
rounding the northeast periphery of the ridge could deliver greater
cloud coverage and/or shower/thunderstorm activity to the region.
Additional heat headlines could be needed.


KEY MESSAGE 2: Strong to severe thunderstorms are possible this
afternoon.

The heat and humidity (mentioned in Key Message 1) will provide a
moderate amount of instability across our area this afternoon.
Models generally have SBCAPE values in the 2,000-2,500 J/kg range
across our area with locally higher peaks. Likewise, DCAPE values
should exceed 1,000 J/kg in some areas. There continues to be some
minor differences between the various CAMS and the deterministic
models. But when all of that is factored in, the general consensus
is that there should be isolated to scattered convection forming
along the sea breeze early this afternoon, and then shifting inland.
The outflow and boundary interactions should again play a major role
in storm formation and persistence. Given the aforementioned
instability and DCAPE, strong to severe thunderstorms are possible
across our entire area, with perhaps slightly higher potential south
of I-16. The main threat is damaging winds. Though, heavy rainfall
is also a concern due to the very weak steering flow. Backbuilding
and/or training of storms could drop enough rainfall to generate
very localized flooding with or maybe even flash flooding. The
convection may start to shift back towards the coast late in the
afternoon and early evening, but will then dissipate as the energy
diminishes with sunset.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected at CHS/JZI/SAV terminals through
about 18Z today. The risk for isolated to scattered showers
and/or thunderstorms increases during afternoon hours, and
possibly lingers into evening hours. PROB30 groups remain at
CHS/JZI/SAV terminals from 20-24Z today for thunderstorms (some
possibly strong with gusty winds) and MVFR conditions. VFR
conditions should then return by 02Z Monday and persist through
12Z Monday.

Extended Aviation Outlook: Periodic flight restrictions are expected
due to afternoon showers and thunderstorms Tuesday through Thursday.

&&

.MARINE...
Today and Tonight: Conditions are expected to remain quiet across
local waters between the western periphery of an Atlantic high and
weak troughing inland, although thunderstorms that develop over land
could shift offshore late afternoon into early evening hours and
produce gusty winds. Outside thunderstorms, light west/southwest
winds around 5 kt this morning should turn more southerly and gust
up to 10-15 kt this afternoon, then persist into evening hours,
before slowly weakening and returning to west/southwest overnight.
Seas should be no larger than 2-3 ft.

Extended Marine: There will be areas of High pressure in the western
Atlantic and the northern Gulf, while surface troughing will persist
over the Southeast U.S. The interaction between all of these
synoptic features will generate a typical summertime wind pattern.
Winds will generally be from the SW, backing a bit each day and
veering some each night. The strongest winds should be during the
day, especially closer to the coast due to the sea breeze. Seas will
mainly be in the 2-3 ft range.

&&

.CLIMATE...
Record High Temperatures:

August 16:
KCHS: 99/1954
KSAV: 100/1954

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

August 18:
KCHS: 101/1995
KCXM: 97/1995
KSAV: 100/1995

August 19:
KCHS: 98/1983
KSAV: 99/1900

August 20:
KCHS: 97/2005
KSAV: 102/1900

Record High Minimum Temperatures:

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

August 19:
KCHS: 79/2010
KCXM: 83/2021
KSAV: 79/1878

August 20:
KCHS: 78/2017
KCXM: 82/2017
KSAV: 82/1878

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ087-088-099>101-114-115-137-216>219-238>241.
SC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for SCZ040-042>045-147>152.
MARINE...None.

&&

$$