775
FXUS62 KCHS 272220
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
620 PM EDT Mon Jul 27 2026

.WHAT HAS CHANGED...
Key Message 1 and 2 were updated. The Aviation section was
updated.

&&

.KEY MESSAGES...
- 1) Isolated strong to severe thunderstorms possible Tuesday
  evening. The primary threat will be damaging wind gusts.

- 2) Dangerous heat and humidity will impact Southeast Georgia
  and Southeast South Carolina through the middle of the week.

&&

.DISCUSSION...
KEY MESSAGE 1: Isolated strong to severe thunderstorms possible
Tuesday evening. The primary threat will be damaging wind
gusts.

High resolution guidance indicates that a squall line will
develop over NC ahead of cold front Tuesday afternoon. This line
should track rapidly to the SE, with the southern portion of
the line expected to reach the Charleston Tri-county during the
evening hours. These storms may not arrive over Berkley and
Dorchester Counties until after sunset Tuesday evening.
Instability across the forecast should begin to decrease in
storms should decrease in intensity. However, if storms outpace
the guidance, then the risk of severe weather will increase
significantly. At this time, one or two of these storms may
remain organized with decent structure, these storms could
produce swaths of strong to damaging wind gusts.

KEY MESSAGE 2: Dangerous heat and humidity will impact Southeast
Georgia and Southeast South Carolina through the middle of the
week.

Tuesday and Wednesday: Strong mid-level ridging continues over the
Rockies and Plains through mid-week, with the eastern periphery
building into the southeastern CONUS. Meanwhile, at the sfc, will
also see a weak high pressure develop over the southeast, causing
oppressive heat to persist. In regard to temperatures, currently
have highs soaring into the mid to upper 90s and dewpoints in the
mid to upper 70s, with the highest values occurring along the
coastal corridor behind the sea breeze. With minimal precipitation
chances in place, believe heat index values up to 110 degrees will
prevail long enough in both extent and duration to warrant
headlines. Thus, after collaboration with neighbors, have issued an
area wide Heat Advisory that will be in effect Tuesday between 11-7
PM. Some areas could approach or even exceed Extreme Heat Warning
criteria within the coastal corridor, so monitoring for a possible
upgrade.

Similar conditions look likely Wednesday, though an advancing front
may possibly limit the extent/duration of heat. For now, have
afternoon highs in the mid to upper 90s and dewpoints in the low to
mid 70s, with the highest occurring along the coastal corridor
again. Will continue to monitor trends in regard to the
aforementioned front, but additional headlines may eventually be
needed as heat index values approach 110 degrees.

We encourage folks to stay hydrated, take frequent breaks in the
shade or AC, and to check on vulnerable populations like children
and elderly.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
28/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR through 29/00z. The remnants of a squall line
could approach KCHS and KJZI Tuesday evening.

Extended Aviation Outlook: Brief flight restrictions are possible
Wednesday and Thursday due to showers and thunderstorms.

&&

.MARINE...
Through Tonight: Overall, the gradient across the local waters will
be quite weak through the period. Winds will be strongest this
afternoon and evening with the development of the sea breeze along
the land/sea interface. Wind speeds should mostly top out in the 10-
15 knot range during this time period. Seas are expected to average
around 2 feet, but could be up to 3 feet in the outer waters.

Tuesday through Saturday: As a front approaches the marine waters
late on Tuesday night into Wednesday morning, winds and seas are
forecast to surge. Wind gusts could approach 25 knots across
portions of the marine waters, with the greatest chances between 20
to 60 nm offshore GA waters. Small Craft Advisories may be required
late Tuesday into Wednesday. Thereafter, marine conditions will
remain below Small Craft Advisory criteria into the weekend.

&&

.CLIMATE...
Record High Temperatures:

July 28:
KCHS: 101/1949
KCXM: 100/1936
KSAV: 102/1949

July 29:
KCHS: 100/1993
KCXM: 99/1999
KSAV: 103/1993

Record High Minimum Temperatures:

July 29:
KCHS: 80/2016
KCXM: 85/1999
KSAV: 82/1878

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM to 8 PM EDT Tuesday for GAZ087-088-
     099>101-114-115-137-216>219-238>241.
     Heat Advisory until 7 PM EDT this evening for GAZ137-216>219-
     238>241.
SC...Heat Advisory from 11 AM to 8 PM EDT Tuesday for SCZ040-
     042>045-147>152.
     Heat Advisory until 7 PM EDT this evening for SCZ148-151.
MARINE...None.

&&

$$