081
FXUS62 KCHS 281839
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
239 PM EDT Tue Jul 28 2026

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

&&

.KEY MESSAGES...
- 1) An isolated strong to severe thunderstorm will be possible
  late this evening, mainly for Charleston Tri-county. A few
  strong to severe thunderstorms are possible across extreme
  southern Georgia late Wednesday afternoon and evening. The
  primary threat will be damaging wind gusts.

- 2) Dangerous heat and humidity will impact southeast Georgia
  and southeast South Carolina through Wednesday.

&&

.DISCUSSION...
KEY MESSAGE 1: An isolated strong to severe thunderstorm will be
possible late this evening, mainly for Charleston Tri-county. A
few strong to severe thunderstorms are possible across extreme
southern Georgia late Wednesday afternoon and evening. The
primary threat will be damaging wind gusts.

Regional radar showed a developing squall line over the mid-
Appalachians this afternoon. This line should race southward,
reaching western NC by late this afternoon. The area ahead of the
squall line has been highlighted with a Severe Thunderstorm Watch
until 8 PM. DCAPE values are expected to range between 1000-1500
J/kg across the western Carolinas, likely supporting a deep cold
pool associated with the thunderstorms. Conditions ahead of the
storms across the Midlands of SC will begin to stabilize after sunset
this evening, however, enough elevated CAPE should be in place to
support deep convection. 12Z HREF indicates that 0-3 km SRH should
remain between 150-200 M2/s2 from the Midlands to the SC Lowcountry.
The elevated instability and adequate shear may allow some storm
clusters to remain fairly organized and possibly severe as the
storms reach northern Berkeley and Dorchester counties late this
evening. Therefore, a Severe Thunderstorm Watch may be needed for
Berkeley and Dorchester counties late this evening into early
Wednesday morning.

A cold front is timed to push over extreme southern GA late
Wednesday afternoon and evening. Given the hot and humid conditions,
moderate instability is forecast along and south of the front. High
resolution guidance indicates that a frontal wave may develop along
the front, possibly focusing an area of 0-1 km SRH in excess of 100
m2/s2. A few storms may develop very tall cores, possibly yielding
damaging winds below collapsing rain-loaded updrafts.

KEY MESSAGE 2: Dangerous heat and humidity will impact southeast
Georgia and southeast South Carolina through Wednesday.

Similar to yesterday, hot conditions continue to prevail across the
region, with latest observations showing temperatures in the low to
mid 90s and dewpoints in the mid 70s. Despite there being an influx
of cloud debris from the north, expect both of these values to
increase a few more degrees this afternoon, yielding heat index
values of 108+ degrees. This is especially true for areas along the
coastal corridor, where dewpoints are expected to surge in the wake
of an advancing sea breeze, which may produce isolated heat index
values of 112+ degrees. Nonetheless, believe the duration of these
should remain limited enough to forgo upgrading to an Extreme Heat
Warning at this time. So, will continue to carry the area wide Heat
Advisory through 7 PM.

Wednesday: A strong mid-level ridge will prevail over the Rockies
and Plains, with the eastern periphery building into the
southeastern states. At the surface, weak high pressure will develop
over the southeast. Between the ridging aloft and the weak high
pressure at the surface, temperatures will soar into the mid to
upper 90s. Dew points during this time will also rise into the mid
to upper 70s, with the highest values along the coastal corridor
behind the sea breeze. This set up will yield heat index values in
the 105-112 range, with a few pockets of 112+ degrees. One
complicating factor though, will be the chances for afternoon
convection as models still differ regarding the degree of coverage.
The current forecast features PoPs in the 25-50% range, however, if
this trends wetter, our actual temperature/dewpoint/heat index
values could run lower than forecast. Thus, after collaboration with
neighbors, have decided issue a Heat Advisory for portions of our
area, which will be in effect from 11 AM to 7 PM. Will continue to
monitor trends in the event that an upgrade along the coast is
needed.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TAFs: Southwesterly winds continue to prevail across the region,
with direction expected to shift more southerly in the wake of an
advancing see breeze this afternoon. Gusts up to 20 kts will be
possible along and behind this boundary. In regard to precipitation,
should see largely dry conditions continue through the afternoon,
with isolated storms then possible across the Charleston Tri-County
area later this evening. While brief flight restrictions at
KCHS/KJZI are possible, overall confidence still remains too low to
include any mention in this TAF issuance.

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

&&

.MARINE...
Through Tonight: A weak front will approach the region this
afternoon, yielding an increase in both winds and seas this evening
into tonight. A Small Craft Advisory will be in effect for the
Charleston County nearshore waters and the 20 to 60 nm offshore GA
waters. Conditions within the Charleston Harbor will need to be
monitored for a possible short-duration Small Craft Advisory as
gusts could approach 25 knots this evening.

Wednesday through Sunday: Winds and seas will decrease Wednesday
morning to below Small Craft Advisory criteria. Southeasterly flow
will dominate across the marine waters through the weekend, with
gusts topping out around 10 to 15 knots through Friday. Gusts are
forecast to shift to the SW and increase to 15 to 20 knots this
weekend as a cold front approaches the region. Wave heights may
range from 2-4 ft on Wednesday, decreasing to around 2 ft on
Thursday through the rest of the week.

&&

.CLIMATE...

Record High Minimum Temperatures:

July 28:
KCHS: 80/2025

July 29:
KCHS: 80/2016
KSAV: 82/1878

August 1:
KSAV: 79/2020

August 2:
KCHS: 79/2022

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory until 8 PM EDT this evening for GAZ087-088-
     099>101-114-115-137-216>219-238>241.
     Heat Advisory from 11 AM to 8 PM EDT Wednesday for GAZ099>101-
     114-115-137-216>219-238>241.
SC...Heat Advisory until 8 PM EDT this evening for SCZ040-042>045-
     147>152.
     Heat Advisory from 11 AM to 8 PM EDT Wednesday for SCZ147>152.
MARINE...Small Craft Advisory from 6 PM this evening to 8 AM EDT
     Wednesday for AMZ360-384.

&&

$$

NED/SST