Hilton Head Island, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

103
FXUS62 KCHS 290011
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
811 PM EDT Sun Jun 28 2026

.WHAT HAS CHANGED...
Key message 1 has been updated for latest trends. The Aviation
Section has been updated for the 00Z TAF issuance.

&&

.KEY MESSAGES...
- 1) A few strong to severe thunderstorms are possible this
  evening, with the primary threat area across southeast SC.

- 2) Hot and humid conditions will continue into Monday and
  another Heat Advisory may be required.

- 3) High temperatures will be slightly above normal on Tuesday,
  then gradually rising through the holiday weekend. Heat
  Advisories could be required through the holiday weekend
  across portions of the forecast area.

&&

.DISCUSSION...
KEY MESSAGE 1: A few strong to severe thunderstorms are
possible this evening, with the primary threat area across
southeast SC.

Aloft a strong 500 mb ridge is centered over the southeastern
states. Along the northern periphery of the ridging a shortwave
trough is expected to ripple eastward toward the NC/SC coastline
into this evening. An ongoing MCV will progress ESE across the
Carolinas through the remainder of today. CAMS are in decent
agreement that this feature will hold together and reach the
northern portions of the local forecast area between 8 PM and
midnight tonight. The SPC continues to highlight inland Berkeley
and Dorchester Counties with a Slight Risk for severe weather and
a Marginal Risk across remaining areas in southeast SC. This
jibes with ongoing trends, which suggest the main severe threat
to be north/inland of the local forecast area (closer to the
shortwave aloft). However, there is still a risk for a strong
and/or severe storm, mainly across the Tri-County Area this
evening. Latest mesoanalysis indicates plentiful SBCAPE on the
order of ~2000 J/kg along with 800-1000 J/kg of DCAPE. Damaging
wind gusts are the main forecast hazard with storms this
evening. Locally heavy rainfall is also possible, given PWATs
~1.9", however a progressive storm motion should limit the heavy
rainfall threat.

KEY MESSAGE 2: Hot and humid conditions will continue into Monday
and another Heat Advisory may be required.

Tonight: Overnight lows will be very mild providing little
relief from the heat, only dropping into the mid to upper 70s.
These values will challenge the record high minimums at the
local climate sites, see the Climate Section for more details.

Monday: The ridging aloft will persist into Monday, while the
surface high pressure shifts to the south and weak low pressure
develops along a stalled front off the southeastern coastline in the
vicinity of the Outer Banks, NC. Another hot day is forecast, with
temperatures reaching into the mid/upper 90s. These temperatures
combined with dewpoints in the 70s will yield heat index values in
the 103-110 range. Another Heat Advisory for portions of the
forecast area, generally along and east of I-95, is possible. A
complicating factor in regards to a potential Heat Advisory is with
the stalled front and weak low pressure off the NC coast. With these
features in the vicinity of the local forecast area an increase in
afternoon convection is forecast, with PoPs in the 30-40% range.
These showers/thunderstorms could disrupt peak heating - yielding
heat index values shy of Heat Advisory criteria. At this juncture a
Heat Advisory for Monday will not be issued and the need for a Heat
Advisory will be reassessed with future forecast updates. While
widespread severe weather is not anticipated, strong to marginally
severe storms are possible, especially along boundary
interactions.

KEY MESSAGE 3: High temperatures will be slightly above normal on
Tuesday, then gradually rising through the holiday weekend. Heat
Advisories could be required through the holiday weekend across
portions of the forecast area.

Ridging aloft will remain the dominant synoptic feature this week,
initially centered over the TN Valley on Tuesday. It will then shift
eastward towards the East Coast by the end of the week and remain in
place through the holiday weekend. The main forecast story will
continue to be the temperatures. Wednesday will feature highs
slightly above normal, with temperatures warming to above normal
into the holiday weekend. High temperatures could again reach into
the mid to upper 90s late week and into the holiday weekend, which
combined with dewpoint values in the 70s will likely yield heat
index values in the 100-110 range. Heat Advisories could be required
for portions of the forecast area at the end of the week and into
the holiday weekend.

As for the convective potential, the pattern will only support
chance POPs along our GA coast on Tuesday, then dry conditions
Wednesday and Thursday, followed by slight chance POPs for
portions of our area Friday into the holiday weekend. Even
though POPs are not very high, any convection that forms this
time of year, especially with these temperatures, will have the
potential to be strong to borderline severe, along with having
locally heavy rainfall.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR conditions should prevail at CHS/JZI/SAV terminals tonight
through late morning Monday. However, a cluster of thunderstorms
could approach CHS/JZI terminals between 01-04Z this evening, with
greatest risk for direct impacts at the CHS terminal. For now, VCTS
has been introduced at the CHS terminal between 01-330Z Monday.
Scattered showers/thunderstorms are also forecast Monday afternoon
along/ahead of a front entering the region. PROB30 -TSRA groups have
been added at CHS/JZI between 18-21Z Monday and at SAV between 19-
23Z as a result. North/northeast winds around 10 kt are likely post
fropa mid-late afternoon.

Extended Aviation Outlook: Brief flight restrictions are possible
due to showers and thunderstorms Monday afternoon and maybe Tuesday
afternoon.

&&

.MARINE...
This Evening and Overnight: Southerly winds will continue to surge
into the 15-20 kt range this evening, with a few 25 knot gusts in
the Charleston County waters during the next 1-2 hours. Overnight,
southwest flow will remain somewhat elevated through the early
morning hours. Seas are expected to be mostly 2-3 feet across
most of the waters. Slightly higher seas up to 4 feet will be
possible in the Charleston County waters this evening through
the early morning hours. Also of note, thunderstorms could
develop inland during the evening hours and impact the coast and
the coastal waters through the early morning hours with gusty
winds and lightning. The best thunderstorm coverage will be
possible across the SC waters.

Extended Marine: Expect weak winds on Monday as a front approaches
from the north. The front will move south through our area Monday
night, causing winds to shift to the NE by Tuesday morning. Then,
the synoptic pattern will generally support winds from the NE or E
through Thursday. Seas should stay 4 ft or less. No Small Craft
Advisories are expected.

&&

.CLIMATE...
Record High Temperatures:

June 28:
KCHS: 99/1998
KSAV: 100/1998

June 29:
KCHS: 99/1998
KSAV: 101/1959

July 3:
KCHS: 98/2019

July 4:
KCHS: 98/2023
KSAV: 99/1997

Record High Minimum Temperatures:

June 28:
KCHS: 78/2013
KCXM: 81/1998

June 29:
KCHS: 79/1977
KSAV: 80/1885

July 3:
KCHS: 78/2016

July 4:
KCHS: 79/2016
KSAV: 79/1931

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$