North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

230
FXUS62 KCHS 271127
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
727 AM EDT Wed May 27 2026

.WHAT HAS CHANGED...
Aviation section updated for the 12Z TAFs.

&&

.KEY MESSAGES...
- 1) Hot and humid conditions with periods of showers and thunderstorms
  across SE GA/SC today and Wednesday. Locally heavy downpours
  are possible.

- 2) An unsettled wet pattern is expected to develop
Friday into the weekend, increasing the potential for heavy rainfall
and localized flooding.

&&

.DISCUSSION...
KEY MESSAGE 1: Hot and humid conditions with periods of showers and
thunderstorms across SE GA/SC today and Wednesday. Locally heavy
downpours are possible.

Early this morning, satellite water vapor and RAP40 indicated a mid-
level vort max near KJAX, drifting to the north. This feature was
aiding in the formation of a band of showers and thunderstorms
across inland GA this morning. Based on radar trends and recent runs
of the HRRR, the showers will develop to the east on an old outflow
boundary. MLCAPE is forecast to remain around 1000 J/kg, the
forecast will mention thunderstorms.

NAM indicates the H5 heights across the forecast area will gradually
decrease through today as a trough ripples over the lower
Mississippi Valley. Mild llvl thicknesses and partly sunny
conditions should allow temperatures to warm steadily through early
this afternoon. Using a blend of MOS, high temperatures are forecast
to range from around 90 along the coast with upper 80s inland. In
addition, sfc dewpoints are forecast to range in the low to mid 70s
this afternoon. The combination of the above normal temperatures and
warm dewpoints may yield heat index values above 100 degrees across
portions of the coastal counties of SE GA/SC this afternoon.

As temperatures warm, a sea breeze will push inland this afternoon
and evening. Recent runs of the HRRR has trended lower with
thunderstorm coverage this afternoon, however, it seems a bit
overactive with convection this morning. Forecast soundings indicate
a weaker subsidence inversion across the coastal counties this
afternoon. Hot and humid conditions should support a broad field of
1500-2000 J/kg across the region this afternoon. Following the 0Z
HREF and REFS, scattered to numerous showers and thunderstorms
should develop along the sea breeze during the mid to late afternoon
hours. PW values are forecast to range between 1.9" to 2" with WBZ
around 12 kft. This environment should support efficient rainfall
producing thunderstorms, primarily along and inland of the sea
breeze. HREF probs indicate a 50-70% for 1"/3hr and 10% for 3"/3hr
rainfall rates. Thunderstorm activity may remain a bit closer to the
coastal counties, compared to the past couple of days. It is
possible that a Flood Advisory or two could be issued late this
afternoon, potentially over the inland I-16 and I-26 corridors. Deep
convection should wane during the evening hours.

Thursday, conditions appear very comparable to today. Humidity may
range a bit higher as the upper ridge continues to weaken and area
of rain soaked ground increases. Given high temperatures in upper
80s to around 90 and dewpoints in the low to mid 70s, conditions
will remain hot and humid. Coastal counties may see heat index
values between 100 to 103 degrees. Storm coverage could be a little
less on Thursday. However, the weakening ridge will allow storm
motions to approach the coast, resulting in an increase in coastal
PoPs.

KEY MESSAGE 2: An unsettled wet pattern is expected to develop
Friday into the weekend, increasing the potential for heavy rainfall
and localized flooding.

As the aforementioned front stalls across the region, chances for
rainfall will remain elevated throughout the weekend. Models
continue to show a weak surface low pressure or two may form along
the front before moving out into the Atlantic, which would bring a
period of heavier rainfall to the region. With precipitable water
values remaining near the 2 inch mark throughout the weekend and
slow storm motions of 10-15 knots, thunderstorms will be capable of
producing locally heavy rainfall.

Guidance continues to suggest widespread totals of 2 to 4 inches
over the 72 hour period from Friday through Sunday, with NBM
probabilities for 3 inches during the same period remaining in the
15 to 30% range. Breaking it down into 24 hour periods, NBM
probabilities for 2 inches remains below 20% throughout the weekend,
further reinforced by the parent ensembles themselves which show the
same. Ensemble clustering analysis reveals that the most favorable
solutions (probabilistically speaking) keep the heaviest
precipitation out of the immediate area, with the lesser likely
solution being the ones producing heavier precipitation totals
across the region. So, while the risk for higher rainfall totals (4+
inches) remains on the lower end, they are still possible, with the
details continuing to be refined as additional model runs come in.

Chances for severe weather appear to be on the lower side given the
general lack of shear, but cannot be ruled out. Depending on the
time of day, severe weather would most likely be associated with the
development of a surface low pressure, but given the lack of
agreement on if/when that may occur, confidence is generally low.

As for temperatures, there is good agreement that we`ll see a cool-
down from the current daily mid 80s to lower 90s dropping a few
degrees into the lower to mid/upper 80s Friday and Saturday. A
surface high pressure moving into the northeast pushes the front a
bit further south on Sunday, further bringing high temperatures down
into the upper 70s to lower 80s for Sunday and Monday.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Prior to the 12Z TAFs, KCLX detected a band of showers between
KSAV and Tybee Island. The KSAV TAF will be initialized with a
mention of VCSH. An approaching disturbance and deep moisture
should support rounds of MVFR ceilings over KJZI until 14Z.
This morning, KCHS and KJZI should remain VFR. However, MVFR
ceilings and showers may approach from the SW during the pre-
dawn hours, we will monitor forecast trends. Recent runs of the
HRRR, RRFS, and HREF indicates that a band of showers and
thunderstorms are expected to develop along the seabreeze just
inland of the terminals this afternoon. The convection will be
highlighted in the TAFs with TEMPOs at KCHS and KSAV between
19-23Z, and a PROB30 at KJZI between 20-23Z. Convection should
gradually dissipate this evening.

Extended Aviation Outlook: Brief flight restrictions possible within
showers and thunderstorms at CHS/JZI/SAV terminals during the
afternoon hours into the later half of the week. More periodic
flight restrictions are possible Friday into the weekend as the
potential for widespread showers/thunderstorms increases. In
addition, patchy overnight fog and/or stratus cannot be ruled out
after recent rains.

&&

.MARINE...
Today and tonight: The marine zones will remain under the influence
of broad high pressure through the period. South winds should remain
between 10 to 15 kts with some gusts into the low 20s. Wave heights
will favor values between 3-4 ft.

Thursday through Sunday: Conditions are generally forecast to remain
below Small Craft Advisory criteria into the weekend, with daily
chances for showers and thunderstorms. A surface front pushes down
into the region overnight into Friday, with a surge in winds 15 to
20 knots behind the front Friday afternoon before the front stalls.
The surface front lingers across the region throughout the weekend,
and a surface low pressure or two may form along the front, possibly
pinching the pressure gradient a couple times throughout the
weekend. This would bring brief periods periods of Small Craft
Advisory level winds and seas, though confidence in timing and
location are currently low.

Rip Currents: An elevated rip current risk will remain through the
week with a modest easterly swell around 3 to 4 feet every 8 seconds
and sea breeze influences. A moderate risk of rip currents is in
place for all area beaches through Thursday.

&&

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

&&

$$

APT/NED