400
FXUS62 KCHS 151120
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
720 AM EDT Sun Jun 15 2025

.SYNOPSIS...
Atlantic high pressure will continue to build across the
Southeast United States into next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Little change in the large scale pattern from the past
few days. The area will remain between a deep layer, broad
trough to the west over the middle MS and TN valleys and deep
layer ridging to the southeast over the Atlantic. Water vapor
imagery shows an upper level disturbance associated with dying
convection over northern GA, and another further west over
southern TN and northern AL. The remnants of these disturbances
should move just north of the region today, but could help to
provide a little extra upper level lift. This lift, ample deep
layer moisture, and mean CAPE of 1500-2000 J/Kg will again
result in scattered to numerous showers and thunderstorms from
late morning through the afternoon. Hi-res models again
indicating that the highest convective coverage will generally
occur over the eastern 1/3 of the area, within the low level
confluence area between southwest flow and more south-southwest
flow near the coast. Given relatively low convective
temperatures in the upper 80s, convection may again start a
little earlier than climatology would predict. Also, with PWs
again 2+ inches, and the confluent low level flow over the
eastern portion of the area, there is a chance for locally heavy
rainfall and minor flooding. High temperatures in the upper 80s
to the lower 90s.

Tonight: Convection is expected to decrease during the evening.
Mostly cloudy skies in the evening, becoming partly cloudy
late. Lows in the lower 70s, except mid 70s close to the coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Chances for daily showers and thunderstorms continue into the week
as a surface high pressure over the Atlantic remains off to our
east, and the region remains sandwiched between an upper level
high off to our south-southeast and broad troughing across the
Ohio River Valley. The lack of strong forcing and weak winds
aloft will keep chances for severe weather on the low side
(<5%), while the presence of 1-2 kJ of MUCAPE is responsible for
the non-zero chances. Highest probabilities and spatial
coverage for showers and thunderstorms are expected during the
afternoon hours when instability is highest, and decreasing into
the evening and overnight hours as instability wanes. With
precipitable water remaining above 1.75", locally heavy rainfall
can`t be ruled out.

As for temperatures, expect them to slowly increase into the middle
of the week given the persistent pattern underneath the
aforementioned upper level high. NAEFs and ECMWF ensemble
situational awareness tables (ESATs) continue to show the region
remaining near/above the 90th percentile of climatology with respect
to geopotential heights from 850mb up to 200 mb, resulting in
afternoon highs in the lower to mid 90s on each day, while those
near the coast remain in the mid/upper 80s. Heat index values in the
mid 90s to lower 100s are also expected, possibly as high as mid to
upper 100s if higher dewpoints in the upper 70s are realized. Best
chances appear to be on Wednesday as that is when highest
temperatures are possible due to the ridge building aloft.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The aforementioned pattern continues while the upper level
ridge begins to slowly build/shift westward as a weak trough
moves into the northeast Thursday into Friday. Temperatures
remain largely in the lower to mid 90s, with daily chances for
showers and thunderstorms continuing.

Behind the exiting upper level trough, deterministic and ensemble
models show a ridge building aloft as it moves westwards towards the
east coast. At the surface, some guidance continues to show a weak
front and low pressure move down from the Ohio River Valley, though
the majority of guidance does not include that feature...however,
this mismatch is leading to NBM temperatures coming in a touch
cooler than expected. Would not be surprised to see later runs of
the NBM bring temperatures closer to the mid to upper 90s over the
weekend, closer to what the 90th percentile is showing.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Today and Tonight: VFR conditions for all TAF sites through
this morning. Scattered to numerous showers and thunderstorms
roughly between 15-22Z could result in brief flight
restrictions, with MVFR CIGS. Latest guidance is trending toward
slightly lower chances for convection today. Therefore, have
kept Prob30 mention instead of Tempo for afternoon convection. Any
convection should dissipate after sunset, with return to VFR
conditions after 00Z Mon.

Extended Aviation Forecast: Brief flight restrictions are possible
in showers and thunderstorms each day, mainly in the afternoon.

&&

.MARINE...
Today and Tonight: No highlights are expected for this period.
The waters will remain between deep layer ridging to the
southeast and a broad trough well to the west. This will
continue southwest winds of 10-15 knots. Winds could gust up to
near 20 knots near the mouth of Charleston Harbor this
afternoon. Seas 2 to 4 feet, highest beyond 10 nm offshore.There
will also continue to be a longer period swell from the
southeast.

Monday through Friday: Typical summertime conditions will prevail
over the waters with high pressure centered offshore of the
Southeast States. A broad, southerly wind regime can be expected
with winds generally averaging 15 kt or less, except a bit higher
along the land/sea interface and Charleston Harbor each afternoon
with the sea breeze. Seas will remain 4 ft or less through the
period.

Rip Currents: An easterly swell surge will arrive along the
Charleston County beaches today and all remaining beaches for
Monday. This coupled with locally breezy conditions near the
afternoon sea breeze will support a moderate rip current risk for
all beaches today and Monday.

&&

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

&&

$$

NEAR TERM...RFM
SHORT TERM...APT
LONG TERM...APT
AVIATION...RFM
MARINE...APT/RFM