290
FXUS62 KCHS 181911
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
311 PM EDT Fri Apr 18 2025

.SYNOPSIS...
High pressure will persist into early next week. A front could
push into the region by the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Surface high pressure off the coast of NC/VA will continue to slowly
move eastwards, with upper level ridging strengthening into the
overnight period. This will continue the observed quiet and warm
conditions, with afternoon highs still expected to reach up into the
lower to mid 80s inland, with areas along the coast in the mid to
upper 70s. The breezy winds behind the sea-breeze will be subsiding
near-sunset, along with the cu field dissipating around the same
time.

As the inversion sets up during the evening hours, the region
becomes decoupled allowing for winds to further decrease into the
overnight hours. With clear skies, radiational cooling will allow
for temperatures to drop down to near dewpoint temperatures, in the
mid 50s inland and lower 60s along the coast. Similar to the past
couple mornings, some patchy fog in low-lying areas near sunrise is
possible (up to 20% probability) highest across inland southeastern
Georgia counties. Due to the patchy nature and low probabilities,
have left mention out of the forecast.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
An impressive deep-layered subtropical anticyclone will extend
across the Southeast U.S. for much of the period, slowly sliding
offshore by Monday. This will result in a regime dominated by strong
synoptic scale subsidence which is well represented by strong
capping inversions noted on regional model soundings. With the
center of the Bermuda high progged to remain well offshore, expect
modest to locally strong resultant sea breeze circulations to form
each afternoon and move steadily inland before decaying during the
early evening hours while exiting into the Midlands, CSRA and east-
central Georgia. Highs each afternoon will range from the mid-upper
80s inland with lower 70s at the beaches. Lows both Sunday and
Monday mornings were trended slightly cooler than the 18/13z NBM
guidance with full boundary layer decoupling likely to occur each
night away from the coast. Lows will range from the the upper
50s/lower 60s with upper 60s at the beaches and Downtown Charleston.
Varying degrees of high clouds will stream across the region,
especially Sunday into Monday. Some shallow cumulus humilis is also
possible each afternoon ahead of the sea breeze.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure off the Southeast U.S. will gradually weaken into the
middle of next week as the subtropical anticyclone aloft begins to
breakdown and the resulting flow across the southern states becomes
more zonal. A cold front will attempt to drop into the region
Wednesday. It is unclear how far south the front will get given the
boundary will become increasingly parallel with the flow aloft. Rain
chances will build by mid-week as the front draws closer with
signals that there may be some sea breeze/frontal interactions. Pops
were increased to 20-40% based on the latest NBM, but again, much
depends on how far south the front gets before retreating back to
the north Thursday into Friday. Above normal temperatures will
persist.


&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
The sea-breeze is pushing inland, with semi-breezy winds behind
it gusting into the teens to lower 20s. Otherwise, VFR and
quiet conditions are expected to continue into the overnight
period. Similar to the past couple mornings, some patchy fog in
low-lying areas near sunrise is possible (up to 20%) highest
across inland southeastern Georgia counties, not looking to
impact the TAF sites at this times.

Extended Aviation Outlook: Gusty winds are possible each afternoon
at all terminals with the passage of the sea breeze. There are no
other concerns.

&&

.MARINE...
Tonight: Surface high pressure off the coast of NC/VA will
continue to keep conditions mostly quiet across the region, with
winds remaining out of the southeast. The wind will remain on
the semi- breezy side with gusts into the teens, possibly lower
20s as evident by Shutes Folly and Beaufort obs, through the
early overnight hours but should remain below small craft
criteria. The winds will subside after midnight into the morning
hours on Saturday.

Saturday through Wednesday: A southerly flow regime with afternoon
sea breeze enhancements in the Charleston Harbor and along the
land/sea interface will persist into the middle of next week. Winds
will generally remain less than 15 kt with seas 2-4 ft.

&&

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

&&

$$

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