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000
FXUS62 KCHS 261008
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
608 AM EDT Fri Apr 26 2024

.SYNOPSIS...
High pressure will prevail through much of next week. A weak
cold front could approach late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Despite some observations sites reporting low vsbys, the fog
remains fairly shallow and patchy. Any fog and stratus should
begin to mix out after sunrise. Overall, only minor changes
were needed for the sunrise update.

Today: Surface high pressure nosing south will become better
established across the Southeast U.S. today high amplitude
subtropical ridging builds aloft. An area of mixed stratus and
stratocumulus will build southwest into parts of the Charleston
Tri-County and far interior Southeast South Carolina prior to
daybreak. Much of this cloud cover should steadily mix out and
lift into a modest cumulus field once the sun rises and surface
heating commences. Expect partly cloudy skies to prevail for
much of the day. Highs will run a tad cooler than Thursday with
1000-850 hPa thicknesses progged to peak about 10 m lower during
peak heating. This coupled with a stronger inland push to the
afternoon sea breeze should limit highs to the upper 70s/lower
80s inland with cooler conditions closer to the coast and on the
beaches. Gusty winds will also occur near/behind the sea breeze
with gusts as high as 25 mph possible.

Tonight: The synoptic pattern will change little tonight with
sprawling 1035 hPa high pressure extending south over the
Southeast States and strong subtropical ridging aloft. A fairly
tight surface pressure gradient associated with the high itself
will hold through the night which should keep the atmosphere
somewhat mixed through daybreak Saturday. Onshore winds will
likely keep some degree of marine-based stratocumulus moving
onshore, but models appear to be struggling a bit on exactly how
much cloud cover will occur. Partly cloudy conditions were
favored, but adjustments to this will likely be needed as cloud
trends become a bit more apparent. Low will range from the upper
50s well inland to the upper 60s at the beaches. A few beach
spots along the Georgia coast, such as Tybee Island, may not
drop below 70.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
A strong upper ridge axis will remain directly over the area
Saturday into Sunday while cool surface high pressure remains to
the north. Weak ENE to E winds will prevail through the weekend.
Low-level onshore flow is expected to bring enough moisture into
the area to allow scattered to broken stratocumulus to develop
during peak heating hours. High temps both days will be in the
upper 70s to around 80.

The deep layered ridge shifts off the coast by Monday, with a
southerly flow setting up in low levels. Less cumulus
development expected on Monday, and warm advection will push
highs into the low to mid 80s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Mainly dry weather expected through the extended as a zonal flow
develops aloft and surface high pressure remains over the
western Atlantic. Warm advection and ample sunshine will yield a
warming trend with highs back in the upper 80s to lower 90s by
mid to late week.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
26/12z TAF Discussion:
KCHS/KJZI: Cigs ended up being a tad lower than expected and
solidly in IFR. The cloud layer is pretty shallow and should mix
out as sunrise approaches. Expect VFR by 14z and will persist
through 12z Saturday morning. Gusty winds with gusts 20-22 kt
will impact both terminals as the sea breeze moves inland this
afternoon.

KSAV: VFR through 267/16z Saturday. Shallow fog will mix out
quickly after sunrise. No issues are expected. A scattered cloud
deck around 1200 ft could ooze into the terminal near sunrise,
but will mix out. Wind gusts near 20 kt will be common this
afternoon as the sea breeze moves inland.

Extended Aviation Outlook: Prevailing VFR.

&&

.MARINE...
Today: Easterly winds will slowly build through the day as high
pressure noses in from the north. Winds will reach 15-20 kt in
the South Santee-Edisto Beach nearshore leg out 20 NM with
slightly lower winds expected elsewhere across the local marine
area. A robust sea breeze appears likely in the Charleston
Harbor this afternoon. Winds should peak in the 15-20 kt range
with waves building 1-2 ft. It will be close to Small Craft
Advisory levels (Charleston Harbor criteria is sustained 20 kt
or frequent gusts to 25 kt), but it appears that both sustained
wind and wind gusts will fall just shy of advisory thresholds.
Seas will average 2-4 ft.

Tonight: East winds around 15 kt will hold through the night.
Sea breeze enhancements in the Charleston Harbor will diminish
early in the evening. Seas will build to 3-5 ft and possibly as
high as 6 ft in the Georgia offshore leg out 20-60 NM. There is
some uncertainty if 6 ft seas will reach the Georgia offshore
waters by sunrise Saturday with the latest NWPS and WaveWatch
showing slight timing differences on the arrival of 6 ft seas. A
Small Craft Advisory will not be issued just yet given these
timing differences. The need for an advisory will be reconsidered
later today.

Saturday through Tuesday: Fairly long ENE fetch may bring some
6 ft seas into the offshore GA waters late tonight or Saturday
morning, then continuing into Sunday before dropping back below
6 ft. A short-duration Small Craft Advisory may be needed.
Otherwise, marine conditions will remain fairly quiet with E
winds this weekend becoming SE early next week, then S by mid
next week.

Rip Currents: Moderate onshore winds will continue through
the weekend, while approximately 3 ft waves every 6-7 seconds
hit the beaches. Local rip current calculator indicates low risk
for Saturday, but the Rip Current MOS shows Moderate for the GA
beaches, so we are carrying Low for SC and Moderate for GA.

&&

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

&&

$$