720
FXUS62 KCHS 122000
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
400 PM EDT Wed Jun 12 2024

.SYNOPSIS...
A stationary front will meander near or just off the coast
through the end of the week. High pressure will build in from
the north through the weekend, then shift east early next week.

&&

.NEAR TERM /TONIGHT/...
Surface low clearly distinguishable on vis satellite imagery
near Orlando, FL this afternoon will slide off the SE coast
where coastal troughing persists overnight. CWA will remain on
the "dry" side of sharp low level moisture gradient along the
coastal trough axis overnight, keeping a rain-free forecast in
place through sunrise, as showers are expected to remain
offshore. Mid to upper level clouds associated with height falls
ahead of a weak trough/low aloft will stream over the area
through the night, abating radiational cooling and, along with a
persistent weak gradient overnight, precluding any significant
fog threat. Lows will be within a few degrees of normal...upper
60s to lower 70s for most.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Thursday and Friday: Aloft, h5 shortwave energy embedded in a weak
longwave trough will slowly shift across the Southeast United States
while a large ridge centered across the Central United States
strengthens and expands east toward the area through early weekend.
At the sfc, a nearly stationary front will linger well offshore,
becoming a focusing mechanism of low pressure attempting to develop
beyond the Gulf Stream while slowly drifting further offshore. The
pattern will support gradually warming conditions late week as the
ridge nudges across the area and ample sfc heating takes place. A
few showers and/or thunderstorms will also be possible across
coastal counties, where low-lvl moisture lingers and perhaps
strongest convergence occurs near the land/water interface. High
temps will range in the upper 80s/lower 90s Thursday, then low-mid
90s Friday away from the immediate coast. Overnight lows will also
remain mild, generally in the upper 60s to lower 70s Thursday night,
then lower to middle 70s Friday night.

Saturday: Any area of low pressure offshore becomes more diffuse
and/or shifts to the northeast away from the region in advance of a
cold front approaching the local area from the west-northwest during
the day. Aloft, a large/expansive ridge will become directly
centered across the Southeast United States while a weak downslope
flow aloft takes place. Strong subsidence associated with these
features will help keep fropa dry and mix out sfc dewpts into the
mid-upper 60s for areas away from the coast heading into peak
diurnal heating. Strong sfc heating under mostly sunny skies along
with compressional heating associated with the arriving front will
support the warmest temps of the week. 1000-850 mb thickness values
suggest high temps in the mid-upper 90s across most areas away from
the coast, and even a few locations touching 100 degrees well inland
across southeast Georgia and southeast South Carolina. These temps
along with mid-upper 60 sfc dewpts support heat index values ranging
between 100-105 degrees, falling just shy of Heat Advisory criteria.
However, a sea breeze circulation shifting inland could temporarily
nudge dewpt/humidity levels higher during peak heating and will need
to be closely monitored for potential Heat Advisory conditions.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A deep layered ridge across the Southeastern U.S. will prevail
through early next week. Surface high pressure will set up across
the Northeast, resulting in return flow helping to wrap the deeper
Gulf moisture around the backside of the high and into the Deep
South. The advection of moisture/instability will support scattered
showers and thunderstorms early next week, mainly during the
afternoon and evening hours when the sea breeze is active.
Temperatures should begin to slightly decrease and trend toward near
normal or slightly above normal.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR prevails at all terminals through the TAF period. More
robust low level moisture could make a push toward the coast
around daybreak Monday morning as low pressure develops within
coastal troughing off the Southeast coast, but any sub-VFR
ceilings are unlikely to progress any further inland than the
beaches through at least the morning hours. Scattered mid and
high clouds overnight preclude any significant fog threat, with
gusty E winds this afternoon diminishing as the sea breeze
circulation fades this evening.

Extended Aviation Outlook: Prevailing VFR conditions are expected at
CHS/JZI/SAV terminals through Saturday, although brief flight
restrictions can not be ruled out for an afternoon shower or
thunderstorm each day. Tempo flight restriction chances increase
Sunday with greater coverage of showers/thunderstorms near a front
departing the area to the south, followed brief flight restriction
possibilities on Monday with afternoon showers/thunderstorms.

&&

.MARINE...
Tonight: Breezy conditions near the coast this afternoon will
diminish as the sea breeze circulation weakens early this
evening. Moderate northeast winds then prevail tonight as low
pressure begins to gradually deepen off the Southeast coast.
Isolated showers and thunderstorms may develop over the coastal
waters late tonight. Seas increase a bit to 2-4 ft overnight
with increasing ENE windswell, with an underlying modest medium
period S to SE swell continuing as well.

Thursday through Monday: Conditions are expected to remain below
Small Craft Advisory levels as sfc high pressure extends across the
region from the north while a nearly stationary front becomes the
focusing mechanism of a more enhanced coastal trough and/or area of
low pressure developing further offshore by the weekend. In general,
northeast winds around 15 kt will become more southerly around 10 kt
or less as the coastal trough/low drifts further offshore and/or to
the northeast and away from the region well ahead of a front
approaching from the west-northwest during the weekend. The arriving
front will be slow to shift south of the area early next week while
high pressure spreads across coastal waters in its wake. East-
northeast winds around 15 kt should return across most waters behind
the front. Seas should average between 2-4 ft late week into early
next week.

&&

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

&&

$$

NEAR TERM...CEB
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...CEB/DPB
MARINE...CEB/DPB