845
FXUS62 KCHS 230804
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
404 AM EDT Fri May 23 2025

.SYNOPSIS...
High pressure will prevail through tonight. A weak front to the
south slides closer to the area and stalls through the holiday
weekend. This front eventually lifts north early next week as
an cold front brings increasingly unsettled weather later
Monday through Tuesday. Mainly seasonable conditions return by
later next week with weak troughing stretching across the
Southeast.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, a large mid-lvl trough extending across much of the
Mid-Atlantic and Northeast will gradually flatten while slowly
shifting off the Eastern Seaboard as weak/broad ridging takes place
across the Great Plains. The pattern will setup a zonal flow across
the Southeast, favoring a dry west-northwest downslope wind across
the local area while sfc high pressure spreads across the region
behind a front well to the south and offshore. Latest model
soundings indicate substantial dry air throughout the day,
suggesting any h5 shortwave energy left rounding the departing
trough aloft to struggle producing nothing more than a few clouds
across the local area this afternoon. Ample sunshine, the dry
downslope flow and 1000-850 mb thickness values suggest highs in the
mid 80s across Southeast South Carolina and upper 80s to around 90
degrees across Southeast Georgia, warmest south of I-16.

Tonight: High pressure centered across the Mid-Atlantic states will
nudge into the area during overnight hours, continuing a dry pattern
through the night. Winds are expected to decouple early, leading to
light and/or calm winds away from coastal locations for much of the
night. This will lead to a favorable radiational cooling setup and
low temps that are slightly cooler than previous nights. In general,
lows should dip into the upper 50s across the far interior and
northern areas in the Francis Marion Forest, but should remain in
the mid-upper 60s closer to the coast, and around 70 degrees at the
beaches.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
The area remains within broad upper troughing as a large cutoff low
lingers over eastern Canada this weekend. Deep layer westerly/downsloping
flow and subsidence keeps a mainly dry forecast in place Saturday,
though a very weak front stalled across SE GA could provide for
just enough moisture pooling to spawn an afternoon shower or two.
Seasonable temps expected.

Later Saturday night into Sunday will begin an increasingly
unsettled period as a weak upper wave moves overhead. A few coastal
showers/storms expected Sunday morning as DPVA initiates broad/weak
lift locally, with convective activity increasing by the afternoon
along and ahead of the sea breeze. The aforementioned weak front
remains stalled over/near SE GA, and could bring some moisture
pooling/modest convective enhancement north of and along the front,
resulting in slightly greater shower/storm coverage expected across
the Lowcountry and Savannah River area. Moderate storm motion and
lack of substantial shear keeps the overall severe and flooding
threat low, but a few back-building storms producing localized heavy
rainfall and a wet microburst or two are possible. Otherwise, temps
climb a few degrees above normal Sunday afternoon away from the
early afternoon storms, with the potential for a few locations
across SE GA (south of the weak front) to reach into the mid-90s.

Expect mainly diurnally-driven shower/storm coverage to increase
Monday as a shortwave begins to approach from the west. Overall
heavy rainfall and severe weather threat is limited by lack of shear
and moderate storm motions again on Monday, though the front
remaining nearby could result in some focus for storm activity and
potential for training again.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Shortwave passes overhead Tuesday. Convective threats require
further monitoring as the wave could bring modest shear enhancement
and some marginally organized convection is possible ahead of an
approaching cold front. PWAT values reach their peak of near 2
inches later in the day Tuesday, and locally heavy rainfall is again
possible.

Wednesday begins the trend back toward seasonable convective
patterns with scattered afternoon convection expected. Post-frontal
CAA is minimal (as is standard this time of year), with weak
troughing over the Southeast likely to bring continued seasonable
conditions through the end of the workweek.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 06Z
Saturday. However, a few wind gusts up to 15-20 kt are possible
at CHS/JZI terminals mid afternoon today.

Extended Aviation Outlook: Threat for flight restrictions
primarily limited to convection, mainly following a diurnal
trend with increasing coverage Sunday through Tuesday.

&&

.MARINE...
Today and Tonight: Offshore flow will prevail this morning with high
pressure spreading across the region behind a cold front well
offshore and south of the region. In general, west winds should be
no higher than 10-15 kt. By the afternoon, sfc winds should become
more southwest across nearshore South Carolina waters along the
Charleston County Coast and in the Charleston Harbor, while turning
more east or southeast across remaining waters as a weak sea breeze
takes shape along the coast. A few gusts to 20 kt are possible along
the Charleston County Coast and in the Charleston Harbor as the sea
breeze begins to shift inland this afternoon. High pressure centered
north of the region will continue to nudge across local waters
tonight, leading to somewhat lighter offshore winds from the west or
northwest by around midnight. Seas will generally range between 1-2
ft, although seas could touch 3 ft across far outer Georgia waters
this morning.

No significant marine concerns through the holiday weekend and into
next week with mainly moderate winds prevailing, and gusty winds
developing nearshore with the sea breeze each afternoon.

One note to boaters: Stronger than normal currents can be expected
on tidal waterways through the holiday weekend given large tidal
ranges as we approach the Perigee on Monday. Early afternoon low
tides will be followed by quickly rising water, which has, in the
past, resulted in dangerous conditions as area sandbars quickly
become submerged.

Rip Currents: The risk for rip currents near Savannah/Tybee Island
were borderline Moderate for Saturday. Given it`s a holiday weekend,
have opted to maintain a Moderate Risk for rip currents along Georgia
beaches Saturday.

&&

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

&&

$$

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