912
FXUS62 KCHS 011741
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1241 PM EST Mon Dec 1 2025

.SYNOPSIS...
A storm system will pass through the region late today into
Tuesday. High pressure then returns for the middle of this week
before the next frontal system impacts the area Friday into the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
A wedge of high pressure will persist over the area through today
and into tonight. Meanwhile, surface low pressure is expected
to organize over the Gulf, before lifting into the region later
tonight. Aloft, the forecast area will be under southwest flow
ahead of the main trough axis, with shortwave energy poised to
pass overhead. PWats will surge, likely peaking over 1.5 inches
late tonight which is 2-3 standard deviations above climatology
per NAEFS ESAT. The remainder of the daylight hours will be
dry, then light to moderate rainfall should overspread the area,
especially after midnight, as isentropic ascent increases and
forcing becomes maximized. Coverage should be fairly widespread
as we approach daybreak Tuesday. Totals through 7 AM should
largely fall in the 0.25-0.50 inch range. No flooding concern as
rain rates will not be that high - latest HREF guidance
continues to indicate 0.10-0.25" per hour at best. This rainfall
should be very beneficial given the ongoing drought over much
of the area. Low temperatures will range from the low 40s inland
to low 50s at the immediate coast.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: Aloft, a trough extending across the Great Lakes to the
Deep South will advance east, likely reaching the Atlantic Seaboard
by late day/early evening. At the sfc, low pressure developing and
positioned near a front in the northern Gulf is anticipated to track
east-northeast across the region, encountering a CAD prior to
shifting off the coast late day. Strong isentropic lift and deep
moisture (PWATs near 1.7 inches) running over the CAD in addition to
forcing associated with a strong h25 jet core, h5 vort energy and a
passing front will continue to favor numerous/widespread rain and
shower activity across Southeast Georgia and Southeast South
Carolina during morning into afternoon hours, with weak instability
also suggesting a few rumbles of thunder being possible, although
primarily well south and near the Southeast Georgia coast where sfc
temps are warmest.

The bulk of guidance suggests greatest rainfall amounts occur well
inland, generally around an inch along a stretch from Tattnall
County, GA and north-northeast to Berkeley County. Closer to the
coast, additional rainfall amounts around 0.5 inch are forecast
during morning into early afternoon hours, implying greatest forcing
and perhaps low pressure track to occur inland while the CAD holds
in place. Regardless of low track, these rains should be quite
beneficial to the region given ongoing drought conditions, while
lower rainfall rates also limit concern for flooding. The exception
could be with the early morning high tide cycle along the Southeast
South Carolina coast should rainfall occur during elevated tide
levels (see Coastal Flooding section below).

The local area will likely experience a wide range of temps given
the setup. For locations well inland, widespread clouds and
rain/showers could limit afternoon highs to the mid-upper 50s.
Closer to the coast, sfc winds have a greater chance of becoming
southerly in advance of the front, allowing afternoon highs to peak
in the mid 60s along coastal South Carolina to upper 60s/around 70
along coastal Georgia and perhaps south of I-16 across Southeast
Georgia. Dry and cooler high pressure builds across the region
during the night post fropa, favoring lows in the mid 30s inland to
low-mid 40s near the coast.

Wednesday and Thursday: High pressure centered across the Ohio River
Valley will spread across the Mid-Atlantic and Southeast states mid-
week, favoring dry and cooler conditions across the local area
Wednesday, prior to weak airmass modification on Thursday. In
general, high temps should range between the mid-upper 50s with a
few temps around 60 degrees across Southeast Georgia Wednesday
afternoon, followed by highs in the upper 50s inland to low-mid 60s
closer to the coast Thursday afternoon. Lows could reach the
freezing mark well inland Wednesday night (lower 30s), but stay
warmer along the coast (low-mid 40s).


&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Aloft, the local area should remain under a mostly zonal flow
between a broad trough extending across the northern United States
and a broad ridge across the Gulf and Atlantic. At the sfc, another
low pressure system develops across the northern Gulf, although
appears weaker and more progressive late week, suggesting a lighter
and slightly shorter rainfall event compared to early week, but
still sufficient to produce numerous to widespread rain/showers
Friday afternoon/evening and possibly through Saturday morning,
before the system and/or front shifts offshore late day. Dry high
pressure returns post fropa Sunday, with highs remaining below
normal, generally in the upper 50s inland to lower 60s across
coastal areas.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Deteriorating conditions are expected at all terminals through the
TAF period. Ceilings will lower to MVFR this afternoon and
evening, before eventually becoming widespread IFR overnight,
likely within a couple of hours of midnight. Reductions in
visibility are also likely as light to moderate rain overspreads
the area. IFR conditions is expected to persist through the end
of the period/18z Tuesday.

There also remains a concern for LLWS early Tuesday morning. Model
soundings indicate around 40-45 knots at 2kft, so LLWS has been
maintained in the TAF for all terminals.

Extended Aviation Outlook: Flight restrictions are likely at
CHS/JZI/SAV Tuesday for low ceilings and vsbys associated with
rain/showers and possibly isolated thunderstorms as a front/low
pressure system tracks across the region. VFR conditions return
at all terminals Wednesday and Thursday with high pressure
dominating the weather pattern, before chances for flight
restrictions return at all terminals with the next front/low
pressure system bringing rain and/or showers to all terminals
Friday.

&&

.MARINE...
Through Tonight: A wedge of high pressure should weaken tonight as
an area of low pressure moves over the region. This will allow
northeast winds initially to become southerly late tonight. Gusts in
the low 20 kt range this afternoon will briefly come down later this
evening, before beginning to ramp back up near daybreak. Wave
heights will also increase late tonight, with 6 ft seas developing
over the SC nearshore and outer GA waters during the pre-dawn hours.
The wind and sea conditions will be highlighted with Small Craft
Advisories for these zones.

A low pressure system will approach local waters from the west-
southwest on Tuesday with a CAD slow to weaken and resulting in a
slightly pinched gradient. Southerly winds gusting up to 25-30 kt
outside the Charleston Harbor and beyond Georgia nearshore waters
are possible. Seas should also build up to 6-8 ft during this
timeframe, supporting the continuation of Small Craft Advisories
across nearshore SC waters and outer Georgia waters late day into
the evening on Tuesday. Winds will remain mostly offshore and weaken
heading into Wednesday as high pressure spreads across the region.
Expect winds/seas to remain well below Small Craft Advisory
thresholds through late week, with only a slight uptick in winds and
seas associated with the arrival of the next low pressure
system.

&&

.TIDES/COASTAL FLOODING...
The first tide of concern this week will be the early morning
high tide Tuesday, occurring around 5 AM in the Charleston
Harbor. Latest indications are that tide levels should peak in
the 7.0-7.2 ft MLLW range, which is above the minor coastal
flood threshold. A Coastal Flood Advisory could be needed. From
Beaufort county south across the Georgia coast, no issues are
expected.

Astronomical tides will then continue to rise with the morning
high tide cycles through Friday and remain elevated through the
weekend. Coastal Flood Advisories will likely be needed for
morning high tide cycles, primarily at Charleston Harbor
(Charleston and Coastal Colleton counties) through late week.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 4 AM Tuesday to 1 AM EST Wednesday
     for AMZ350-374.
     Small Craft Advisory from 10 AM to 7 PM EST Tuesday for AMZ352.

&&

$$

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