841
FXUS62 KCHS 061117
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
617 AM EST Sat Dec 6 2025

.SYNOPSIS...
A frontal system will maintain unsettled weather through early
next week, then cold high pressure will build in. A reinforcing
cold front will move through late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
At sunrise: Patches of light rain and drizzle continue to track
across the forecast area, gradually increasing in coverage as
deeper forcing arrives from the west associated with a shortwave
trough aloft. Rainfall rates will remain light, and the threat
of flooding continues to be very low.

Today: Aloft, the shortwave trough will quickly track eastward
across the Appalachians and toward the Mid Atlantic, while the
upper jet spreads across the same region. This will bring an
expanding area of right entrance region jet divergence across
the Southeast, coincident with precipitable water values in the
1.25-1.50" range. At the surface, the front will remain situated
to the south and southeast, keeping the forecast area solidly
on the cold side of the front. The increasing forcing from the
trough and jet aloft is expected to lead to an expansion of
stratiform rain across the forecast area, starting around late
morning or midday and continuing through the late afternoon
though the axis of precipitation should gradually shift to the
south. Additional rainfall amounts should mostly fall into the
0.25-0.50" range, with some potential for locally higher amounts
perhaps as high as 0.75" primarily along and south of a line
roughly from around Reidsville to Springfield to Beaufort. This
area where potentially higher amounts could occur is primarily
due to the rainfall lasting longer there as the axis of deepest
moisture shifts to the south. Another day of thick cloud cover
and persistent rainfall will result in temperatures struggling
to reach the low 50s for much of the area.

Tonight: The trough aloft will continue to dampen and quickly
eject out over the Atlantic and the forecast area will remain
under the influence of southwest flow. There is good model
agreement that the axis of deeper moisture will steadily shift
southward and additional rainfall will mostly be limited to
areas along and south of I-16 and along the GA coast through
midnight. Most of the forecast area should be dry after midnight
and additional overnight rain totals of a 0.10-0.25" should
only occur south of Savannah across the GA coast. Lows will be a
bit colder, with upper 30 occurring across the far inland tier,
ranging to the mid to upper 40s along the coast.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A series of shortwaves will move through Sunday into Monday
while a front remains stalled along the Southeast coast. Ample
moisture will exist to support occasional light to moderate rain
showers. On Sunday the best coverage and greatest rain totals
will be across southeast GA and coastal southeast SC. In our far
southern areas the total rainfall Sunday through Sunday night
could exceed 0.75" while most other areas see no more than 0.2".
The strongest of the shortwaves will move through Monday
morning, bringing scattered showers to the entire area. Average
rainfall totals will be around a tenth of an inch on Monday with
the precipitation tapering off by early afternoon. Cool and dry
high pressure will build in Monday night into Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Dry high pressure will prevail through Thursday, then a
reinforcing cold front will sweep through Friday.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
The 12z TAF period begins with widespread IFR conditions which
are expected to persist through the entire forecast period.
Light rain is gradually increasing in coverage across the region
and will continue to do so through the morning. When rain moves
through, visibilities will lower but ceilings should remain the
controlling element for flight categories. Steady rainfall is
expected to take hold by late morning and then persist into the
evening hours. This will bring ceiling heights and visibilities
down for through the afternoon hours. Rainfall will come to an
end from north to south during the evening hours, but IFR
ceilings will remain. Though rain will likely end late in the
TAF period, IFR conditions will persist thanks to low ceilings
and the increasing potential for fog. For now, model guidance
suggests that dense fog should remain inland of the TAF`s.

Extended Aviation Outlook: A relatively prolonged period of
MVFR with occasional IFR ceilings expected through Monday.
Periods of rain showers could occasionally reduce visibilities
as well. Improving conditions later Monday or Monday night.

&&

.MARINE...
Today through tonight: A front will remain positioned south and
southeast of the local waters which will support modest
northwest flow through most of the period. Wind speeds aren`t
expected to be any higher than 10-15 knots, and will likely drop
off to 5-10 knots overnight while turning out of the north and
northeast. Seas should average 2-3 feet. Rounds of light
rainfall and drizzle, as well as very low clouds could produce
some visibility issues at times, but no true fog development is
expected.

A brief period of Small Craft Advisory winds is possible Monday
night as cold high pressure builds in.

&&

.TIDES/COASTAL FLOODING...
Upcoming high tide (~8:30 am): Low tide has passed at Charleston
and the tidal departure has remained around 0.3 ft. Based on
local forecast tool calculations, this should be sufficient to
give us a peak tide around 7.1-7.2 ft MLLW. Therefore, a Coastal
Flood Advisory has been issued for Charleston and coastal
Colleton counties.

Astronomical tides will remain elevated through Sunday but will
be on a declining trend. Coastal Flood Advisories could be
needed for the Sunday morning high tide cycle, but the current
forecast is for Charleston to fall just shy of the minor coastal
flood threshold.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until 11 AM EST this morning for SCZ049-
     050.
MARINE...None.

&&

$$

NEAR TERM...BSH
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...BSH/JRL
MARINE...BSH/JRL