Summerville, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

704
FXUS62 KCHS 241141
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
641 AM EST Sat Jan 24 2026

.WHAT HAS CHANGED...
The aviation section has been updated to reflect the 12Z TAFs.

&&

.KEY MESSAGES...
- 1) Widespread precipitation is expected Saturday night
  through Sunday night, with freezing rain possible Saturday
  night into Sunday morning across inland portions of the SC
  Lowcountry and SE GA.

- 2) Very cold temperatures will occur Monday night into next
  weekend, with Cold Weather Advisories possible.

&&

.DISCUSSION...
KEY MESSAGE 1: Widespread precipitation is expected Saturday
night through Sunday night, with freezing rain possible Saturday
night into Sunday morning across inland portions of the SC Lowcountry
and SE GA.

A period of winter weather will begin tonight into Sunday morning
for portions of the forecast area. Aloft, extensive upper troughing
over the CONUS will persist into Sunday while an upper level jet
located over the Mid-Atlantic will spurn surface cyclogenesis in the
favorable right entrance region, off of the southeastern coast. With
this surface low forming offshore, the region will observe
widespread precipitation beginning Saturday night and lasting into
Sunday. As the low initially forms there are indications that
drizzle could develop Saturday evening across SE SC. Additionally,
at the surface high pressure centered over New England will create a
Cold Air Damming (CAD) regime east of the Appalachian Mountains. The
precipitation from the developing low pressure and the cold air from
the CAD will set the stage for wintry precipitation, mainly across
inland locations of SE SC and SE GA.

Freezing rain probabilities have not changed substantially over the
last 24 hours, with the greatest probabilities across inland
locations, where there is currently a Winter Weather Advisory in
effect from 7 PM Saturday night through 1 PM Sunday. Ice
accumulations up to a tenth of an inch are possible, especially on
elevated surfaces. There are a few forecast challenges with this
freezing rain, one of them being the strength of the CAD. Some high
resolution guidance, most notably the NAM12, show sub-freezing
temperatures surging further south and closer to the coast.
Additionally, the NAM has wet bulb temperatures in the upper 20s
across the advisory area and slightly further southward and into the
Charleston Metro Area. Diabatic cooling would occur with these wet
bulb temperatures, allowing temperatures to drop a few degrees
cooler. Both the NAM and the HREF show surface winds out of the
north across a large swath of the region, roughly north of I-16 in
SE GA and to the coastline in SE SC. This north wind will allow a
steady stream of cooler, drier air feeding into the region and
increasing the likelihood of freezing rain.

It is worth noting that some models, the HRRR and NAM3km for
example, have started to trend drier from previous runs. However,
with forecast low ceilings as well as probabilities for reduced
visibilities, the threat of drizzle is still evident. This
drizzle would be freezing drizzle across areas below freezing.

A strong cold front will then approach the region Sunday
afternoon/evening, putting the entire forecast area within the
warm sector. Hi-Res models are consistent in showing a line of
showers pushing through the region, producing generally 0.5" of
rain across the region. There could be enough instability to
support isolated thunderstorms Sunday evening, mainly along the
Altamaha in SE GA. Cold air will follow the cold front, however
all moisture is expected to be offshore by the time the cold air
arrives.


KEY MESSAGE 2: Very cold temperatures will occur Monday night into next
weekend, with Cold Weather Advisories possible.

Arctic high pressure will spread over the area behind a cold
front Monday, residing over the area through Wednesday. A
reinforcing cold front Thursday will be followed by another
Arctic high moving in from the northwest.

Monday night low temperatures are forecast to be the coldest for
the week, with lows in the upper teens far inland to lower 20s
elsewhere. 5-10 kt sustained winds through the night will
produce several hours of 10-15 degree wind chills. A Cold
Weather Advisory is likely for Monday night.

With decent boundary layer flow continuing during most overnight
periods this week and unseasonably cold temps, we could have a
few hours of 15-20 degree wind chills each morning into the
weekend. Additional Cold Weather Advisories are possible.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
VFR will initialize the 12Z TAF period at KCHS/KJZI/KSAV this
morning, however cigs are close to MVFR categories across the
region. These cigs should work into the terminals by mid
morning, along with NE winds gusting 20 to 25 knots. MVFR cigs
will linger all day as a wedge sets up across the region. As low
pressure develops off the southeastern coast rain and drizzle
will move across the SC terminals. Current forecast is that any
frozen precipitation will remain inland of the terminals,
however there is a low probability that KCHS/KJZI could see
freezing drizzle. The 12Z TAFs show MVFR cigs and vsbys through
the period, but IFR cigs and vsbys are possible, but confidence
was too low that late in the period to include mention at this
time.

Extended Aviation Forecast: Periods of MVFR and/or IFR
conditions are likely at all terminals this weekend as a storm
system develops in the Deep South and moves northward towards
the region on Saturday, yielding low cigs/vsbys into Sunday.
Expect a cold front to move across the region Sunday night and
yield VFR conditions through early next week.

&&

.MARINE...
A tight northeast gradient will exist today and tonight as
Arctic high pressure expands over the eastern United States.
Small Craft Advisories (SCAs) in effect for all waters. We`ll
need to monitor for possible Gale force gusts later this
afternoon over the nearshore waters, as some guidance hints at
winds getting particularly strong during this time.

A potent southerly flow will develop later Sunday ahead of a
cold front. SCAs exist for all waters except Charleston Harbor,
though we may eventually need to expand into the harbor for
gusts.

The advisories continue through Tuesday morning due to residual
6+ ft swells.

&&

.EQUIPMENT...
The KCLX radar will remain out of service. Critical parts are
on order and repairs are scheduled to occur this morning once
the parts arrive. Users should use adjacent WSR-88D sites,
including KCAE, KLTX, KJAX, KVAX and KJGX.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Sunday for GAZ087-088.
SC...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Sunday for SCZ040-042>045.
MARINE...Small Craft Advisory until 7 PM EST this evening for AMZ330.
     Small Craft Advisory until 10 AM EST Tuesday for AMZ350-352-
     354.
     Small Craft Advisory until 1 PM EST Tuesday for AMZ374.

&&

$$

CPM/JRL