710
FXUS62 KCHS 050805
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
305 AM EST Wed Feb 5 2025

.SYNOPSIS...
A cold front will stall over the area today and tonight, then
lift north Thursday. Another front may approach the area Friday
night, then high pressure will build in through Sunday. A storm
system will bring unsettled weather to the area early to mid
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: 05/07z surface analysis placed a west-east oriented cold
front stretching across then northern portions of the Deep South
into North Carolina. The front will begin to backdoor into South
Carolina and central Georgia later today as 1040 hPa high
pressure centered over northern Minnesota bridges the central
Appalachians and noses south through the piedmont and coastal
plains of the Carolinas. How far south the front traverses today
is still in question with a number of possible solutions noted
in the 05/00z guidance suite. This will obviously have a large
impact on the temperature forecast for this afternoon.

The general consensus trend for areas this far to the south is
for an overall warmer solution with the lack of diabatic
processes occurring within the core of the wedge, thus delaying
the southward penetration of wedge front into southern South
Carolina until late in the afternoon. This uncertainty is noted
in the latest HREF Grand Ensemble showing as much as a 9-12
degree spread across the 25th/75th percentiles. The high
temperature forecast was adjusted to utilize a blend of the
warmer H3R, RAP and NBM hourly forecasts, making some slight
adjustments near the land/sea interface where an incredibly
tight thermal gradient will occur due to the influence of the
colder Atlantic. The yields highs in the lower-mid 70s over the
Charleston Tri-County and extending west for the counties
bordering to the CSRA/Southern Midlands to the upper 70s/near 80
elsewhere away from the beaches. The beaches will remain
considerably colder with highs only topping out in the upper
50s/lower 60s.

There is obviously a big bust potential with the high temperature
forecast, so adjustments, possibly significant, may need to be
made later today as near term trends on frontal placement become
more apparent.

Tonight: The wedge front will finally begin to ooze farther to
the south overnight as diabatic processes increase in response
to isolated to scattered showers falling across the core of the
wedge. The front is expected to become stationary somewhere
between I-16 and the Altamaha River. Southern stream shortwave
energy is forecast to traverse the region overnight with the
best, albeit weak, upper forcing is progged to remain to the
north across the Pee Dee and Midlands. Still, expect isolated to
perhaps scattered showers to impact the area overnight the
local coverage maxima occurring across the Charleston Tri-
County. Pops will range from 20-40%, highest across the
Charleston Tri- County with little, if any, meaningful QPF. Lows
tonight will range from upper 40s/lower 50s over Charleston,
Berkeley, Dorchester and Colleton Counties to the mid 50s
elsewhere.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
The surface front is expected to be stalled along the SC/GA
border at daybreak Thursday, though the vort energy should be
moving off the coast by then so rain chances are minimal. The
front will lift north as a warm front Thursday morning with
clearing skies and highs rising into the upper 70s to lower 80s.
The surface front may drift back south into the area on Friday
though it will be rather diffuse. While we cannot rule out a few
showers Friday and Friday night across southern SC, mainly dry
conditions expected with highs around 80 away from the coast.
Atlantic high pressure will rebuild on Saturday, pushing the
stalled front well north of the area. Highs across interior
southeast GA could climb into the lower 80s while areas along
the Santee River in SC top out in the lower 70s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
Atlantic high pressure will prevail through Sunday with another
unseasonably warm day in store with highs in the lower 80s. A
broad upper trough will take shape over the CONUS while Canadian
surface high pressure begins to wedge down the Eastern
Seaboard. Cold advection and extensive cloud cover will result
in temps a bit closer to normal. A series of upper disturbances
will move through, bringing periods of rain showers.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
05/06z TAF Discussion:
KCHS/KJZI: Some shallow ground fog could form at either terminal
through daybreak. A wedge front is forecast to drop into the
area later today, but its ultimate position is a bit unclear.
This will have implications on the ceiling forecast for the 06z
TAF cycle. Most of the near term guidance keeps the front just
north of the terminals until mid-afternoon with only VFR cigs
dominating. The forecast leans into these scenarios. After mid-
afternoon, the risk for MVFR or lower cigs increases. Cigs were
capped at 2000 ft for now to trend, but could end up lower.
Isolated to scattered showers will push through the terminals
late. No mention was included as any brief impacts would likely
occur at the end of the 06z TAF period.

KSAV: There is a risk for a stint of low clouds and fog at the
terminal before daybreak, but how low and to what extent the fog
will become is unclear. Condensation pressure deficits are
marginal for meaningful fog, but near term guidance suggests any
fog that develops could be locally dense. For now, cigs were
limited to 400 ft in a TEMPO group from 10-13z with prevailing
around 800 ft through mid-morning. Otherwise, VFR will prevail
by mid-morning, although VFR cigs will be in place. The risk for
MVFR cigs will increase by mid-evening with the passage of a
wedge front from the north.

Extended Aviation Outlook: Flight restrictions in fog and/or low
stratus is possible during the overnight and/or early morning
periods at the terminals.

&&

.MARINE...
Today: Light winds will prevail across the local marine area
today as wedge front tries to move south. The position of the
front through the day is somewhat uncertain and will have an
impact on wind speeds and directions. South of the front, winds
will remain southerly with northeast winds behind the front.
Speeds look to remain fairly light with speeds 5 kt or less,
except possibly 5-10 kt across portions of the South Santee-
Edisto Beach nearshore leg where some penetration of the wedge
front could occur. Seas will average 1-2 ft within 20 NM and
2-3 ft over the Georgia offshore waters out 20-60 NM.

Tonight: The wedge front is forecast to move south into the
waters overnight. North to northeast winds will prevail with
speeds 10 kt or less. Seas will average 1-2 ft, except 2-3 ft in
the South Santee-Edisto Beach nearshore leg and the Georgia
offshore waters out 20-60 NM.

Thursday through Sunday: South to southwest flow will generally
continue as Atlantic high pressure remains offshore. A few wind
surges are expected, though the forecast currently remains
below advisory thresholds.

Sea fog will remain possible during the period due to moist
southerly flow over cooler shelf waters.

&&

.CLIMATE...
Record High Temperatures:

February 5:
KSAV: 82/2008

February 6:
KCHS: 78/2019
KSAV: 82/2008

February 7:
KCHS: 80/2019
KSAV: 82/2019

February 8:
KSAV: 82/1921

February 9:
KCHS: 80/1949
KCXM: 76/1921
KSAV: 83/1957


Record High Minimum Temperatures:

February 7:
KSAV: 62/1884

February 8:
KCHS: 59/2017
KSAV: 62/1921

February 9:
KCHS: 60/1949
KCXM: 60/1949

&&

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

&&

$$