416
FXUS62 KCHS 070232
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
932 PM EST Thu Mar 6 2025

.SYNOPSIS...
High pressure will prevail into Saturday. A cold front is
expected to move through the area Saturday night into Sunday as
low pressure develops along it, and pulls away over the
Atlantic early next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The sky should remain clear through the rest of this evening.
Given the onset of weak H85 WAA and relaxing pressure gradient,
winds have settled to generally 5 mph or less across the
forecast area. Light winds and clear sky cover should result in
steadily cooling temperatures through late tonight. The forecast
update will feature adjustments to hourly winds, temperatures,
and dewpoints.

Tonight: The mid-levels will consist of a negatively tilted
trough moving further into the Atlantic. Meanwhile, weak ridging
over the MS Valley in the evening will shift eastward and
weaken. The result will be northwest winds overhead initially
will become more westerly late as zonal flow develops. Surface
high pressure near the mouth of the MS River in the evening
will shift over the Southeast U.S. late. The high will bring
dry conditions. Though, there should be some higher cloud cover
floating over our region. This along with very light to calm
surface winds will lead to decent radiational cooling.
Temperatures are expected to bottom out in the lower to middle
30s across most areas, except warmer at and near the beaches.
All of this will cause areas of frost to form across inland
areas. Therefore, we have a Frost Advisory in effect. Closer to
the coast, the frost should be more patchy, so we don`t have an
advisory there at this time.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Friday: The day begins cool with frost many places inland from
US-17. But with zonal flow to prevail aloft, it will allow for
surface high pressure initially directly overhead to move
offshore for the afternoon. With the strengthening March sun,
and warm advection, highs will be 5-10F warmer than on Thursday.
The immediate coast will be considerably cooler with a
resultant afternoon sea breeze.

Friday night: It`ll also be a warmer night with a 35-45 kt low
level jet passing through, keeping things well mixed within the
boundary layer. This occurs in response to an upstream cold
front and high pressure to the south and southeast. Lows only
look to be within a few degrees either side of 50F.

Saturday: A deep downslope flow will dominate the region ahead
of a cold front not far to the north of the area. This along
with warm advection will promote a very warm day for this time
of year, and provided there is enough sunshine available ahead
of a developing system in Texas, highs will reach into the mid
and upper 70s, with gusty westerly breezes The sea breeze will
be pinned close to the coast within this pattern, But keep in
mind if you`re going to the beaches, they will be much cooler in
the afternoon due to the eventual development of that sea
breeze. Most if not all of the day will be rainfree, with just a
slight chance late southern areas as a weak short approaches.

Saturday night and Sunday: The next system to impact the local
vicinity will be in response to a backdoor cold front that
passes into the area late Saturday night, and clears most, if
not all locations Sunday. Low pressure rides eastward along the
front from the Deep South, and within a moister flow out of the
Gulf, and isentropic ascent, we look for showers to spread into
the area. Guidance is still somewhat mixed regarding how quickly
his occurs, but given forcing for ascent with short waves
aloft, the right entrance region of the jet nearby, and some
indications of 850-700 frontogenesis, it promises to be a wet
period. PoPs as of this time are 60-80%, but 90-100% PoPs will
likely be required at some point. The risk for any thunder is
limited due to minimal CAPE. But since thunder was already
mentioned in the forecast, there is some elevated instability,
and the NBM has low chances, we do show slight chance t-storms
during Sunday. Most lows Saturday night won`t drop out of the
50s, and highs Sunday will be much cooler than on Saturday.
Depending upon the exact track of the surface low and how far
south the cold front pushes, adjustments could be forthcoming.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A strong short wave drops through the area early in the week,
causing the surface low to deepen off the Southeast coast. This
low then pulls away either late Monday or Monday night, before
high pressure builds in again through Wednesday. Another short
wave and possible surface low could approach from the west
Thursday. It still looks wet Sunday night into Monday, with
eventually drier weather to return late in the period. Cool
conditions Monday, then much warmer thereafter.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
0Z TAFs: VFR. A sea breeze may push across the terminals late
Friday afternoon, followed by southwest winds around 10 kts.

Extended Aviation Outlook: There could be LLWS Friday night
into early Saturday as a 35-45 kt low level jet moves through. A
storm system could bring flight restrictions to the area late
Saturday night or Sunday into Monday or Monday night.

&&

.MARINE...
Tonight: High pressure near the mouth of the MS River in the
evening will shift over the Southeast U.S. late. Cold air
advection will quickly wane around sunset and the pressure
gradient will level off. This will cause winds to rapidly ease.
Hence, the Small Craft Advisories should expire by midnight.

Friday and Friday night: High pressure is in control, and the
gradient is light enough during Friday for afternoon sea breeze
circulations. Winds though remain no more than 10 or 15 kt.
However, the gradient does start to tighten Friday night as an
upstream cold front begins to draw closer, and a 35-45 kt low
level jet moves in. Warm advection will temper the amount of
mixing of these winds at night, but there could be some gusts of
20 or 25 kt at times.

Saturday through Tuesday: High pressure eventually gives way to
a cold front late Saturday night and early Sunday, as low
pressure rides along the front, and deepens not far away from
the local waters into Monday or Monday night. As that feature
pulls away thereafter, high pressure builds in from the west.
Conditions could be close to advisory levels with a pinched
gradient Sunday through Monday.

Mariners are advised that a few t-storms are possible Sunday
into Sunday night given some elevated instability. Nothing
severe however.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Frost Advisory from 1 AM to 8 AM EST Friday for GAZ087-088-
     099>101-114-115.
SC...Frost Advisory from 1 AM to 8 AM EST Friday for SCZ040-042>045.
MARINE...Small Craft Advisory until midnight EST tonight for AMZ374.

&&

$$

NEAR TERM...NED
SHORT TERM...
LONG TERM...
AVIATION...NED
MARINE...