708
FXUS62 KCHS 121445
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1045 AM EDT Wed Mar 12 2025

.SYNOPSIS...
High pressure is expected to prevail through the end of the
week. A cold front is expected to push through the region late
in the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Late morning temperatures are 6-10F warmer than the same time
yesterday. Based on this, and a greater thickness, we have
raised some temperatures 1-2F higher. The ECS MOS has been
performing well on sunny days the past couple of weeks, and we
opted to go more in that direction, since it is the warmer of
guidance. The sea breeze will be noticeably, especially along
the Charleston and Colleton coasts, as it holds those
temperatures down in the lower and middle 60s. Based off the
condensation pressure deficits of the HRRR, the sea breeze
forms around 12-1 PM, reaching near US-17 by 5-6 PM.

Today: Aloft, a mainly zonal flow takes place across the region with
subtle signs of mid-lvl ridging across the local area during the
afternoon. At the sfc, high pressure will remain stretched across
Florida into the western Atlantic, while weak troughing/stationary
front remain across the Mid-Atlantic states. The setup will favor
dry and sunny conditions across the area, with temps a few degrees
warmer than the previous day. 1000-850 mb thickness levels support
highs in the upper 70s to around 80 degrees for most areas. The
exception will be closer to the coast, where an afternoon sea breeze
takes shape and shifts inland, resulting in high temps in the upper
60s/lower 70s along the beaches.

Tonight: Dry conditions will prevail across the area under weak
ridging occurring from the west-southwest. At the sfc, high pressure
will become more centered across the western Atlantic well offshore,
while weak low pressure and nearly stationary front remain across
the Mid-Atlantic states. Winds are likely to decouple early evening
and the pressure gradient will remain weak, favoring light south-
southwest winds going calm away from coastal areas during the
evening. Strong radiational cooling is expected for the bulk of the
night with clear skies in place, although a few high clouds should
approach inland areas within a few hours of daybreak. In general,
low temps should dip into the mid-upper 40s inland to low/mid 50s
near the coast.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
A weak cold front will approach the region on Thursday as an upper
level shortwave trough ripples across the southeastern states.
Isolated showers could approach the far interior zones of the
forecast area late Thursday, however moisture will be rather limited
with PWATs <0.75". Temperatures on Thursday will reach into the mid
70s away from the direct coastline. High pressure will briefly build
into the region on Friday while slight ridging develops aloft over
the southeastern states. Quiet weather is expected both Friday and
Saturday, with highs reaching into the upper 70s to low 80s partly
sunny skies.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
A more active pattern takes shape Saturday night as a potent
positively tilted trough swings across the central CONUS and the
Deep South. At the surface a cold front will approach the region
Sunday. Widespread showers will be possible along with thunderstorms,
some of which may be severe. While forecast soundings depict
plentiful shear aloft, there is little to no instability across
the region. Instability remains the limiting factor in the severe
potential and will be monitored closely with further forecasts.
Temperatures will take a quick dive on Monday post-FROPA to
around normal, returning to above normal through the remainder
of the period as high pressure builds into the region again.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 12Z
Thursday.

Extended Aviation Outlook: Prevailing VFR through the end of the
week. Flight restrictions are possible with showers and thunderstorms
Saturday night into Sunday associated with a passing cold front.

&&

.MARINE...
Other than raising the winds in Charleston Harbor to 15 kt this
afternoon per sounding data, no changes required for the morning
update.

Today and Tonight: Quiet marine conditions will prevail between sfc
high pressure stretched across Florida into the western Atlantic and
low pressure/a stationary front across the Mid-Atlantic states.
Southwest winds ranging between 5-10 kt this morning should gradually
turn more southerly with time, topping out between 10-15 kt this
afternoon as sea breeze circulation develops and shifts inland.
Winds should then slowly tip back to southwest and remain around
10 kt or less overnight as sfc high pressure becomes more centered
across the western Atlantic well offshore. Seas will generally
range between 1-3 ft, but could reach 4 ft across outer Georgia
waters tonight.

Thursday through Monday: High pressure will dominate over the marine
waters through the end of the week and into the first part of the
weekend. Through Friday winds will average around 10 knots with seas
generally 2 to 3 ft. Dangerous marine conditions will develop this
weekend ahead of a cold front pushing through the region. Southerly
winds on Saturday and Saturday night will surge to 15 to 20 knots
with gusts to 25 knots and seas building to 5 to 6 ft in the
nearshore waters and 7 to 8 ft in the 20 to 60 nm offshore GA
waters. Some Gale force gusts cannot be ruled out. Small Craft
Advisories will likely be needed starting around Saturday afternoon
for all waters, including the Charleston Harbor. Winds and seas will
remain elevated through Monday.

&&

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

&&

$$

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