497
FXUS62 KCHS 231716
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1216 PM EST Sun Feb 23 2025

.SYNOPSIS...
High pressure will prevail today. A weak disturbance will pass
to our south tonight into Monday, followed by High pressure
through Wednesday. A cold front should move through on
Thursday, followed by more High pressure for next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early this afternoon: No change to the forecast. Previous
discussion continues below.

Late this morning: Aloft, zonal flow this morning will gradually
turn more southwesterly into the afternoon as a southern stream
shortwave starts to move out of the Southern Plains and into the
Lower Mississippi Valley. At the surface, weak high pressure
will persist across the region as an area of low pressure tracks
eastward near the central Gulf Coast. With precipitable water
values well below half an inch, the forecast is dry through the
day. We will see cloud cover, mostly cirrus, increase through
the day. Thanks to the weak pressure gradient, winds will be
light today in the 5-10 mph range. Northwest winds this morning
will back to become more westerly and then southwesterly by the
afternoon. Low-level thickness values continue to rebound and we
should see highs warm by 5-6 degrees relative to Saturday. Look
for temperatures to peak in the low 60s across southeast SC and
the low to mid 60s for southeast GA.

Tonight: The upstream short wave moves across the Deep South
and approaches the Southeast late, allowing for the surface low
to track east across the northern Gulf. Moisture does increase
somewhat in advance of these features, but guidance provides
differing solutions on how far north any rains will occur. It
will take time for the vertical column to moisten, given only
weak isentropic ascent, and PWat that is still barely 1 inch
across southern sections. Since there is forcing from the short
wave, and some divergence aloft with the upper jet, we do
foresee at least some risk for showers overnight. This is mainly
over Georgia, where the deeper moisture coincides with some
higher Theta-E air, and upward vertical velocities. For now we
show slight chance/chance PoPs after midnight over our Georgia
counties. Increasing and thickening clouds will prevent
temperatures from getting anywhere near as cold as recent
morning. Lows will range from the upper 30s far north and
northwest to the lower and middle 40s most elsewhere.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Monday: The mid-levels will consist of a shortwave stretching
from the Southeast U.S. towards southern TX in the morning.
It`ll slowly move eastward as time progresses, with it`s axis
stretching from the Carolinas down into FL late at night. At the
surface, a storm system will be impacting parts of the
Southeast U.S. in the morning. Most of the energy will remain
over FL during the day and into the evening. However, as the
system shifts off the east coast of FL overnight, it shows signs
of strengthening and trying to build back towards our area.
There remain some differences in the synoptic models regarding
the evolution of this storm system. But they all have the
heaviest rainfall remaining just to our south. The general
consensus is isolated to scattered showers across the southern
half of our forecast area during the morning and into the
afternoon. Showers should become limited to our coastal counties
from roughly Beaufort on south during the evening hours, then
try to backbuild towards Charleston County overnight. Measurable
QPF should remain mostly south of I-16, with up to 0.15" near
McIntosh County. Further north is more likely to remain dry
throughout the day and into the night. High pressure building in
from the west will bring dry conditions inland overnight. Highs
will be dependent on shower coverage, ranging from the lower to
middle 60s across our northernmost counties to the upper 50s
across our southernmost counties. Overnight, with partly cloudy
skies and calm winds inland, lows will be in the upper 30s. But
increased clouds near the coast should limit lows to the middle
to upper 40s, especially along the beaches.

Tuesday: A shortwave will stretch from the Carolinas down into
FL in the morning. It`ll move offshore by the afternoon, and
continue to move away into the overnight. This will yield west
northwest flow overhead. A storm system will be located to our
southeast in the morning, shifting away as time progresses. High
pressure will then build over the Southeast U.S. by the
overnight hours. The High will bring dry conditions. Partly
cloudy skies and northwest surface winds in the morning will
become mostly sunny skies and westerly winds by the afternoon.
This should lead to high temperatures above normal, mainly in
the lower 70s, except cooler at the beaches. Clear skies and
calm winds will cause plenty of radiational cooling. Lows will
range from the lower 40s far inland, to the mid 40s closer to
the coast, and warmest at the beaches.

Wednesday: The mid-levels will consist of mainly zonal flow
over our region. At the surface, High pressure over the
Southeast U.S. in the morning will shift offshore as the day
progresses. Expect dry conditions with mostly sunny skies. High
temperatures will again rise above normal, mainly in the middle
70s for most places, except cooler closer to the coast, and
coolest at the beaches due to onshore winds in the afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
High pressure will shift off the Southeast U.S. Wednesday
night. A cold front should bring a round of showers late
Thursday into Thursday night. High pressure and dry conditions
return on Friday and prevail into Saturday. High temperatures
should be above normal Thursday, then falling to near normal on
Friday, followed by warming a few degrees to above normal on
Saturday.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 18z Monday. An area of light showers is expected to
expand northward late tonight and Monday morning and could
impact the terminals. However, rainfall isn`t expected to be
intense enough to reduce visibilities and ceilings should mostly
be in the 6-8 kft range. The best chance of rain is at KSAV
where we carry prevailing showers starting at 10z. For KCHS and
KJZI, the showers could remain just to the south so we only
mention VCSH for now. There is a low chance for MVFR ceilings
around KSAV near the end of the TAF period.

Extended Aviation Outlook: VFR is then expected Monday through
Wednesday night. A cold front should bring flight restrictions
on Thursday.

&&

.MARINE...
Today: The local waters will lie on the eastern periphery of
continental high pressure, resulting in a relaxed pressure
gradient, and winds no higher than about 10 kt. Land breeze
influences early on will cause NW winds to prevail, before sea
breeze circulations develop in the afternoon, causing winds to
shift to a S and SW component. Since the bulk of the wave energy
is due to swells, our forecast has just 1 or 2 foot seas
throughout.

Tonight: Low pressure will shift across the northern Gulf, with
high pressure covering much of the eastern part of the country.
The pressure pattern remains very relaxed, and as a result S
and Sw winds that are just 10 kt or less, turn to the W and NW
overnight with land breeze influences. Seas yet again are held
to just 1 or 2 feet.

Monday: A storm system will be impacting portions of the
Southeast U.S. in the morning and afternoon. It`ll shift off the
east coast of FL in the evening and overnight. Though, it shows
signs of strengthening and trying to build back towards our
area. High pressure will also build in from the west in the
evening and overnight. Even with these synoptic features, winds
and seas are expected to remain low enough that no Small Craft
Advisories are expected.

Tuesday and Wednesday: High pressure will prevail, bringing
tranquil conditions.

Thursday: A cold front should move through late, bringing winds
and seas just short of Small Craft Advisory criteria.

&&

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

&&

$$

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