246
FXUS62 KCHS 101923
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
323 PM EDT Fri May 10 2024

.SYNOPSIS...
A cold front will push through the area tonight. High pressure
will prevail for the weekend into early next week. A storm
system could affect the area by the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
This evening and tonight: Satellite imagery shows cirrus
steadily thinning and shifting to the east while a cumulus field
is quickly filling in. Surface analysis shows that the cold
front stretches from central Georgia through the South Carolina
Midlands. This front will track to the southeast through the
evening and shift offshore by the early morning hours. Along the
front, we are seeing instability start to pool and this should
be enough to trigger isolated to scattered convection this
afternoon and into the evening. In fact, the first storms have
already developed near the NC/SC state line. For our forecast
area, the question is how much recover will there be over the
next few hours and will these upstream storms along the front be
able to move into portions of the area. Model guidance suggests
that MLCAPE as high as 1,000-1,500 J/kg will be possible right
along the front by early evening. The main area of concern for
convection, and a couple of strong to marginally severe storms,
will be for interior southeast South Carolina and especially
inland Colleton, Dorchester, and Berkeley counties. This aligns
with where the SPC Day 1 Marginal Risk is in place, and we will
continue to highlight the threat in the Hazardous Weather
Outlook. Flow in the mid-levels will be strong enough to yield
0-6km shear around 50 knots and 0-3km shear around 30 knots. So
any storms that develop will have a damaging wind gust
potential, as well as large hail potential. All convection
should shift offshore by the mid to late evening hours, and the
rest of the overnight will be dry. The front will shift offshore
and northerly flow will usher in much cooler and drier air.
Overnight lows are forecast to range from the mid 50s inland to
the upper 50s and low 60s along the coast.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday and Sunday: A stout northwest flow will dominate aloft
as surface high pressure builds in from the west. Quiet, dry
conditions will prevail with forecast soundings showing modest
capping aloft with low net moisture values (PWATs <1"). A modest
west/northwest flow atop the boundary layer should delay/pin
the afternoon resultant sea breeze both afternoons. Low-level
thickness values support highs in the upper 70s/near 80 on
Saturday warming into the lower 80s on Sunday. Lows Saturday
night will drop into the mid- upper 50s inland with mid 60s at
the beaches with upper 50s/lower 60s inland and upper 60s/near
70 at the beaches Sunday night.

Monday: A warm front will begin to organize to the south and
move north into the area as a storm system develops to the west.
Isolated to scattered showers/tstms could develop near this
feature in the afternoon, but the bulk of anything meaningful
looks to remain south of the Altamaha River. Forecast soundings
north of the warm front are not overly unstable with meager
MLCAPE, positive LI`s with K- indices <30C noted, so conditions
do not look overly favorable for deep convection despite highs
warming into the upper 70s/lower 80s. Pops 20-30% look
reasonable during this time with any mention of thunder being
confined to mainly Southeast Georgia due to some uncertainty on
location/timing of the developing warm front.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Monday Night and Tuesday: Rain chances will increase Monday
night into Tuesday as a warm front lifts north and the region
becomes fully embedded within the warm sector of an approaching
storm system. Modest forcing for ascent ahead of a number of
southern stream impulses embedded ahead of a shortwave that digs
across the Tennessee and Ohio Valleys will steadily increase
within an increasingly moist environment. There are a few model
signals that a large convective complex along the northeast Gulf
coast/Florida Panhandle could disrupt moisture transport into
the area which could limit the amount of convection over
Southeast South Carolina and Southeast Georgia Tuesday. These
trends will have to be watched carefully. For now, a blend of
the NBM with the drier SuperBlend consensus was used to
construct pops. Pops 60-70% were highlighted for Monday night
with 80% pops for Tuesday. Lows Monday night will range from the
lower 60s well inland to the lower 70s at the beaches. Highs
Tuesday will warm into the upper 70s/lower 80s, limited by
extensive cloud cover and showers/tstms.

Wednesday and Thursday: Overall, rain chances will be lower for
Wednesday into Thursday, but some degree of convection can be
expected as a series of weak fronts/troughs move through the
Southeast States. Chance pops were highlighted during this time.
Temperatures will be near to slightly above normal for both
days.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions should prevail at KCHS, KJZI, and KSAV through
18z Saturday. The main forecast challenge will be the potential
for isolated to scattered showers and thunderstorms late this
afternoon and early this evening, primarily near KCHS and KJZI.
We have added in a few hours of VCSH as the confidence of direct
impacts at KCHS and KJZI remains low. A thunderstorm will be
possible too, but chances aren`t high enough to include a
mention of TSRA. Whatever activity does develop will shift
offshore in the evening and the rest of the period will be dry.
Skies will clear out overnight as well. Winds will turn
northwesterly and then northerly overnight.

Extended Aviation Outlook: Showers and thunderstorms could
bring flight restrictions to the terminals Monday afternoon into
the middle of next week.

&&

.MARINE...
Tonight: Elevated west-southwest flow will continue this
evening, with a solid 15-20 knots and a few isolated gusts up to
around 25 knots. An inland cold front will shift offshore by
the early morning hours and winds will turn northwesterly and
eventually northerly. Wind speeds will remain elevated into the
15-20 knot range. A few gusts up to around 25 knots will be
possible, but we have opted to not issue any Small Craft
Advisories at this time as winds should remain below criteria
most of the time. Seas are forecast to average 2-4 feet through
the night.

Saturday through Wednesday: There are no concerns through
Monday. The risk for Small Craft Advisory conditions will
increase Monday night into Tuesday as a warm front lifts north
and storm system approaches from the west.

&&

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

&&

$$

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