345
FXUS62 KCHS 101138
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
738 AM EDT Fri May 10 2024

.SYNOPSIS...
A cold front will push offshore today. 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 /THROUGH TONIGHT/...
The updated forecast will adjust PoPs and Wx to align with
recent radar trends. In addition, QPF across SE GA was increased
by an additional quarter of an inch.

Earlier this morning, a cluster of thunderstorms dissipated
upstream of the forecast area over southern GA. This activity
created a outflow boundary that surged south, nearing the FL/GA
line. Recent SPC mesoanalysis shows that nearly all of central
and southern GA has little to no SBCAPE and CIN has increased to
250-400 J/kg. In addition, in the wake of the dissipating
convection, the mid- levels have warmed and lapse rates have
decreased to around 6.5 C/km. HRRR forecast soundings indicate
that some elevated instability will remain across the region
this morning, with a gradient of around 500 J/kg over central GA
to 1500 over extreme southern GA. The gradient of elevated CAPE
is depicted well with the SPC mesoanalysis of NCAPE, with a
belt of 0.2-.025 from southern LA east to the FL/GA line. The
upstream MCS over the Deep South will remain in a corridor of
effective bulk shear of 45-60 kts this morning. Recent runs of
the HRRR suggests that the convection will track a bit south of
due east, tapping into the greater instability closer to the
Gulf Coast. Based on the HRRR, a bowing line of thunderstorms is
timed to reach the GA coast south of St. Catherines Island by
14Z. The organized line of thunderstorms will likely produce
strong to damaging wind gusts. This area has been highlighted
with Severe Thunderstorm Watch #230, in effect until noon. To
the north, the environment should support a broad band of
showers and thunderstorms across SE GA and the SC Lowcountry
this morning. The potential for severe thunderstorms will remain
limited north of the main squall line.

The forecast area should remain under a deck of anvil clouds this
morning, gradually decreasing this afternoon. Winds should remain
from the west-southwest through this afternoon ahead of an
approaching cold front. High temperatures are forecast to peak in
the low to mid 80s. As the cold front reaches the Fall Line around
sunset, a belt of 1000-1500 J/kg of CAPE should pool just ahead of
the cold front. High resolution guidance indicates that scattered
thunderstorms will develop along and ahead of the cold front,
tracking over the inland counties. However, the window for
convection will shorten after sunset and conditions become
increasingly stable.

The cold front is timed to push off the coast by midnight. In the
wake of the front, winds should shift from the north with steady
CAA. Given ongoing CAA through daybreak Saturday, low temperatures
are forecast to generally range from the mid 50s inland to around 60
along the coast.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Saturday and Sunday: Broad troughing will prevail aloft through the
weekend, with high pressure building in at the surface. With high
pressure dominating at the surface, the weekend will feature a
rather benign weather pattern. Temperatures on Saturday will
actually be much cooler than the previous week, owing to FROPA on
Friday night. Highs on Saturday are forecast to peak in the mid to
upper 70s. Sunday will be slightly warmer, with highs in the low
80s. Sunshine will be plentiful, accompanied by a rain-free
forecast.

Monday: The upper level pattern shifts a tad on Monday, with models
indicating a few shortwave troughs could ripple across the forecast
area. This could provide enough forcing for isolated to scattered
showers and thunderstorms. Temperatures are forecast to reach into
the upper 70s to low 80s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Beginning Monday night the forecast turns more active as a warm
front approaches the forecast area from the south. Aloft, a mid-
level trough is forecast to swing through the southeastern states
through Thursday. MOisture is expected to build into the region
after the warm front lifts northward, with PWATs approaching 2".
Several rounds of showers and thunderstorms are expected as the
region remains well within the warm sector with plentiful moisture,
aided from the approaching mid-level trough. Temperatures are
expected to gradually warm through the period, with upper 70s to low
80s on Tuesday warming to the mid to upper 80s by Thursday.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Prior to the 12Z TAFs, IR satellite indicated widespread debris
clouds across the terminals. The main challenge will be the
timing and intensity of MCS, located over southern AL and MS
before 12Z TAFs. Based on the majority of the CAMs, the core of
the MCS track along the FL/GA this morning. A band of showers
and thunderstorms on the north side of the MCS is timed to pass
over KSAV, expected between 13-17Z. The KSAV TAF will feature a
mention of SHRA with VCTS between 13-17Z, with a TEMPO for TSRA
from 14-17Z. KCHS and KJZI, the coverage TSRA will remain
limited, the TAFs will feature TEMPOs for TSRA between 14-16Z.
Late in the afternoon, a narrow band of showers and
thunderstorms will develop along a cold front west of the
terminals. After sunset, the coverage of showers and
thunderstorms will decrease as the front approaches the
terminals. The cold front is time to pass over the terminals
between 3-4Z, turning winds from the NW at 10kts.

Extended Aviation Outlook: VFR conditions will prevail through the
weekend. Showers and thunderstorms could bring flight restrictions
to the terminals Monday afternoon into the middle of next week.

&&

.MARINE...
A line of thunderstorm could push across the GA waters this
mornings. These storms may yield wind gusts in excess of 35 kts,
Special Marine Warnings may be issued. Otherwise, winds should
remain from west-southwest between 15-20 kts. Wave heights are
forecast to range between 3-4 ft. This evening, a cold front will
approach from the northwest, timed to reach the coast around
midnight. The front should rapidly sweep across the marine zones,
turning winds from the north. Speeds will favor values between 15 to
20 kts, gusts could reach 25 kts at times. Seas will change very
little overnight, remaining between 2-4 ft.

Saturday through Wednesday: Generally tranquil marine conditions are
forecast through the weekend as high pressure extends over the local
forecast area. Winds will generally be around 10 knots, with seas
averaging 1 to 2 feet. Monday night S to SE winds will surge
slightly as a warm front lifts northward through the region,
generally around 15 knots with some gusts around 20 knots. Seas will
also increase, averaging 3 to 4 feet. These conditions will persist
into the middle of the week.

&&

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

&&

$$

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