441
FXUS62 KCHS 091451
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1051 AM EDT Sun Jun 9 2024

.SYNOPSIS...
High pressure will remain across the region today. A cold front
is expected to sweep across the forecast area on Monday. The
pattern is expected to turn more unsettled mid to late next
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Mid morning update: Full on sunny skies dominate at the moment
although there is some higher cloud cover that will be pressing
into the northern part of the forecast area as we go through the
day. That might have some impacts on temperatures. But
temperatures are already running around 5 degrees warmer than
this time Saturday. Middle to upper 90s forecast highs appear on
track...cooler near the coast of course.

Previous discussion...
At sunrise, visible satellite images showed a patch of stratus
and fog across portions of the SC Lowcountry. A few locations
observations across the SC Lowcountry observed visibility less
than an half a mile. Ongoing 12Z KCHS sounding indicated that
the llvl moisture associated with the stratus was around 5 mbs
thick. It is anticipated that the stratus and fog will dissipate
within the first two hours of daylight this morning. Thinning
debris cirrus may arrive from the northwest by mid-morning, with
waves of cirrus passing over the forecast area through the rest
of the afternoon. By this afternoon, few to scattered cumulus
with bases above 6 kft should develop by noon.

Weak high pressure should remain across the CWA today. A cold front
is timed to move from the Southern Appalachians this morning to over
the Fall Line by late this afternoon. As a result, sfc winds will
remain from the west through this afternoon. However, recent runs of
the HRRR indicates that a sea breeze should remain pinned along the
coast through mid-afternoon, then slowly drifting inland late this
afternoon. Forecast soundings this afternoon show an inversion
centered at H7, with weak instability capped by around 100 J/kg of
CIN.

Given the strong June insolation, west winds, late sea breeze, high
temperatures are forecast to range in the mid to upper 90s this
afternoon. In fact, the KCHS high temperature could challenge the
record high of 99 degrees set in 1986. Heat index values are
forecast to peak between 100-103 across the coastal counties.

Tonight, a cold front is forecast to reach the coast by 6Z, pushing
across most of the coastal waters by daybreak Monday morning. High
resolution guidance indicates that showers and thunderstorms will
develop across the western Carolinas, along and ahead of the cold
front, this afternoon. These thunderstorms should track southeast,
outpacing the cold front. Based on the latest HREF, indicates that
the convection will arrive after sunset with weakening updrafts. The
forecast will feature SCHC for showers and thunderstorms. The SPC
convective outlook for tonight shows a Marginal Risk across portions
of the SC Lowcountry. The late arrival of the convection and poor
environment, no severe weather is expected at this time. Low
temperatures should range from the low 70s inland to the mid to
upper 70s along the coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Monday, a H5 trough will amplify across the southern Appalachians
and Deep South during the daylight hours. A frontal wave is expected
to develop along the old cold front across southern GA Monday
afternoon. As the frontal wave develop, CAPE across extreme SE GA
may build to 1000-1500 J/kg along with weak shear. This environment
could support loosely organized clusters of thunderstorms across SE
GA. HREF indicates that SE GA will have a 10-30 percent chance for
updraft strength in excess of 30 m/s. One or two of these
thunderstorms may produce damaging wind gusts. In addition, PW
values may build to 1.7-1.8 inches in the vicinity of the frontal
wave, supporting heavy downpours. The forecast will indicate the
greatest coverage along the coast of GA and portions of the SC
coast. Storms should gradually push over the coastal waters Monday
evening. High temperatures may range from the upper 80s across
inland GA/SC to the mid 90s across SE GA. Showers and thunderstorms
should push east through the night as the mid-level trough ripples
over the region. Low temperatures should range in the upper 60s to
low 70s.

Tuesday and Wednesday, mid-level ridging should increase across the
forecast area. At the sfc, weak high pressure is forecast to remain
centered over the Mid West to Mid Atlantic. There appears to be
enough moisture across the region to support diurnal isolated to
scattered showers and thunderstorms each day. Temperatures should
remain slightly above normal.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The long term appears unsettled with low confidence with the details
of the forecast. Generally, long term guidance indicates that a
plume of deep moisture will linger across the Southeast U.S. during
the late week. Global models indicate that sfc low pressure may
develop over the Gulf of Mexico, however, guidance has tremendous
spread. Generally, the forecast will feature diurnal PoPs for
showers and thunderstorms each day. Temperatures should range around
normals.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Tonight: Prior to the 12Z TAFs, visible satellite images showed
a patch of stratus and fog across portions of the SC Lowcountry.
Recent observations from KCHS and KJZI indicated at least LIFR
conditions for ceilings and low visibilities. Ongoing 12Z KCHS
sounding indicated that the llvl moisture was around 5 mbs
thick. It is anticipated that the stratus and fog will dissipate
over KCHS and KJZI by 13Z. VFR conditions expected to continue
through the rest of the TAF period. A cold front is expected to
sweep across the KCHS and KJZI tonight, winds veering from NW by
9Z. The front is expected to stall near KSAV late tonight as a
frontal wave develops across SE GA.

Extended Aviation Outlook: The chance for convection and
periodic flight restrictions increases Monday through Thursday.

&&

.MARINE...
The sfc pattern will support southwest across the marine zones
today, speeds between 10-15 kts. Seas should remain between 1-2 ft
today.

Tonight, a cold front is forecast to reach the coast by 6Z, pushing
across most of the coastal waters by daybreak Monday morning. As the
front approaches, SW winds may surge with gusts around 20 kts. Winds
are time to veer from the northwest during the pre-dawn hours. Seas
are forecast to build to 2-4 ft during the wind surge ahead of the
cold front.

Extended Marine: A weak area of low pressure may track along the
front, across portions of the waters on Monday. Winds are forecast
to remain 10 kts or less with 1-2 ft seas. However, clusters of
thunderstorms may track across the waters Monday afternoon and
night. High pressure should build across the region Tuesday into
Wednesday. Unsettled weather may develop Thursday and could linger
into the late week. Conditions are expected to remain below Small
Craft Advisory criteria.

&&

.CLIMATE...
Record High Temperatures
June 9:
KCHS: 99/1986

&&

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

&&

$$

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