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242
FXUS62 KCHS 192027
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
427 PM EDT Sun May 19 2024

.SYNOPSIS...
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High pressure will build in from the north tonight and persist
through most of this week. A series of upper level disturbances
will impact the area next weekend.
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&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Satellite water vapor indicated the center of a mid-level vorticity
maximum over southeast GA, tracking to the SE. A band of strong to
severe thunderstorms developed along a cold front earlier this
afternoon. This band will continue to slide south developing ahead
of the cold front and just north of an outflow boundary, tapping
into a unstable environment. CAPE in excess of 2000 J/kg, DCAPE
between 600-800 J/kg, and effective bulk shear around 30 kts may
continue to support strong to severe thunderstorms across extreme SE
GA through the rest of the afternoon. These storms may produce
damaging wind gusts and even hail up to the size of Quarters. These
storms are timed to slide off the GA coast by early this evening.

PW values will remain around 1.6 inches through the rest of this
afternoon. The combination of deep instability, adequate atmospheric
moisture, and storm motions less than 25 MPH could result in pockets
of torrential downpours. The greatest rainfall rates should occur
with the passage of strong to severe thunderstorms across SE GA.
However, another cluster of showers and thunderstorms has persisted
over Charleston County this afternoon, with little to no motion.
This area of rainfall should gradually dissipate through the rest of
this afternoon.

This evening, convection should spread east across the adjacent
waters, followed by an area of stratiform rain. The latest runs of
the HRRR indicates that the rainfall will become limited to isolated
to scattered showers and thunderstorms by mid-evening. Conditions
should continue to dry through the rest of the night. Rain cooled
air should keep temperatures in the 60s and 70s this evening, then
cooling into the low to mid 60s late tonight.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
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Deep layered ridging will occur Monday through Wednesday,
bringing dry weather and warming temperatures. There will be
weak cold advection on Monday as the surface high remains to the
north. This will keep highs in the lower 80s, except upper 70s
near the coast where a decent sea breeze will develop. The
surface high will shift off the coast Monday night as the upper
ridge continues to build. Increasing thicknesses Tuesday into
Wednesday will produce a warming trend with highs in the mid 80s
Tuesday and upper 80s Wednesday.
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&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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Deep layered ridging will continue Wednesday night through
Friday, with above normal temperatures continuing. A series of
shortwaves will then impact the area late Friday afternoon
through early next week, bringing scattered showers and
thunderstorms.
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&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
KSAV: A cluster of strong to severe thunderstorms will reach
the KSAV terminal by 19Z. The KSAV TAF will feature moderate
thunderstorm at 19Z with a TEMPO from 19-23Z for gusts to 35 kts
and IFR vis. The thunderstorms are forecast to push south and
east of the terminal by early this evening. The challenge
overnight will be the formation of MVFR ceilings, expected to
develop by 3Z at KSAV. The stratus should mix out shortly after
daybreak on Monday with steady NE winds.

KCHS and KJZI: Prior to the 18Z TAFs, a cluster of showers and
thunderstorms was located over KLCO, drifting SW. This activity
will remain close enough to mention VCSH at both terminals
through 21Z. AMDs may become necessary later this afternoon if
the activity tracks over either one of the terminals. By late
this afternoon, convection should drift south of the terminals.
Steady NE winds with ceilings between 040-060 may remain through
the night.

Extended Aviation Outlook: VFR.

&&

.MARINE...
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Through the rest of the afternoon into early this evening, strong to
severe thunderstorms will track across the GA waters. A ridge of
high pressure should support strengthening NE winds across the
waters tonight. Speeds should range between 10-15 kts with gusts to
20 kts. Seas are forecast to gradually build to 3-4 ft.

Monday and Monday night, a decent NE gradient is expected as
high pressure remains to the north. A few 25 kt wind gusts are
possible in the coastal waters, and seas could briefly reach 6
ft over outer GA waters. The gradient will relax by Tuesday as
the surface high moves east and winds turn to the SE. A more
typical summer wind pattern will set up for mid to late week
with daily sea breezes along the coast.
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&&

.TIDES/COASTAL FLOODING...
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The combination of rising astronomical tides with the upcoming Full
Moon and moderate NE winds will cause tides to be elevated early
this week. Minor flooding is possible with the evening high tides
Monday through Wednesday along the South Carolina coast.
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&&

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

&&

$$

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