811
FXUS62 KCHS 220101
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
901 PM EDT Sat Sep 21 2024

.SYNOPSIS...
High pressure will linger across the region through early next
week. A weak cold front may approach from the west around the
middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
The boundary layer has decoupled inland which should spread to
the coast over the next few hours. Clear skies coupled with
calm/light winds will promote solid radiational cooling
conditions. Temperatures were already down into the upper
60s/near 70 across much of the Francis Marion National Forest
per 22/0030z observations. Lows from the mid-upper 60s inland
to the lower 70s at the coast and Downtown Charleston look on
track. A few lower 60s will be possible in some of the normally
cold spots such as the Francis Marion.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday: The center of a 590 DM ridge will remain centered over
TX as a closed low pivots off the coast of New England. Short
term guidance indicates that weak mid-level vort max is timed to
track across the forecast area during the afternoon.
Temperatures under the mid-level ridge will steadily warm
through the mid-afternoon, expected to peak in the low 90s for
most location. HREF indicates that sea breeze will develop
during the mid to late afternoon, surging inland. The hot
temperatures over dewpoints around 70 should result in CAPE
values between 500-1000 J/kg along and ahead of the sea breeze.
CAMs indicate that isolated showers may develop near the sea
breeze, primarily over the SC Lowcountry.

Monday and Tuesday The axis of a H5 ridge will ripple across
the forecast area. GFS forecast soundings indicate that a strong
inversion is expected to remain centered around H55, likely
keeping conditions capped. The forecast will feature dry and hot
weather for Monday and Tuesday. High temperatures are forecast
to range from the upper 80s to low 90s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Wednesday: The forecast area will remain under the influence of
the H5 ridge centered over the western Atlantic. At the sfc,
high pressure centered over the Mid-Atlantic States is expected
to ridge south across the region. It is possible that a sea
breeze could trigger isolated showers during the afternoon.
However, the degree of instability remain too uncertain to added
PoPs to the forecast. High temperatures should remain in the
upper 80s to around 90.

Thursday through Saturday: The details of the forecast will
largely depend on the intensity, placement, and timing of a
potential tropical system sourced from the Gulf of Mexico. See
latest NHC Tropical Weather Outlook for latest information.
Based on the collaborated low position, the system is expected
to remain to the west. The forecast will indicate generally
scattered showers at this time. Given the thick cloud cover and
anticipated rainfall, high temperatures are forecast to range
between 80-85 degrees.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
22/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR.

Extended Aviation Outlook: There are no concerns.

&&

.MARINE...
Tonight: Easterly winds 5-10 kt will prevail overnight with
seas ranging 2-3 ft within 20 NM and 3-4 ft over the Georgia
waters 20-60 Nm.

Sunday through Wednesday: The marine zones will remain under high
pressure through the period. Winds should generally remain from the
southeast between 5 to 10 kts with seas of 2 to 4 ft.

&&

.TIDES/COASTAL FLOODING...
Positive tidal anomalies and high astronomical tides from the
recent full moon will lead to elevated tides through early next
week. Although the astronomical high tides are lowering, coastal
flooding is expected with each daytime high tide cycle along
the Charleston and Colleton County coasts.

&&

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

&&

$$