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000
FXUS62 KCHS 211500
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1100 AM EDT Sun Apr 21 2024

.SYNOPSIS...
An area of low pressure and associated front will push through
the area and offshore today. High pressure will then return to
the region and prevail through much of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Today: Latest surface analysis shows a cold front bisecting
Charleston, Colleton, Jasper, Bulloch, and Candler counties. A
weak surface low that was over Charleston county has pulled
northeast to off the NC coast. As a result the cold front that
was stalled north of Dorchester and Berkley counties earlier
this morning has oozed south. However, the front is likely to
not make it much further south early this afternoon. This is due
an approaching wave currently over MS/ AL. A 850 MB analysis
confirmed the presence of the wave and an stalled front across
the Midlands of SC. As a result of the FGEN forcing, widespread
rain has formed over the Upstate and Midlands of SC (the best
QPF being displaced just north and west of the surface feature
due to the Frontogenetical Circulation). At the surface, the
approaching wave will induce another weak surface low to form
near Hilton Head Island. As this occurs, a pseudo sea breeze/
warm front will push inland across Charleston County. There is
some concern that thunderstorms will initiate early this
afternoon and potentially become pinned along the coast and
produce heavy rainfall. Have upped PoPs along all coastal
counties to account for this.

Across the inland zones however, the FGEN forcing will head
northeast, or away from the region. Have lowered PoPs across the
inland GA zones, in particular.

Tonight: The front will be offshore by sunset. Shower activity
should end during the evening hours. High pressure will steadily
build into the area overnight. Lows will range from the upper
40s well inland and across the Francis Marion National Forest to
the lower-mid 50s elsewhere, warmest at the coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
High pressure will build inland on Monday in wake of a departing
front, before shifting overhead and eventually offshore through
mid week. Aloft, trough axis passes across the area with
building heights thereafter. Aside from possibly a few showers
right near the coast on Monday morning, the forecast is dry.
Temperatures will be warming with time as highs initially
unseasonably cool in the mid/upper 60s increase back to around
80 by Wednesday. Low temperatures spanning the 40s away from
Monday night gain a few degrees for Tuesday night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A cold front is expected to drop into the area Wednesday night
into Thursday with little impact. Otherwise, high pressure will
prevail, building from the north and then transitioning
offshore as we head into the weekend. Forecast remains dry
through the period, but its worth noting a couple models
indicate a few showers shifting onshore with a coastal trough on
Friday. Temperatures will be within a few degrees of normal.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
21/12z TAF Discussion:
KCHS/KJZI: Some passing light showers/sprinkles may impact KCHS
by 12z. No impacts are expected. VFR will prevail this morning
head of a cold front. Cigs will begin to lower by early
afternoon as a band of showers/tstms impacts the terminals.
TEMPO groups for MVFR vsbys/cigs in -SHRA are still favored,
roughly 19-22z for both sites. This is just about an hour faster
than the 06z TAF. While tstms could still occur, the better
instability looks to hold well to the south. No mention of TSRA
was included for this reason. The risk for IFR cigs will
increase around 00z with cigs lifting by late evening into the
early morning hours Monday. VFR should prevail by the end of the
12z TAF period.

KSAV: VFR this morning. Showers/tstms will be on the increase
this afternoon ahead of a cold front. A TEMPO group for MVFR
vsbys/cigs in TSRA is still favored, roughly 19-22z. Prevailing
MVFR cigs will then settle in as convection pushes offshore and
a cold front moves through. The risk for IFR cigs looks to hold
north of the terminal. VFR will return overnight as high
pressure builds in.

Extended Aviation Outlook: Flight restrictions will likely
linger into the first part of Monday before improving. VFR
thereafter.

&&

.MARINE...
Today: South to southwest winds will tip to the west and
northwest later today as a cold front approaches. Northwest
winds will surge to 15-20 kt by late this afternoon as cold
front moves into the coastal waters. Seas will average 2-3 ft.

Tonight: North winds 15-20 kt will be common behind the front.
Gusts to 25 kt will be possible, but the frequency will not
increase until closer to daybreak Monday as the pressure
gradient begins to tighten. Seas will build 3-4 ft nearshore
waters with 20 NM and 4-5 ft over the Georgia offshore waters.

Monday through Friday: Main time period of concern is on Monday
when gusty northeast winds and elevated seas are forecast over
the coastal waters. Confidence was high enough to hoist a Small
Craft Advisory for the outer Georgia waters, but this could
eventually be expanded to include at least portions of the
nearshore waters as well. Conditions should fall below advisory
criteria Monday night, with the exception of the outer Georgia
waters where 6 ft seas will linger a bit longer. Winds will
gradually turn to become more southerly by mid week as high
pressure shifts overhead then offshore, before the next front
drops into the area. Winds and seas are forecast to stay below
advisory levels through the end of the week.

Rip Currents: Gusty northeast winds and building seas will lead to
an elevated risk of rip currents on Monday. A Moderate risk is
currently forecast at all beaches.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 6 AM Monday to 2 PM EDT Tuesday for
     AMZ374.

&&

$$

NEAR TERM...Haines
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...