Myrtle Beach, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

430
FXUS62 KILM 221122
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
622 AM EST Sun Dec 22 2024

.SYNOPSIS...
Cold, dry air will remain into Monday as Arctic high pressure moves
across the eastern U.S. The high will move offshore late Monday as
a coastal trough develops off the Southeast Coast. This will lead
to clouds and rain chances beginning Monday night and continuing
into Tuesday. Rain chances will be low for the latter half of
the week as a wedge of high pressure lingers across the inland
Carolinas.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure will continue to build in from the
north/northeast through early Monday morning. Fairly good
agreement on highs today struggling to get into the lower to
middle 40s although the anticipated cold start may be a bit
muted based on current observations. Lows Monday morning are
expected to be the coldest of the recent air mass (middle to
perhaps lower 20s) but once again boundary layer winds
especially east of I-95 may have a significant say.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Arctic air retreats to the north through the period, with increasing
rain chances beginning late Monday night.

Surface high pressure will be centered over New England Monday
morning, extending southwest across the Mid Atlantic region and the
Carolinas. A coastal trough will begin to sharpen up south of Cape
Fear through the day, and expect mostly sunny skies early to give
way to increasing clouds from south to north through Monday
afternoon as weak isentropic lift develops. GFS/CMC/NAM remain
bullish in developing a weak surface wave off the SC coast early
Tuesday and passing it north off the coast of Cape Fear. Latest
guidance indicates the potential for 0.2-0.5" of rainfall late
Monday night into Tuesday afternoon, with the higher end of that
range closer to the coast. Plan to raise PoPs between the 06Z-21Z
Tuesday in line with a MOS consensus of 40-60%.

As mentioned in previous discussion, there remains some concern that
the arrival of precipitation late Monday night may coincide with an
hour or two of freezing temperatures across the northern tier of the
CWA...generally north of a line from Hartsville to Elizabethtown.
Confidence is not high enough to warrant inclusion of freezing rain
in the forecast at this time, but we`ll be watching this closely.

As the surface wave departs late Tuesday, the surface wedge holds on
across the Carolinas through Tuesday night.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A low amplitude 500 mb ridge will transit the area and move off the
coast Wednesday as a shortwave crosses the MS River Valley. The
shortwave will weaken when it moves east of the Appalachians as a
mid-level ridge begins to amplify along the eastern seaboard. The
ridge develops across the east coast through Saturday, which will
allow temps to rise back above climo Friday and Saturday.
Prospects for precipitation through the period appear to be
relatively slim, perhaps trending up just a bit by Saturday with
the possibility of some showers moving onshore in ENE flow.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Very dry atmospheric column will allow VFR conditions to
continue through the period.

Extended Outlook...VFR conditions are expected through much of the
extended period, though there could be restrictions due to clouds
and showers Monday night into Tuesday.

&&

.MARINE...
Through Sunday night...Almost a persistence forecast for the
coastal waters thanks to slow moving high pressure off to the
north/northeast. Wind speeds will be in a range of 15-20 knots
for the most part. Regarding seas...the range will be 3-5 feet
today trending back slightly to 2-4 feet by early Monday.

Monday through Thursday...Surface high pressure north of the
area will extend across the Carolinas Monday, producing NE flow
of 15-20 kt across the waters. A coastal trough will sharpen up
late Monday into Monday night sough of Cape Fear, with a weak
low expected to move north off the Cape Fear coast Tuesday
morning. Showers and isolated thunderstorms will be possible in
association with this feature before it moves north of the
waters by Tuesday evening. A Small Craft Advisory may be
required Tuesday as 6 ft seas are expected to develop in the
waters beyond 10 nm. Northerly flow will develop the wake of the
weak surface wave Tuesday night, becoming NE again Wednesday
into Thursday as a surface ridge remains wedged across the
inland Carolinas.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...None.

&&

$$

SYNOPSIS...ILM
NEAR TERM...SHK
SHORT TERM...CRM
LONG TERM...CRM
AVIATION...SHK
MARINE...SHK/CRM