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094
FXUS62 KILM 131708
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
108 PM EDT Mon May 13 2024

.SYNOPSIS...
High pressure will move offshore today, allowing Gulf moisture
to spread northward. Widespread showers should develop late
tonight, joined by thunderstorms and heavy rain on Tuesday as a
wave of low pressure approaches. Scattered showers and storms
could continue through Wednesday, but dry weather is expected
Thursday as high pressure builds in. More rain chances could
develop Friday as the next storm system approaches.

&&

.UPDATE...
-- Changed Discussion --
Showers south of the area continue to develop and move closer to
the southern Pee Dee region. Expecting any showers that develop
this afternoon to be brief and light in intensity.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
A very broad storm system to the southwest will begin
to impact the area today and tonight. For today expect only some
cloud cover which could be quite variable at times. Still expecting
highs to check in around 80 degrees or so. Pops enter the equation
tonight via what appears to be very weak forcing focused inland.
Some instability warrants the continued inclusion of thunder as
well.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
A pair of shortwave troughs to our west and a 500 mb ridge just
off the Southeast coast will lift a deep stream of Gulf
moisture northeastward across the Carolinas Tuesday.
Precipitable water values should rise to 1.7 inches - not record
values for mid May but still in excess of the climatological
90th percentile. Isentropic lift embedded within a broad zone of
warm advection should lead to widespread clouds and showers and
forecast PoPs remain near 100 percent for Tuesday. The period
of heaviest rainfall rates should reach northeastern South
Carolina by late morning, spreading across southeastern North
Carolina early Tuesday afternoon.

Despite limited insolation due to thick clouds, unstable
conditions should develop Tuesday through advection of warm,
humid air at or just above the surface. GFS forecast soundings
suggest up to 500-1000 J/kg of CAPE could develop. Bulk shear
across the 0-6 km layer of 30-40 knots is sufficient to support
organized storms, and curvature in low level wind profiles
suggests enough helicity may be present to create a "non-zero"
tornado potential. HREF updraft helicity ensembles suggest this
threat may be highest Tuesday morning south of Florence and
Conway. The more widespread threat could be locally heavy
rainfall as up to three inches is forecast (storm total) in the
Georgetown area.

Mid level winds will veer more westerly late Tuesday
afternoon/early Tuesday evening as the first of two upper
impulses moves overhead. This will cause us to lose our
moisture connection to the Gulf and rain chances are expected
to decrease through the night.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The second upper impulse should slow down and crawl
northeastward across Kentucky and then the Mid Atlantic states
Wednesday and Wednesday night, finally exiting the coast early
Thursday. Enough sunshine should develop Wednesday to steepen
lapse rates and generate CAPE of 1500-2000 J/kg. Enhanced
westerly flow south of the upper disturbance will increase shear
values enough that we`ll need to watch for a series of fast-
moving convective clusters during the afternoon hours that could
lay down strong, gusty winds. Forecast PoPs remain 50 percent
or higher for all but Williamsburg and Georgetown counties.
Convective activity should quickly wane with loss of heating
Wednesday evening.

High pressure should build southward across the area Thursday
and Thursday night with dry weather expected.

Models differ on the shape of the upper system approaching late
in the week, but the next shortwave trough moving into the
eastern half of the country should pull Gulf moisture northward
again by Friday afternoon with scattered showers or storms again
becoming possible. This system should move offshore by Saturday,
but uncertainty increases rapidly for Saturday night into Sunday.

&&

.AVIATION /17Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Low level Cu will increase this afternoon in onshore flow. A
few brief showers are possible, but restrictions are not
expected (brief MVFR if any occur). High clouds increase
overnight with lowering ceilings through Tuesday morning. MVFR
conditions are expected everywhere after midnight with showers
increasing from south to north through sunrise. A few areas of
IFR are possible inland near sunrise, but confidence is low in
the warm advective regime in holding on to a solid IFR
restriction through Tuesday. More likely to be a variation of
VFR/MVFR/IFR in periods of heavy rain through late Tuesday.

Extended Outlook...Flight restrictions may occur Monday night
into Tuesday with the next weather system moving in. Improving
conditions into Thursday. Another system approaches the area for
next weekend.
-- End Changed Discussion --

&&

.MARINE...
Through Tonight...After several quiet days the coastal waters will
see increased winds and eventually seas via an extensive storm
system to the south west. Light winds from the southeast will
increase to the higher end of a 10-15 knot range by Tuesday morning.
Significant seas will see an increase as well from the current two
feet to a healthy range of 2-4 feet.

Tuesday through Friday...Mariners are in for difficult weather
conditions at times this week. Moderate to strong south winds
are expected to develop Tuesday as a warm front lifts north
across the area. Widespread showers and a few thunderstorms
with heavy rain are expected during the day. Winds and seas will
likely reach Small Craft Advisory thresholds.

Showers may continue through Tuesday night as a wave of low
pressure moves northeastward across the Coastal Plain just
inland from the beaches. A cold front following behind the area
of low pressure should push offshore Wednesday, however
unsettled weather conditions including shifting wind directions
and periods of showers and thunderstorms may linger into
Wednesday evening before high pressure finally builds across
the Carolinas Thursday into Friday.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...Small Craft Advisory from 11 AM Tuesday to 9 AM EDT Wednesday
     for AMZ250-252.

&&

$$

SYNOPSIS...TRA
UPDATE...21
NEAR TERM...SHK
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...21
MARINE...TRA/SHK