672
FXUS62 KILM 260800
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
400 AM EDT Thu Sep 26 2024

.SYNOPSIS...
Rain chances will increase through the day today with greater
impacts expected tonight into Friday morning as Helene passes
west of the forecast area, including moderate to heavy rain,
gusty winds, minor coastal flooding and isolated tornadoes.
Cooler and drier high pressure returns into next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Cloudy and slightly cooler today than yesterday. Highs in the
low to mid 80s. Light showers this morning will increase in
intensity and coverage this afternoon. Widespread showers and
storms will develop inland this afternoon over portions of
northeastern SC, primarily west of the Great Pee Dee River.
Breezy this afternoon with gusts up to 25 mph along the coast,
and up to 20 mph inland.

Winds increase tonight as Helene tracks across the southeastern
US. Onshore winds will peak around 20-30 mph along the coast
near midnight with periodic gusts up to 40 mph possible in some
of the stronger convection. Impacts from wind remain limited at
this time.

Convective rain bands do present some concern in the form of
tornadoes tonight. Fueled by warmer waters offshore,
instability will be strong enough for strong low level shear to
realize its potential offshore. As storms approach the coast,
there will be some degradation of the near surface lapse rates,
but the slight change of the near-surface environment will still
support tornadic potential over land. Tornadoes remain the
primary concern overnight, especially near the coast.

Heavy rain may also be a concern if a focused band of convection
sets for more than an hour or two, but the forward speed of the
storm and entrainment of dry air late tonight should
significantly limit this potential. Rain totals around 1-2
inches are expected with locally higher amounts up to 4 inches
possible. The best chance of higher totals will be in northeast
SC where convective bands could be more widespread earlier in
the day.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Remnants of Helene will pass NW of the area Friday into Friday
night. Early in the day at least, gusts up to 30-40 mph are
still possible before winds start to diminish midday into the
aftn. Similar trend for precip as well...with categorical PoPs
decreasing to chance/slight chance by the aftn as a dry slot
moves in from the SW around upr-level low pressure. Main threat
this period is isolated tornadoes Friday morning due to strong
low-level shear and helicity...SPC has almost the entire area in
a Slight Risk for severe storms (threat level 2 out of 5).

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Quieter weather returns for the long term period. Dry slot
wrapping around the upr-level low should allow for a dry
Saturday, before the low slowly shifts east through the local
area early next week and with increasing deep-layer moisture
will yield isolated to widely scattered showers and
thunderstorms. This feature moves offshore by midweek, giving
way to dry weather as weak sfc high pressure builds in from the
west. Temps close to climatological norms this period with highs
in the low/mid 80s and lows in the mid 60s to lwr 70s.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Primarily VFR overnight. Onshore flow could produce brief MVFR
CIGs at all terminals and a stray shower is possible inland
where convergence is increased. Unlikely to see meaningful PoPs
prior to sunrise. VFR to start the day, but conditions will
deteriorate during the evening and overnight Thursday. Rain
chances will increase late Thursday afternoon and into Thursday
night. Should see MVFR to IFR VIS and CIG. Winds increase
slightly with gusts up to 30 knots possible over SC terminals,
direction primarily out of the SE.

Extended Outlook... VFR should return through the weekend under
high pressure.

&&

.MARINE...
Through Tonight... Showers across the nearshore waters this
morning with winds 10-15 knots and gusts to 20 knots after
noon. Gradually deteriorating conditions are expected today with
gusts up to 25 knots arriving as early as late afternoon.
Conditions rapidly worsen this evening with a combination of
increasing convection and strengthening gradient winds. Tropical
Storm Warning for SC waters continues with SCA for NC waters.
Waterspouts will also be a concern, primarily after 00Z through
sunrise Friday. Seas 6+ feet by this evening will build up to
10-12 feet early Friday.

Friday through Monday... Hazardous marine conditions continue
into Friday as the remnants of Helene pass to the W then NW of
the local area. Expect gale-force gusts especially over the SC
coastal waters early Friday, with winds decreasing thereafter
Friday aftn through the weekend as Heline weakens and the
pressure gradient slackens. Sub-SCA winds expected by Friday
night, however 6 ft seas may linger into Saturday morning before
2-3 ft seas become the norm Sunday and Monday.

&&

.TIDES/COASTAL FLOODING...
Minor coastal flooding remains a threat for the next several
days, especially in NC. Minor flooding along the Lower Cape
Fear River will impact both sides of the river during the
afternoon high tides today. Onshore winds due to Helene are
expected to produce additional coastal flooding this evening
along the beaches as it moves northward from the Gulf of Mexico
through the southeastern US. Normal water levels should return
this weekend.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...High Surf Advisory from midnight tonight to midnight EDT
     Friday night for NCZ106-108-110.
     Coastal Flood Advisory until 7 AM EDT this morning for NCZ107.
SC...Tropical Storm Warning for SCZ017-023-024-032-033-039-054>056-
     058-059.
     High Surf Advisory from midnight tonight to midnight EDT
     Friday night for SCZ054-056.
MARINE...Small Craft Advisory from noon today to noon EDT Saturday for
     AMZ250-252.
     Tropical Storm Warning for AMZ254-256.
&&

$$

SYNOPSIS...ILM
NEAR TERM...21
SHORT TERM...MAS
LONG TERM...MAS
AVIATION...21
MARINE...MAS/21
TIDES/COASTAL FLOODING...