147
FXUS62 KILM 250906
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
506 AM EDT Wed Sep 25 2024

.SYNOPSIS...
High pressure to prevail through today with generally low rain
chances. More unsettled weather is expected later Thursday
through Friday as Tropical Cyclone Helene passes west of the
forecast area. Nevertheless, look for possible impacts such as
heavy rain, gusty winds, coastal flooding and isolated
tornadoes. Cooler and drier high pressure should then return
later in the weekend into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Ridging to the east and an upper low to the west will maintain
warm advective flow across the area today. Dry air aloft will
maintain mostly clear skies and will also inhibit meaningful
destabilization. Shallow showers will be possible, mainly
inland, this afternoon. Have held PoPs around 20%. SE winds
increase slightly overnight and temperatures remain mild. Lows
in the lower 70s near the coast, around 70 inland.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Main story for this period will be the effects from Tropical
Cyclone Helene as its circulation expands/grows prior to making
landfall across the Florida Pan Handle Thu evening. Look for
conditions to deteriorate during the day Thu from south to
north as a swath of moisture, ie. rainband, moves up the coast
and pivots inland. The worst of the conditions, wind, heavy
rain, threat for tornadoes to occur late Thu afternoon
thru Fri morning. As mentioned AFDs prior, PWs upwards of 2.25+
inches, and therefore when all said and done, widespread 1 to
2 inches of rainfall possible, locally higher amounts possible
especially across the ILM SC CWA. Fri aftn thru Fri night,
should see improving weather conditions

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Helene, or the remnants of, will get caught up in an upper
cutoff low across the Mid Mississippi River Valley by Sat. Dry
air rotating around the upper low, will push across the area
Sat. Will be a warm day, with some clouds but only isolated
convection possible with widespread mid to upper 80s and a few
90 degree readings possible. The sfc pg will relax quite a bit
by Sat, with generally light SW winds expected. Models indicate
the upper low to fill as it drops toward the ESE, reaching the
FA by early next week. More clouds and scattered showers and
possibly an isolated tstorm, expected both Mon and Tue, and
mainly diurnally driven each day with the aid of the colder
temps aloft. Should see temps drop at or just below normal
the 2 days next week.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Low confidence in IFR CIGs inland overnight as warm advective
flow increases aloft. Some periodic low clouds are developing at
the moment, but boundary layer winds and low level mixing will
likely keep CIGs widely scattered. Onshore flow near the coast
may maintain some threat of MVFR through sunrise. Warm advective
flow will keep VFR conditions across the area today. A few
showers will be possible prior to sunrise inland.

Extended Outlook... VFR conditions expected outside of predawn
fog and stratus. Helene will likely pass west of the area
Thursday night through Friday bringing a high chance for
restrictions and gusty winds.

&&

.MARINE...
Through Tonight...Southerly flow today will increase this
evening as a surface low (what will become Hurricane Helene)
deepens over the Gulf of Mexico. Winds around 10-15 knots this
afternoon will increase to 15-20 knots tonight. Seas gradually
build today from 2-3 feet to 3-4 feet. Widespread seas of 3-5
feet could develop before daybreak on Thursday.

Thursday through Sunday Night...SCA thresholds to be met by noon
or during the early afternoon. SE winds to increase thruout the
day driven by Tropical Cyclone Helene`s increased circulation
especially the wind radii on the eastern semi-circle. Thu will
see the modest 11+ second period ENE Swell interact with the
building SE wind driven short period waves. Will observe 6
footers commonplace by or during Thu afternoon. Gale Force
gusts threat to primarily occur from Thursday evening thru
midday Fri. Seas will peak in the double digit low teens during
the mentioned period. Showers, storms with heavy rain and the
threat for waterspouts can be expected from midday Thu through
early Friday as the main swath(band) of moisture moves from
south to north, up the Carolina coasts. Winds and seas should
start to subside late Fri into Sat as winds go nearly offshore,
with sub-SCA conditions returning for the latter 1/2 of the
weekend.

&&

.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 through Thursday. However, Helene is
forecast to be a large storm and onshore winds could produce
additional coastal flooding for each successive high tide
starting on Thursday afternoon 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...Coastal Flood Advisory until 7 AM EDT this morning for NCZ107.
SC...None.
MARINE...Small Craft Advisory from noon Thursday to noon EDT Saturday
     for AMZ250-252-254-256.

&&

$$

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