Scientific Forecaster Discussion
fxus62 kilm 162353
Area forecast discussion
National Weather Service Wilmington NC
653 PM EST Sat Nov 16 2019
periods of rain, very strong wind, and unseasonably cool
temperatures will prevail through the remainder of the weekend,
as powerful low pressure deepens off the Carolina coast. The
storm will move away from the area late Sunday, with rain and
wind trending down. High pressure will follow early next week,
with drier and warmer weather into mid week. A cold front is
expected to move through the area late next week.
winds: almost all synoptic/mesoscale models show the strongest
975 mb winds (45-50 kt) affecting the coast between now and
06z. The Frying Pan Shoals buoy has gusted to 58 kt/67 mph
within the past hour. Gusts on the beaches have reached 59 mph
at Wrightsville Beach, and 45 mph on Topsail Island. Weatherflow
Station Peak gusts include 51 mph at Federal Point, nc; 49 mph
at Oak Island, nc; and 48 mph at Lake Arrowhead near Myrtle
Beach, SC. At the Wilmington Airport gusts have reached 47 mph,
with 46 mph at North Myrtle Beach. The Wind Advisory was earlier
expanded one tier of zones westward, and continues into Sunday.
Temps: temps may rise a bit along the NC coast overnight, with
steady to slowly falling temps anticipated across most of
northeastern South Carolina. Forecast lows are raised to around
40 on the I-95 corridor, mid 40s SC beaches, and upper 40s NC
beaches. Used a raw model-based curve (non-diurnal) to calculate
hourly temps through Sunday morning.
Probability of precipitation/wx: used 18z NAM and 22z hrrr to nudge pops/wx grids
overnight. Inland rain should largely dry up around midnight,
but waves of rain and some evening elevated convection will
continue overnight nearer to the coast. Overall reduced quantitative precipitation forecast
forecasts, especially inland.
Coastal flooding: expanded the coastal flood advisory to cover
the Brunswick County coast. Despite offshore winds, the offshore
storm has pushed water levels high enough along the entire
Carolina coastline to produce flooding during Sunday morning's
high tide. This is one to watch: the latest etsurge guidance has
Wrightsville Beach getting within about 3 inches of moderate
(warning-level) coastal flooding Sunday.
Near term /through Sunday/...
high surf advisory for Pender, New Hanover beaches ongoing through
much of Sunday, as 8-13 foot breakers crash onshore. This threat
will escalate with Sunday morning's high tide, as coastal flooding
and high water run-up reach peak, increasing the danger for
beachgoers, especially anyone entering the surf, or venturing too
close to the surf's edge without a flotation device.
Strong winds caught in the pressure grip of the potent coastal low
will peak this evening, holding strong overnight, with more notable
abating of wind Sunday afternoon. As a result the 'wind advisory'
for the NC coast will remain intact, with north gusts as high as 45-50
mph from Surf City to Wrightsville Beach to Carolina Beach to Fort
Fisher to Bald Head Island, to eastern Brunswick County coast
tonight and early Sunday. Weakened trees or large branches from
hurricane dorian's impacts could topple as winds peak late today,
overnight, and early Sunday morning.
Approximate Center-Line of qpf ensembles, pointing to an additional
1.5-2 inches along the NC coast, 3/4-1.25 inches along the NE SC
coastal zones, and 1/3-1 inch for most of inland southeast NC and NE SC.
Areas west of I-95 may only see additional amounts around 1/4 inch.
Do not anticipate big flooding problems, but isolated training of
rain, or brief high rain-rates, could cause localized flooding, and
dangerous water ponding on highways.
Wind, clouds, rain, and a singular air mass, will keep temperatures
at and by the coast, nearly flat-lined, whereas diurnal temperature
ranges well inland will show greater spreads between
Short term /Sunday night through Monday night/...
a mid level trough will move across the area through the day
Monday and guidance, although seemingly going back and forth is
once again developing some light showers across the area. Have
added little activity (pop) with this development and to align
with adjacent offices as well. Highs Monday will be in the
middle to upper 50s and lows Tuesday morning with some clearing
will be a couple of degrees either side of 40.
Long term /Tuesday through Saturday/...
the extended period remains relatively unchanged with the mid
level trough moving across early in the week transitioning to a
somewhat progressive mid level ridge. A broad split flow wants
to develop late although there are timing differences with the
guidance. A cold front, mainly associated with the northern
branch moves across very late in the period. Not necessarily a
significant system but low pops are warranted. No significant
changes to the temperature forecast which offers little
deviation from climatology until late when warmer readings
Aviation /0z Sunday through Thursday/...
predominantly MVFR this taf period, with chance for IFR ceilings
overnight into tomorrow morning. As strong Nor'easter offshore
slowly moves northeastward, abundant low level moisture and tight
pressure gradient will keep ceilings mainly around 1500 ft across
the area with strong northerly winds. Light rain will slowly
taper off across NE SC, and linger in coastal NC areas through
tomorrow afternoon. Included IFR ceilings at ilm overnight where
confidence is higher, but IFR possible elsewhere as well.
Strongest winds will be between now and 12z, sustained between
15 and 20 kts inland and 20-25 kts along the coast, with gusts
mainly between 25 and 30 kts. Gusts up to 40 kts at times possible
at coastal sites overnight. Have included low-level wind shear
at ilm due to forecasted winds at 2 kft over 50 kts overnight.
Wind shear at myr and cre will be close to criteria with 2 kft
winds near 50 kts.
Extended outlook...sub-VFR ceilings could linger Sunday into
Monday afternoon, mainly along the coast and southeast NC. Becoming
VFR Monday through Thursday, with chance for fog Tuesday morning.
dangerous marine conditions, venturing out and especially offshore
is highly discouraged. Storm force winds will rip across the NC
waters and buoy 41013 has already reported gusts to 51 knots, or
about 59 mph. Gale force winds will Rake the SC waters, with a few
storm force gusts possible beyond 15 nm tonight and early Sunday.
Noticeable lessening of winds will be seen by Sunday afternoon, but
still dangerous as large seas propagate through the waters. Seas
made up of NE waves 9-14 every 10-12 seconds, with lashing north chop in
the mix on top of these large waves. If all this were not convincing
enough to stay in port, isolated tstms are possible offshore, mainly
beyond 10 nm through this evening.
No real significant systems to drive winds and seas too high
for basically the short and long term period. More variability
in the winds, which is typical if anything. A decent northwest
flow of 10-15 knots will be in place initially associated with
the waning impacts from this weekend's coastal storm. Weak high
pressure will dominate the mid week period with a weak boundary
moving across later Tuesday to kick up the winds briefly. A
decent and prolonged (at least for the winter season) return
flow develops late and increases gradually in magnitude. Could
see some 15-20 knot speeds here. Significant seas basically
follow the winds with 2-4 feet with maybe an increase late with
the better fetch.
dangerous beach conditions through Sunday morning. Tidal flooding
will combine with large storm-waves, to bring significant coastal
flooding and sea-water run-up at areas beaches. The offshore wind at
Brunswick County will help Stem The Reach and advance of water
there, and to a lesser extent at east facing beaches.
Erosion will occur Sunday morning, as water levels approach the more
rare 'moderate' flooding threshold, possibly breaching low dune
spots, with exception of Brunswick County. Right now, predicted
water levels to make the upper reaches of 'minor' category, but this
could change to moderate with any increases in predicted levels.
The lower Cape Fear River also to experience significant water rises
Sunday morning, especially with all the rain run-off, and river
levels also approach moderate stages, resulting in much more
extensive impacts to residents affected by high water levels on the
lower Cape Fear River, and adjacent roadways.
SC...Wind Advisory until noon EST Sunday for scz054.
Coastal flood advisory until 2 PM EST Sunday for scz054-056.
NC...Wind Advisory until noon EST Sunday for ncz105>110.
High surf advisory until 6 PM EST Sunday for ncz106-108.
Coastal flood advisory until 2 PM EST Sunday for ncz106-108-
Coastal flood advisory from 10 am to 2 PM EST Sunday for
Marine...Gale Warning until noon EST Sunday for amz254-256.
Storm Warning until 6 am EST Sunday for amz250-252.