Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 281739

Area Forecast Discussion
National Weather Service Wilmington NC
139 PM EDT Wed Sep 28 2016

A cold front approaching from the west will stall through mid-
week before moving across the area Thursday into Friday. Dry high
pressure will build into the area by the weekend.


As of 1000 AM Wednesday...Anomalously strong upper low centered near
Lake Michigan will deepen and sink slowly SE through tonight.
Beneath this feature, a stationary front will meander across
western/northern NC and into VA, keeping the local area firmly
within the warm sector today. While this will create temperatures
well into the 80s this aftn, about 5-8 degrees above normal for late
September, it will also allow humidity to increase and create an
environment ripe for convection.

SPC has placed the i-95 counties in a MRGL risk for today, and while
total storm coverage is not expected to be widespread, any
individual storms will have the potential to produce a strong wind
gust. The combination of warm temperatures and high humidity will
drive SBCape to 2500 J/kg, which will combine with subtle height
falls, PWATS to 1.5 inches, and 20-25 kts of 0- 6 km shear to
produce that aforementioned isolated strong wind threat. Highest POP
will be featured along and west of i-95, which is agreed upon by
both the HRRR and NSSL 4km WRF, and makes sense as it is closest to
the upper low and along a moisture gradient. Heavy rain will also be
possible in stronger storms, but motion should be great enough to
prevent any significant flooding unless several storms pass across
the same area.

This evening and tonight, a shortwave will move out of the gulf
along the periphery of the upper low and overhead the CWA. This will
likely bring the best chance for showers with isolated tstms to the
eastern portion of the CWA, but no severe is expected tonight. Mins
will remain above normal for the time of year, dropping only to
around 70.


As of 345 AM Wednesday...Of the 2 days, Thu will be the wetter of
the 2 and exhibit the higher POPs. The main feature will be the
cutoff low making its furthest southern positioning across the
Central Appalachians. Thursday will feature embedded and stronger
mid-level s/w trofs rotating around this cutoff low. The one Thu
morning moves NE of the FA with the eastern 1/3 to 1/2 seeing
ongoing convection at the start of the day, moving out of the FA by
late morning. The next s/w rotating around and closer to the cutoff
low, will help push a dry slot across portions of the FA late Thu
aftn and night. With it not entirely thru the FA, will keep a POP
for the far eastern portions of the ILM CWA Thu night into Fri.
Finally, the models indicate the dry slot will finally shunt the
remaining moist air off the Carolina coasts by late Friday.
Improving wx conditions across the FA during Fri into Fri night.
Max/Min Temps, stayed closer to a consensus with a lean toward the
MET mos guidance based on its decent performance the past couple


As of 3 AM Tuesday...Despite the fact that the long term begins with
an impressively large cutoff to our west the weather will be pretty
quiet. The reason for this is that we will be in the dry slot of the
occluded surface low to our NW and the deep moisture will be off the
coast. Sunday and Monday as the weakening front pushes through some
of this moisture may get drawn back to the coast for some minor rain
chances-all while temperatures remain close to their seasonable
norms. The front washes out by Monday leaving behind a weak surface
pattern while mid level heights build. There will still be no real
forcing for precipitation and no low level thermal advection to
change temperatures much from the values earlier in the period.


As of 18Z...VFR conditions this afternoon and evening outside of
SCT 3SM TSRA BKN030CB across inland terminals KLBT/KFLO BTWN
22-02z. Isolated showers throughout region aft 02z as disturbance
aloft moves north over interior zones and ocean showers move
onshore at coastal terminals overnight into very early Thursday.
VFR Thursday 13z-18z as drier air spreads into the region with SKC
for most locations, TCU at end of TAF cycle.

EXTENDED OUTLOOK...Primarily VFR. Isolated to scattered afternoon
showers through much the period, although limited in strength and
coverage due to dry air aloft.


As of 1000 AM Wednesday...Stalled front will remain NW of the waters
today, with a weak pressure gradient persisting. Winds currently
around 5 kts will become SE at 5-10 kts, and may increase further to
10-15 kts late tonight with continued veering to the SW. This will
create seas of 2-3 ft through the near term, with a Southerly wind
wave and low amplitude SE swell comprising the spectrum. Showers
with isolated tstms will be possible across the waters late tonight
as well.

As of 345 AM Wednesday...Sfc pressure pattern and a tightening-
some of the gradient, will result in SW winds at 10 to around 15
kt thru this period. Significant seas will run 2 to 3 feet with 4
footers possible Wed and Thu when winds will be closer to 15 kt
sustained due to the semi-tightened sfc pg. Wavewatch3 and local
Swan keeps the ESE 11 second period ground swell affecting the
local waters but with some degradation. Local wind driven waves at
4 to 6 seconds will become the more dominant feature of the
significant seas by late Thu thru Friday.

The sfc cold front will finally push to the Carolina coasts
during Friday, and stalling just offshore the ILM Waters Friday
night. The dry slot or tongue will push across the waters late
Friday ending the threat for showers and thunderstorms.

As of 3 AM Tuesday...A weakening cold front running parallel to
the coast will only slightly shift through the period moving from
just onshore to just offshore. It`s parent surface cyclone will be
well occluded and thus deprived of its energy source and so the
whole system will feature a baggy and poorly defined pressure
pattern. This is good news for most mariners though as winds will
be quite light and somewhat variable through the period. Seas will
be slightly elevated above what such slack winds would otherwise
support since spectral wave bulletins show a myriad of wave





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