Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 231432

Area Forecast Discussion
National Weather Service Wilmington NC
1032 AM EDT Sat Sep 23 2017

High pressure over the Great Lakes region will maintain warm and dry
weather over the Carolinas through the weekend. Hurricane Maria is
expected to move northward a couple of hundred miles east of the
Carolina coast Monday through Wednesday. Hazardous boating
conditions, strong rip currents, and large surf are all expected to
develop. A cold front may reach the area Friday, bringing cooler
weather for late next week.


As of 1030 AM Saturday...A Coastal Flood Advisory is now in effect
for a few hours in the downtown Wilmington and battleship area for
minor impacts associated with high tide early this afternoon. The
next high tide is not projected to have as large a tidal range, but
thresholds could be met again with tomorrow`s high tide in the early

Previous discussion...Fog/stratus along the coastal counties will
continue to erode with strong insolation today. Low pressure remains
off the Jersey shore while a ridge of high pressure from the Great
Lakes will dominate the area weather today with a rather dry column
expected to be in place through tonight. At H5 heights will continue
to slowly increase as some bridging occurs between the ridge NE of
Maria and the large subtropical ridge extending the Plains, MS
Valley, Great Lakes, and into New England. This pattern will keep
the unsettled weather primarily far south/southwest of this part of
the Carolinas. No major changes were made to the current forecast.
The threat for strong rip currents will continue as swells from
Maria impact the surf zone.


As of 300 AM Saturday...Closed 500 mb high pressure centered
over Pennsylvania on Sunday will bridge across to the Bermuda
High on Monday. This "bridging" process is occurring earlier
and more strongly than models were thinking several days ago,
and this has led to a westward trend in the predicted path of
Hurricane Maria as it moves northward. Where over the past
several days the storm was expected to follow 70 or 71 degrees
longitude as it passed by the Carolina coast, we`re now thinking
73 or perhaps even 74 degrees longitude is more likely.

The 500 mb ridge to our north will help sustain a subsidence
inversion between 4000-6000 feet AGL Sunday that will lower to
3000-4000 feet on Monday. The stable and dry air aloft will help
to keep weather conditions dry across the area both days,
although it`s possible a few shallow maritime showers could
push onshore into the Cape Fear area by Monday night,
particularly if Maria moves as far west as some of the latest
models are suggesting. Early morning low stratus is also a good
possibility in this pattern.

Despite two days of northeast flow 850 mb temps shouldn`t fall
appreciably from where we`ve been over the past few days,
remaining in the +15C to +17C range. Our forecast highs range
from 83-86 near the coast to 86-88 both days. Overnight lows
generally 65-70, warmest at the beaches.


As of 300 PM Friday...Hurricane Maria will be slowly making its
way north well off the coast of the Carolinas through the first
half of the week. Expected impacts will be dangerous surf and
an elevated rip current risk from long period (15 sec) swells.
This swell energy will translate into breaking waves as high as
10 to 15 feet along the beaches of New Hanover and Pender
counties, and 6 to 10 feet along the beaches of Brunswick, Horry
and Georgetown counties into Wednesday. The swell energy should
begin to ease late Wednesday, but dangerous surf and an
elevated rip current risk will likely continue into Friday.

Northeast to north winds will be breezy along the coast, and
gust occasionally into the 20-30 mph range by Tuesday-
Wednesday. It will be a tough call at this point to determine
how much peripheral moisture from Maria will affect the area,
however it is reasonable to expect for the ILM CWA, that SE NC
will have the best chance for precipitation based on the current
forecast track of Maria. The highest PoPs, which will still
remain less than 30% at this time, will be Tuesday into
Wednesday, before the cyclone gets picked up by the westerlies
on Thursday as indicated by both the GFS and ECMWF.

Upper level ridging and subsidence west of the hurricane will
likely result in a sharp sky cover gradient and temperatures
remaining a few degrees above normal through the week.


As of 11Z...Fairly widespread low stratus and fog blankets the
area this morning, particularly inland from the coast. This
moisture is quite thin and should burn off quickly, with VFR
conditions developing around 13Z. The remainder of the day
should feature excellent aviation weather with mainly clear
skies and light northeast winds. Deep vertical mixing should
develop some shallow cumulus clouds with bases around 4000 feet
by noon, rising to 5000 feet later this afternoon. Clear skies
and light winds overnight may develop a little fog again late
tonight, but coverage should be much less than we are currently

Extended Outlook...Mainly VFR conditions through the period with
the exception of possible MVFR/IFR conditions due to low clouds
and fog each morning, mainly between 08z-12z.


As of 300 AM Saturday...A N-NE fetch is in place as high pressure
ridges southward across the coastal waters with speeds around 10
knots. Meanwhile, swells from Maria will continue to affect the
waters with seas in the 4-6 ft range. Although the dominant wave
period is 12-13 seconds the swells combined with the current
during times with a falling tide will create steep wave and
hazardous wave conditions in/near inlet entrances. Small Craft
Advisory will remain in place through the period.

As of 915 AM Saturday...1021 mb high pressure over the eastern
Great Lakes on Sunday will move off the New England coast by
Monday. Models have shifted farther west over the 24 hours with
Hurricane Maria`s track, now expected to move northward along
73 or 74 degrees west longitude next week. That`s a good 100
miles closer to the North Carolina coast than our thoughts were
this time last night, and could bring more of the peripheral
winds from Maria`s west side to the area. Gusts as early as
Sunday could reach 25 knots, and a Small Craft Advisory has been
extended out through Wednesday for increasing northeasterly
winds and for very large wave heights, particularly north and
east of Cape Fear where combined seas as large as 12 feet could
start showing up within 20 miles of the beaches by Sunday

As of 300 PM Friday...Based on the latest forecast track for
Maria, northerly winds will peak Tuesday night into Wednesday,
with 20 to 25 knots north of Cape Fear. South of Cape Fear, a 15
to 20 knot range can be expected. Expect Small Craft Advisory
conditions through the entire period.


SC...High Rip Current Risk until 8 PM this evening for SCZ054-056.
NC...High Rip Current Risk until 8 PM this evening for NCZ106-
     Coastal Flood Advisory until 2 PM EDT this afternoon for
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for AMZ250-



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