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Area forecast discussion
National Weather Service Wakefield Virginia
838 PM EDT sun Sep 24 2017

Synopsis...
high pressure will prevail across the mid Atlantic through
Monday. Meanwhile, Hurricane Maria will gradually track North
Well off the southeast coast. Maria is forecast to approach the
Outer Banks Tuesday into Wednesday, before pushing farther
offshore Thursday ahead of an approaching cold front late in the
week.

&&

Near term /until 6 am Monday morning/...
not much has changed in 24 hours as high pressure remains
ivof the Delmarva with cirrus moving northward well ahead of
Maria. Generally mostly clr overnight with some patchy fog
possible away from the water after midnight. Lows in the mid to
upper 60s.

&&

Short term /6 am Monday morning through Wednesday/...
Maria continues to trundle nwd Monday with the deep layer high
remaining anchored north of the region. Some outer bands of the
tropical cyclone will result in partly to mostly cloudy
conditions along the coast, with partly to mostly sunny
conditions farther inland (w of I-95). Deep layer moisture
remains limited with only a slight chc pop for coastal NE NC. A
modest tightening of the pressure gradient will result in a ~15
mph NE wind across coastal southeast Virginia/NE NC with gusts to ~25 mph.
High temperatures will remain above normal ranging from the
upper 70s to around 80f at the coast to the mid/upper 80s
farther inland.

There is decent model agreement showing Maria reaching about
175-200mi southeast of Cape Hatteras by 12z Tuesday. Maria continues
to push north Tuesday, and perhaps slightly west of due north as the upper
low drops sewd across Florida. Increasing moisture and some outer
banded features will result in 20-40% pops along and east of I-95
Tuesday, with 40-50% for coastal southeast Virginia/NE NC. Quantitative precipitation forecast will be
minimal for most areas. Lows will generally be in the mid 60s
to low 70s Tuesday night, with highs in the upper 70s to low 80s
Tuesday under a mostly cloudy sky. Becoming breezy along the
coast with a NE wind increasing to 15-25 mph along the coast
Tuesday, with gusts up to 30-35 mph possible.

The latest 12z European model (ecmwf) still brings Maria about 50 miles closer
to the NC Outer Banks on Wednesday compared to the 12z GFS. Will
defer to NHC on the exact forecast track as of 5 PM, but
indications are that a shift a bit farther to the west may be
warranted. This will in turn further increase the potential for
some rainfall across southeast Virginia/NE NC (and coastal Maryland to a lesser
degree), somewhat stronger wind gusts at the coast, higher
seas, and at least minor to moderate coastal flooding. At this
time, still don't anticipate heavy rain along the coast, generally
less than two inches, given Maria's offshore track. Will have
pops of 30-60% east of I-95 Wed, with slight chc pops into the
Piedmont. Wind gusts could reach 40-50 mph from around
Norfolk/Virginia Beach southward into coastal NE NC where tropical
headlines may eventually be needed. The biggest impacts will
likely be from tidal flooding and beach erosion along/near the
coast. Highs Wed from the upr 70s coast to the low/mid 80s
inland.

&&

Long term /Wednesday night through Sunday/...
first part of the extended, Wednesday night through Thursday,
will be predicated on future track of Hurricane Maria. Have
utilized superblend for tangible weather during this period,
given potential uncertainty in the track. Again, will stress
that the 12z European model (ecmwf) is ~50 miles closer to the coast than the GFS
and have weighted the forecast more toward its solution for the
extended. This would linger Maria closer to the NC obx through
Thursday before eventually taking Maria fairly quickly
northeastward away from the area on Friday in advance of an
upper trof dropping southeastward from Canada. This trof and
associated cold front move into the region next Saturday.

Above normal temperatures continue on Thursday, with highs from
the upper 70s to mid 80s. Temperatures cool into the 70s
Friday/Saturday in the wake of Hurricane Maria. Lows Wednesday
night range from the mid 60s to around 70f, then mid 50s northwest to
mid 60s southeast Thursday night, and in the 50s to low 60s
Friday/Saturday nights.

&&

Aviation /01z Monday through Friday/...
VFR conditions across the region at 00z with increasing high
clouds from Maria moving into the Carolinas and southern
virginina. NE winds 5 to 10 kts overnight will become gusty
15-20 kt by early to mid morning. High pressure remains anchored
north of the region tonight as Maria continues to track nwd.
Increasing clouds late tonight across southeast Virginia/NE NC will bring
some MVFR cigs for ecg in the morning and IFR conditions by the
aftn/evening. Patchy fog is possible for phf and sby again
overnight.

Outlook: increasing moisture and some distant banding from
Maria will result in a 40-50% chc of showers for orf/ecg and
20-40% for ric/sby/phf. Conditions Tuesday
night/Wednesday/Wednesday night will largely be dictated by how
close Maria gets to the Outer Banks. A closer approach will
result in breezy to windy conditions, especially at orf/ecg
along with an increased chc of rain and degraded flight
conditions. A cold front approaches from the northwest Thursday/Friday
and pushes Maria farther offshore.

&&

Marine...
Hurricane Maria is located about 470 miles southeast of the SC/NC
border as of 400 PM. Meanwhile, high pressure remains centered
north of the area tonight as Maria starts to take more of a
northward track. NE winds average 10-15kt overnight with long
period onshore swell allowing seas to average 4-5ft north/5-8ft
south. Gradient winds between high pressure to the north and
Maria to the south will steadily increase Mon into Mon night...
reaching Small Craft Advisory conditions (ne 15-30kt)during this time for srn
coastal waters, Currituck Sound, srn ches Bay, and the lower
James River. Seas build ahead of maria: nrn waters 5-6ft Mon
aftn...building to 6-8ft late Mon night. Srn waters 6-8ft Mon
aftn...building to 8-10ft late Mon night. Small Craft Advisory headlines have
been issued for Bay/sound/lower James for Mon/Mon night with
ongoing Small Craft Advisory for hazardous seas for all coastal waters during
this time.

Latest 12z model guidance (as well as the official NHC forecast)
still keeps Maria offshore of the Carolinas Tue/Tue night and
off the mid Atlantic coast Wed into Thu. NE winds continue to
increase during this timeframe with the strongest winds
expected to occur Tue night into Wed morning. Tropical storm
conditions will be possible for srn Bay, sound, and coastal
waters from Chincoteague to Currituck light with wind gusts
ranging from 35-45kt (up to 50kt possible far srn coastal
waters). A tropical storm watch has been issued for Currituck
Sound and srn waters from the Virginia/NC border to Currituck light
until 12z/800 am Thu morning. Aforementioned areas above may
be added to the watch as late as Mon aftn since impacts farther
north of the watch area are not anticipated to begin until Tue
evening. Elsewhere, strong/solid Small Craft Advisory conditions (20-30kt) will
occur. Seas build as high as 15-17ft south and 11-16ft north
during peak wave heights on Wed as Maria is currently expected
to be centered about 175 miles east of Duck, NC. Maria should
start to drift eastward Wed aftn/early evening and move away
from the coast Wed night...getting pushed out to sea on Thu.
Adverse north winds to diminish west to east late Wed night with
wind speeds remaining Small Craft Advisory 20-30kt Bay/sound/ocean/lower James
into Thu. North-northwest swell behind departing Maria will keep seas
elevated while being very slow to drop to 6-10ft north and
7-11ft south by late Thu aftn.

Please monitor the NHC forecast for the official forecast
track of Hurricane Maria.

&&

Tides/coastal flooding...
tidal departures had decreased some this afternoon averaging
1.0 ft above normal Tide. Water levels remain elevated with some
nuisance flooding still occuring in the Bay and rivers,
however, water levels remain below minor flood thresholds. Will
need to watch for additional flooding by mid week, especially
later Tue and Wed (and perhaps thu). This will depend on the
exact track of Maria, but the potential for significant tidal
flooding reaching moderate to even major levels exists
(especially over locations adjacent to the Lower Bay and
southern Virginia/NE NC waters). High surf advisories likely will be
needed by Tue lasting into Wednesday and Thursday. The
combination of storm surge and large waves could result in
significant coastal erosion and damage to dune structures mid
week.

High risk for rip currents for all beaches adjacent to coastal
waters continues through today, as 4-5 ft nearshore waves and
13-15 second swell persists.

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...tropical storm watch for ncz015>017-102.
Virginia...none.
Marine...Small Craft Advisory from 1 PM Monday to 6 am EDT Tuesday for
anz632-634-638.
Tropical storm watch for anz633-658.
Small Craft Advisory for hazardous seas until 6 am EDT Tuesday
for anz650-652-654-656.

&&

$$
Synopsis...jdm
near term...jdm/mpr
short term...ajz/jdm

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