-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 242133
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
533 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/...
Sfc high pressure is currently centered over the eastern Great
Lakes and extends east into New England south into the southern
Appalachians. Hurricane Maria is gradually pushing nwd N of the
Bahamas and well of the NE coast of FL. Locally, the sky remains
clear this afternoon (except for some wispy high clouds) under
the influence of high pressure. The high will remain nearly
stationary through tonight as Maria slowly moves nwd. The srn
fringe of the high will begin to break down late tonight as
Maria continues to move nwd resulting in some increasing clouds
across SE VA/NE NC. Elsewhere, patchy fog is possible where the
sky remains mostly clear. Low temperatures are forecast to be in
the 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Maria continues to trundle nwd Monday with the deep layer high
remaining anchored N 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 SE VA/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 SE of Cape Hatteras by 12z Tuesday. Maria continues
to push N Tuesday, and perhaps slightly W of due N as the upper
low drops sewd across FL. Increasing moisture and some outer
banded features will result in 20-40% PoPs along and E of I-95
Tuesday, with 40-50% for coastal SE VA/NE NC. QPF 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 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 SE VA/NE NC (and coastal MD 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/VA 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 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 NW to
mid 60s SE Thursday night, and in the 50s to low 60s
Friday/Saturday nights.

&&

.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
Clear/mostly clear conditions expected thru this evening with a
NE wind of 5-10kt. High pressure remains anchored N of the
region tonight as Maria continues to track nwd. Mostly clear
this evening, with increasing clouds later tonight across SE
VA/NE NC with some MVFR cigs possible. Otherwise, patchy fog is
possible where the sky remains mostly clear overnight.

Outlook: Partly sunny to mostly cloudy Monday with a 10-15kt NE
wind. 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 NW Thursday/Friday and pushes Maria farther offshore.

&&

.MARINE...
-- Changed Discussion --
Hurricane Maria is located about 470 miles SE 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 SCA 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. SCA headlines have
been issued for Bay/Sound/Lower James for Mon/Mon night with
ongoing SCA 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 VA/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 SCA 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 E 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 N winds to diminish west to east late Wed night with
wind speeds remaining SCA 20-30kt Bay/Sound/Ocean/Lower James
into Thu. NNW 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.
-- End Changed Discussion --

&&

.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 VA/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 3-5 ft nearshore waves and
13-15 second swell persists.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...None.
NC...Tropical Storm Watch for NCZ015>017-102.
VA...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.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JDM
NEAR TERM...JDM
SHORT TERM...AJZ/JDM
LONG TERM...AJZ/JDM
AVIATION...AJZ/JDM
MARINE...BMD
TIDES/COASTAL FLOODING...AKQ