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fxus61 kakq 151230 

Area forecast discussion
National Weather Service Wakefield Virginia
730 am EST Fri Nov 15 2019

low pressure off the southeast coast today will intensify while
tracking northeast off the Carolina coast Saturday into Sunday.
Meanwhile, strong high pressure will become centered over the
Great Lakes on Saturday, and will shift east to New England by


Near term /through tonight/...
as of 715 am EST Friday...

Latest analysis indicates a deepening trough of low pressure
along the coast of northern Florida/GA/SC, extending NE to well off
the se Virginia coast. A moist west-southwest flow prevails aloft and WV/infrared
satellite imagery depicts ample cloud cover all the way to the
mid Atlantic region. An area of showers is passing across southeast Virginia
and will gradually get shunted to the S later this morning but
there are still some areas of light rain extending back into
Southside Virginia so have extended chance pops there through 15z.
Scattered to numerous showers will impact the southeast portions of
the forecast area throughout the day, with moderate to heavy
rain possible at times across far southeast Virginia and NE NC by late this
aftn and into the evening. Precip will likely have a somewhat
sharp cut off to the northwest as the low off the coast gets better
developed and the precip will be battling dry air from a strong
high pressure over the Great Lakes region. High temps will
remain cool, ranging from the mid 40s over interior southern Virginia
in weak low level wedging, with 50-55f over the far southeast and upper
40s/lower 50s in the far north (with some breaks in the clouds and
little to no chance for rain). Continued with likely to
categorical pops southeast tapered to a dry forecast northwest tonight. Lows
in the 30s northwest to the upper 40s southeast.


Short term /Saturday through Sunday night/...
as of 345 am EST Friday...

Low pressure strengthens Saturday into Sunday off the coast.
Meanwhile, the strong high pressure will move from the Great
Lakes region to over northern New England by Sunday. Have raised
pops across the southeast zones to likely/categorical Sat through sun
am, but there will again be a tight gradient in moisture from
southeast to northwest such that northwest sections of the County Warning Area will see some breaks
in the clouds and little to no chance for rain during this
period (due to drier air filtering in from the north). A
tightening pressure gradient will create strong gusty winds
along the coast. North/northwest winds will gust 40-60 mph near the coast
of southeast Virginia and high wind warnings with a Wind Advisory buffer zone
a little farther inland has been issued. Rain should begin to
wind down by late Sunday as the low continues to move NE and
pulls well away from the coast, however some lingering scattered
showers may still be around along the coast into Sunday night.
High temps Saturday and Sunday will be in the 40s for most to
50s across the far se, with low temps ranging from the 30s northwest to
mid 40s southeast. Rainfall totals through Sunday night will likely be
2-3 inches across NE NC, 1-2" far southeast Virginia with lesser amounts as
you move northwest. The far northwest of the forecast area likely won't see
any rain or just a few hundredths during this event.

*Note that the past 2 runs of the NAM have been outliers
depicting a double barreled sfc low off the coast and bringing
heavy precip well inland to the Piedmont. With corresponding
lower thicknesses, the NAM continues to show freezing rain and snow late Sat
night/sun am. Given the more consistent GFS/European model (ecmwf) with a single
sfc low offshore during this period, the NAM has been


Long term /Monday through Thursday/...
as of 345 am EST Friday...

By Monday, a consensus forecast has the coastal low slowly moving
north-northeast offshore, up the mid- Atlantic waters to the northeast and
eventually the Canadian Maritimes by Tuesday, though there are
some model differences with respect to how fast this occurs.
Also, 00z/15 GFS/European model (ecmwf) and their ensembles have another upper
trough quickly moving in from the Tennessee/lower Ohio Valley Mon aftn
into Mon evening. Will generally have a slight chance of
showers in the forecast across mainly the NE early Monday with
the potential for some increase in pops to ~30% most areas later
Mon/Mon evening with the upper trough. For Tue and beyond, lower
confidence in the forecast as the models have yet another upper
trough into the deep south and crossing into the region. This
will bring the possibility for the development of another
coastal low off the Carolina coast late Tuesday into Wednesday,
but both the latest GFS and European model (ecmwf) runs keep this feature well
offshore. Regardless, the region (eastern portions in
particular) may feel some impacts in the form of rain showers
and wind from this system, especially if this system develops
further to the west than currently modeled. For now, have no
more than chance pops in the forecast Tuesday and Wednesday to
highlight the uncertainty. High pressure builds back across the
region for the end of next week. Below normal temperatures to
start the forecast period, but moderating temperatures closer to
normal for Tue-Thu.


Aviation /13z Friday through Tuesday/...
as of 700 am EST Friday...

A coastal trough is currently situated over southeast Virginia and NE NC.
This will bring light to moderate rain over the region with
highest pcpn chances over southeast Virginia and NE NC during they day. Wind
currently out of the north-northwest will shift to north-northeast and increase
throughout the day from <10kts to 10-20kt gusting to 20-35kt
after 20z with the strongest winds expected at the end of the
taf period and close to the coast. IFR to brief LIFR conditions
likely in orf, phf, and ecg as showers move east. Rain will
taper from west to east while cloud cover of MVFR to IFR
ceilings persists through the taf period.

Low pressure will intensify off the southeast and mid Atlc coast
tonight through Sun night. Potential for strong winds, rain,
and degraded flight conditions expected through sun, especially
at taf locations close to the coast.


as of 405 am EST Friday...

North-northeast winds will be on the increase today, especially across the
southern coastal waters, as low pressure develops off the Georgia/SC
coast. A 1035+mb surface high will quickly dive southeastward
from south central Canada today into early Saturday and over the
northeast states by Saturday afternoon, setting up an
impressive and prolonged pressure gradient across the mid-
Atlantic as a series of low pressure areas deepen and
consolidate off the Carolina coast.

Marine conditions will begin to deteriorate by mid afternoon as the
first area of low pressure lifts slowly northeastward. Winds will
increase to 15-20 kts across the southern coastal waters and the
Currituck Sound. Worsening conditions will spread northward late
this afternoon/early evening as low pressure consolidates off the
Carolinas. An extended period of unsettled to dangerous marine
conditions appears certain from tonight-Sunday night with widespread
gale conditions and likely storm conditions for areas near and south
of Cape Charles including the Currituck Sound. Solid scas will occur
in the rivers, with gale conditions for the lower James River. The
most likely onset of storm/gale conditions looks to be early
Saturday morning. Models have come into better agreement with
respect to the evolution of low pressure and confidence continues to
increase regarding the placement and timing of gale and storm
conditions. After coordination with surrounding offices, have
upgraded to a Storm Warning for ocean zones south of Cape Charles
and the Currituck Sound starting at 06z Sat. Gale warnings are now
in effect for all of the ches Bay and the offshore zones north of
Cape Charles beginning at 05z Saturday. The Gale Warning for the
lower James River begins at 11z. In addition, a High Wind Warning is
now in effect for land areas of coastal southeast Virginia (norfolk and Virginia beach)
and for Currituck, Pasquotank and Camden counties in NC through
late Saturday.

Seas are forecast to build to 12-19 ft offshore with waves in the
ches Bay up to 5-7 ft (perhaps up to 8-9 ft at the mouth). A high
surf advisory has been issued from Virginia Beach on south and will
need to be extended north to Ocean City later today. Winds are
expected to diminish to below gale criteria late Sun night-
early Mon am, before falling below Small Craft Advisory criteria during the late
Mon- Mon night timeframe. However, seas likely remain elevated
through early next week. Will end the gale/storm warnings at 23z


Tides/coastal flooding...
as of 630 am EST Friday...

A prolonged coastal flood event will unfold this weekend, with
the worst conditions expected to occur Sunday. Strong low
pressure will develop off the southeast coast this weekend
leading to a prolonged period of strong onshore north-NE flow
Saturday through Sunday night. This will allow tide departures
to rise through the weekend, leading to many areas along the
Atlantic coast along/south of Chincoteague, and lower Chesapeake
Bay to see moderate coastal flooding (with departures of 2-3 ft
above normal tide) by the Sunday morning high tide cycle. In
fact, some spots (such as Jamestown and areas along the NE NC
coast) could reach major coastal flooding on Sunday. In
addition, many spots may even see some minor-moderate coastal
flooding with the Saturday afternoon/evening high tide cycle
given that we will already have widespread gale force winds over
the waters by that point. With the potential for a long
duration coastal flood event, combined with the potential for
significant beach/dune erosion from the breaking waves, have
opted to issue a coastal Flood Watch for the Atlantic coast
south of Chincoteague, as well as the lower Chesapeake Bay and
up the James/York rivers. Am currently expecting inundation of 2
feet or greater in places normally susceptible to coastal
flooding, especially on Sunday due to the higher astronomical
tide. Given how quickly seas will build and winds increase
across the south as early as Saturday morning's high tide cycle,
went ahead and upgraded to a coastal Flood Warning from
Northampton County, Virginia to Virginia Beach and Currituck County where
moderate flood thresholds should be reached quickly.


Akq watches/warnings/advisories...
Maryland...Wind Advisory from 7 am Saturday to 6 PM EST Sunday for mdz025.
NC...High Wind Warning from 4 am Saturday to 6 PM EST Sunday for
Wind Advisory from 4 am Saturday to 6 PM EST Sunday for ncz032.
Coastal Flood Warning from 7 am Saturday to 3 am EST Monday
for ncz102.
High surf advisory from 4 am Saturday to 6 am EST Monday for
Virginia...coastal Flood Watch from Saturday morning through late Sunday
night for vaz084-086-089-090-093-095>097-099-523>525.
High Wind Warning from 4 am Saturday to 6 PM EST Sunday for
Wind Advisory from 4 am Saturday to 6 PM EST Sunday for vaz097-
Coastal Flood Warning from 7 am Saturday to 3 am EST Monday
for vaz098-100.
High surf advisory from 4 am Saturday to 6 am EST Monday for
Wind Advisory from 7 am Saturday to 6 PM EST Sunday for vaz099-
Marine...Gale Warning from midnight tonight to 6 PM EST Sunday for
Storm Warning from 1 am Saturday to 6 PM EST Sunday for anz633-
Small Craft Advisory from 7 PM this evening to 6 PM EST Sunday
for anz635>637.
Gale Warning from 6 am Saturday to 6 PM EST Sunday for anz638.


near term...lkb
short term...cmf/lkb

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