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Area forecast discussion 
National Weather Service Wakefield Virginia
925 PM EST Friday Feb 12 2016

Synopsis...
low pressure lifts northeast off the Virginia coast this evening.
Arctic high pressure builds in for the upcoming weekend...resulting
in the coldest temperatures so far this year. Low pressure lifts
from the deep south into the middle Atlantic region early next
week.

&&

Near term /until 6 am Saturday morning/...
forecast updated to cancel the winter storm warng and advisory with
snow ending across southeast Virginia/NE NC. Will issue a Special Weather Statement for black ice
over these areas tonight. -Sn continues over the lower Eastern Shore
tonight...with any accumulations expected to stay below one inch.

Previous discussion...
latest surface analysis centers 1014mb surface low pressure off the NC
coast this afternoon...with high pressure centered just off the
middle- Atlantic coast. Regional radar mosaic depicts area of light
snow moving across east/southeast Virginia...with observation and radar returns
indicating heaviest snow over NE NC. The heaviest band of
snow/sleet and frontogenetic forcing remains along and just south
of the Albemarle Sound. This will continue to be the highlighted
area for the next few hours. Light snow will wind down across eastern
Virginia into southeast Virginia by 5 PM...with little additional accumulation.
Advisories remain in effect with an additional 0.5 inch of
snowfall still possible back into Isle of Wight and Southampton
counties. The surface low deepens and lifts northeastward as the upper level
wave pushes offshore. Snow band will pivot into southeast Virginia late today
before the light snow finally pushes offshore early this evening.
The Arctic boundary then pushes through the region this evening. Have
increased probability of precipitation for the Maryland Eastern Shore to likely late this evening as
shortwave energy along the Arctic boundary will likely result in
additional light snow. Accumulations will generally range from 1
to 2 inches. Northwest winds increase behind the Arctic
boundary...increasing to 10 to 20 miles per hour with gusts 25 to 30 miles per hour
coastal areas and the Eastern Shore. Sky clears SW to NE late
tonight...with overnight lows falling into the teens to low 20s.
Wind chills will drop into the single digits.

&&

Short term /6 am Saturday morning through Monday/...
deep upper trough locates over New England into the Middle-Atlantic
States Sat as the Arctic boundary pushes offshore. Polar front
prognosticated to remain north of the local area. The Arctic high builds
into the Ohio Valley late Sat...ushering in some of the coldest air of
the season. 850 mb temperatures plummet to around -18 to -20c (-2 to -3 Standard
dev). Highs only forecast in the middle/upper 20s inland to low 30s southeast.
Windy...with northwest winds generally 15 to 25 miles per hour with gusts 30 to
35 miles per hour. Gusts over the Eastern Shore and coastal areas expected to
reach 40 miles per hour. While the air mass remains very dry (dewpoints below
0)...Bay streamers and light snow showers are possible over the Eastern
Shore. Will hold onto slight chance probability of precipitation there. Sky averages sunny
southwest to partly cloudy NE. Large scale confluence in wake of the
departing upper low will allow high pressure to build into the
region Sat night. Winds diminish inland...allowing for great
radiational cooling and lows plunging into the single digits to low
teens inland to upper teens near the coast. Wind chill values
generally 0 to 5 above inland and around 5 below Northern Neck to the Eastern
Shore. Will hold off on Wind Chill Advisory at this time.

The Arctic high centers over the middle-Atlantic sun...with highs only
warming into the middle/upper 20s (-2 Standard dev). Sky averages mostly
sunny with a light New York wind. Middle/upper level clouds begin to increase
late Sunday as the next storm system approaches.

The high shifts toward New England Sun night as the next storm
system develops over the deep south Monday. Northern stream energy lifts
north of the region Sun night/Monday as a middle level trough tracks
across the central Continental U.S. Monday. Southwesterly flow aloft will result in
moisture return into the middle-Atlantic region. Probability of precipitation increase late Sun
night as the northern stream system weakens and weak isentropic lift
advects into the region. Air mass will easily be cold enough Sun
night for all snow as lows Sun night will be in the upper teens to
around 20. Precipitation chances increase Monday as a coastal trough sharpens
along the coast and the aforementioned deep south low begins to lift
northeastward toward the local area. Have increase probability of precipitation to likely across the
northwest Monday morning...with likely probability of precipitation across all but southeast Virginia/NE NC Monday
afternoon. Warm air advection aloft/critical thicknesses still indicating a change
over from snow/ice pellets Monday morning to rain closer to the coast Monday afternoon.
Ptype likely to remain all snow northwest. There still remains some timing
and spatial differences in the models...but current snowfall
forecast calls for 1-2 inches along the Interstate 85 corridor into
central Virginia and northern Virginia...with 2-4 inches across the northwest counties.

&&

Long term /Monday night through Friday/...
12/12z numerical models depict low pressure tracking NE from the
deep south to the southern Appalachians Monday evening...then rapidly
deepening as it lifts NE into the middle-Atlantic region by midday
Tuesday as a vigorous upper trough digs across the southern/central
Appalachians. Thermal profiles suggest mixed precipitation could continue
into the evening over the Piedmont. Overnight lows should occur in
the evening...with rising temperatures overnight as the low-level
flow becomes south-southeast. Colder temperatures will likely persist the
longest in the far northwest Piedmont counties where some pockets of -fzra
could continue overnight...but generally all rain is expected by
early Tuesday morning. Periods of moderate rain are possible late
Monday night into Tuesday as a band of strong vertical ascent passes
over the region. Strong pressure falls could produce a modestly
strong southerly wind across the eastern third of the area for a 3-6hr
period Tuesday. Temperatures warm to at least the middle/upper 50s
across the eastern half of the area Tuesday...with low 60s possible
along the coast...while the Piedmont struggles to rise above the
upper 40s/low 50s. Generally expecting drier conditions by Tuesday
night...although some 20-30% probability of precipitation will linger across the north as a
secondary trough swings across the northern mid-Atlantic. Dry and mild
Wednesday under west-northwest flow with highs in the upper 40s to middle 50s. A
cold front tracks across the area Wednesday night...followed by
Canadian high pressure Thursday. This should push temperatures below
normal...but within -1 St dev. A moderating trend commences late
week as high pressure moves offshore and low pressure tracks through
the Great Lakes.

&&

Aviation /02z Saturday through Wednesday/...
low pressure moves off the coast tonight as Arctic high builds into
the Middle Atlantic States during the weekend. The high moves off the
coast as low pressure moves northeast from the Gulf Coast states
early next week.

As of 01z...snow has ended over southeast Virginia/NE NC but continues over
portions of the lower Eastern Shore. As the leading edge of Arctic
air approaches and moves through...there may be more snow at sby.
Have light snow in the taf for most of the overnight. This could go
to IFR but not expected to last for very long.

MVFR ceilings are expected for the next few hours southeast portions with some
IFR indicated at ecg. Conditions slowly improve through the early
morning with a mostly clear sky indicated for Saturday. The
exception would be at sby where stratocu is expected to produce a
ceiling of around 5k feet through much of the day Saturday.

Outlook...dry and VFR conditions are expected through Sunday night.
There will be a chance for snow across the area Monday morning turning
to rain from southeast to northwest Monday afternoon. Widespread rain is indicated
Monday night and Tuesday. Periods of IFR are expected with the
precipitation. Dry and VFR weather return for Wednesday.

&&

Marine...
low pressure is tracking east-northeast off the NC coast this
afternoon. Meanwhile...another area of low pressure is tracking
across the eastern lakes...with an Arctic cold front trailing through
the Ohio Valley...and Arctic high pressure spilling into the upper
Midwest. The coastal low will bring a period of snow...which will
reduce visibility late this afternoon and evening (mainly s). As the low
lifts to the NE tonight the Arctic cold front will pass across the
region with strong cold air advection developing late tonight...and continuing
through Saturday into Saturday night as the Arctic high builds in
from the northwest. A northwest wind will average 25-30kt with frequent gusts of
35-40kt over the ocean and Bay. Seas build to 5-8ft with 4-5 feet
waves in the Bay. Gale flags continue for late tonight through
Saturday night. For the rivers and sound...wind speeds remain capped
at high-end Small Craft Advisory at this time. Freezing spray is expected as
temperatures plummet Saturday and especially Saturday night/Sunday
morning...with a freezing spray advisory in effect for Saturday
night into Sunday morning. The wind will diminish Sunday into Sunday
night as the high settles across the area. Low pressure approaches
form the SW early next week...and tracks up the Piedmont Tuesday.
This will allow for a modestly strong south-southeast wind and building
seas/waves.

&&

Tides/coastal flooding...
strong northwest flow associated with an Arctic cold front will produce
blow-out tides / low water advisories for some areas early
Saturday morning...and much of the coastlines Saturday afternoon
and night. The main areas early Saturday morning that could have
low water are along the atlanitc coast north of Cape Charles. A low
water advisory has been issued from 08-13z (3 to 8 am).

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory from 4 am Saturday to 10 am EST Sunday
for anz633-635>638.
Freezing spray advisory from 7 am Saturday to noon EST Sunday
for anz630>632-634-650-652-654-656.
Gale Warning from 4 am Saturday to 4 am EST Sunday for
anz630>632-634-650-652-654-656-658.
Low water advisory from 3 am to 8 am EST Saturday for anz650-
652-654.
Freezing spray advisory from 7 PM Saturday to noon EST Sunday
for anz658.

&&

$$
Synopsis...Sam
near term...mas/Sam
short term...Sam
long term...ajz
aviation...lsa
marine...ajz
tides/coastal flooding...

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