Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 151455

Area Forecast Discussion
National Weather Service Wakefield VA
955 AM EST Fri Dec 15 2017

High pressure retreats to a position off the New England coast
today. Meanwhile, low pressure develops just off the coast this
afternoon, then tracks northeast and away from the area
tonight. High pressure returns for the weekend.


1020mb high pressure is centered over Long Island this morning
and is ridging to the SW across the VA Piedmont and 1014mb low
pressure is located ESE of Cape Hatteras. Cloudy this morning
with temperatures ranging from the low 30s N to the low 40s SE.

Sfc high pressure will get squeezed to the NE today as low
pressure and an upper trough pivot through the Great Lakes.
Meanwhile, the wave low pressure off the Outer Banks is expected
to quickly track NE off the mid-Atlantic coast late this
afternoon and evening. Latest guidance brings a swath of
moisture across the northern tier of the FA around midday, then
over the Eastern Shore this afternoon and early evening before
exiting the coast by 10 pm. Some enhancement of the moisture is
noted by the latest hi-res guidance with support from the 00Z
suite of models this aftn/eve as it crosses the Eastern shore,
particularly across northern Dorchester County. Bufkit soundings
suggest about a 3-5 hour period of pcpn between 18Z-00Z with
pcpn possibly lingering near OXB thru about 02Z Sat. Have slight
chc PoPs (~20%) north of RIC late this morning/midday, then
increasing to likely/categorical (55-80%) over the MD Eastern
Shore this afternoon. Otherwise, dry south of I-64.

Thermal profiles suggest mainly snow across Dorchester County,
with a buffer area of a rain/snow mix to snow across Caroline
County, the Northern Neck, and the rest of the interior lower
MD Eastern Shore. Most likely it`s just plain rain along the MD
coast, mixing with or changing to snow briefly before ending.
Sfc temps will primarily remain above freezing during the event,
limiting snow accumulations before falling by sunset. For that
reason, kept snow accumulations limited to the lower MD Eastern
Shore. Generally under one-half inch expected, but with highest
amounts up to ~1" possible across northern Dorchester County. In
coordination with neighboring offices, will not be issuing a
Winter Wx Advisory at this time due to minimal snow
accumulations and temps AOA freezing. However, timing of the
heaviest snowfall will occur around the late aftn/eve commute so
motorists should be prepared to take necessary precautions.
Highs today mid-upr 30s north to low mid 50s NE NC.


Any lingering snow shower push of the MD coast by late eve with
decreasing from west to east. Lows mid 20s NW to lwr 30s SE.

High pressure builds over the sern states Sat then moves offshore
Sun. Dry through this period. Highs Sat in the mid-upr 40s.
Lows Sat night mid 20s NW-mid 30s SE. Highs Sun upr 40s N to
mid 50s S.


A welcomed return to south-southwesterly flow on Sunday will bump
temperatures into the middle 50s. High pressure slowly meanders
offshore to the east on Sunday night and into Monday, allowing for
an uptick in moisture advection across the south.

The European is beginning to lean towards a drier, GFS-like solution
for Monday. Better chances for measurable rainfall exist across our
NC counties and extreme southeastern VA Monday aft/eve. Temperatures
during the day will rise into the upper 50s, so no worries about any
wintry precip.

Tuesday`s temps will strive for the low 60s in the afternoon, with
one caveat being cloud cover. The GFS and EURO begin to disagree
during this timeframe, with the EURO being much drier at the mid
levels than the GFS. As such, the GFS is more bullish on cloud cover
and rain chances Tuesday afternoon and evening. Leaned more towards
the EURO solution, trimming back PoPs Tuesday...will wait for better
model agreement to increase confidence on Tuesday being any drier
than currently forecast.

The spigot abruptly shuts off early Wednesday morning as any
moisture slides off the coast. Expect highs Wednesday and Thursday
to be 7-10 degrees cooler than Tuesday.


High pressure heads NE today and a coastal low pressure system
passes offshore of the region this afternoon/evening.
Precipitation is expected to develop mainly after 18Z and impact
primarily SBY/Eastern Shore. The precipitation will be a rain/snow
mix at SBY, bringing the potential for MVFR TO IFR CIGS/VSBYS
between 18Z and 00Z. MVFR CIGS will also be possible between 18Z
and 00Z at ORF and PHF.

Outlook: The coastal low pressure system moves well offshore
tonight and high pressure builds back into the area for the
weekend. VFR conditions are expected through the weekend before
a weak disturbance potentially impacts the region on Monday.


Sfc high pressure over MD/DE will retreat NE later today as sfc low
pressure just off the Carolina coast slowly tracks NE off the NC/VA
coast this aftn and intensifies this evening while moving farther NE
off the mid-Atlc coast. While this system is not particularly strong
and the rapid intensification looks to be delayed until it moves
farther out to sea, think at least marginal SCA conditions are
likely to be met this evening into early Sat morning. Raised SCA
headlines for all coastal waters/Bay/Currituck sound mainly for
tonight, though expect the higher winds to linger into late Sat
morning for northern coastal waters where pressure rises in excess
of 1mb/hr persist a few hrs longer.

Winds will diminish to 10-15 kt by Sat aftn as as sfc high
pressure becomes centered over the SE US coast, winds will shift
more to the SW from Sat night through Sunday with speeds
averaging around 10 kt. Winds will remain light on Monday, but
expect a strong increase on Tuesday as a frontal boundary and
developing surface low approach the area, followed by another
shot of cold air for the midweek time frame.


MARINE...Small Craft Advisory from 7 PM this evening to 7 AM EST
     Saturday for ANZ630>632-634-656-658.
     Small Craft Advisory from 7 PM this evening to 4 AM EST
     Saturday for ANZ633.
     Small Craft Advisory from 10 PM this evening to 10 AM EST
     Saturday for ANZ650-652-654.


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