Area Forecast Discussion
Issued by NWS Wakefield, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 152336
Area Forecast Discussion
National Weather Service Wakefield VA
636 PM EST Wed Feb 15 2017
A cold front pushes through the region this evening. High pressure
builds in from the northwest later tonight into Thursday. This area
of high pressure then slides offshore Friday into Saturday.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Current GOES wv imagery shows a shortwave trough pushing
off the Mid-Atlantic coast, with a secondary wave dropping sewd
across wrn PA and WV. The main band of rain has pushed offshore,
with some lingering showers associated with the nrn stream system
pushing across E-central VA, the Ern Shore, and SE VA through late
aftn. Temperatures this aftn range from the low/mid 50s inland where
low clouds have given way to sct cu, with upper 40s closer to the
coast where thicker cloud cover has persisted. At the surface, the
leading edge of the cold front is depicted by falling dewpoints
across the piedmont and central VA, along with a NW wind gusting to
20-25 mph. Colder and drier air steadily moves in from the NW
overnight. Temperatures fall through the 40s this evening, with
overnight lows reaching the mid/upper 20s inland, with low/mid 30s
at the coast. Generally mostly clear overnight to partly cloudy NE
with mid-level PVA embedded within NW flow.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A cold upper trough will pass over the region Thursday,
with 500mb heights of -2 st dev. 850mb temperatures drop to -8 to -
10C, which should yield highs only in the low/mid 40s even in a well
mixed BL. Partly cloudy NE to mostly sunny SW as a strong channeled
vort max continues to pass over nrn portions of the area. A NW wind
of 10-15 mph is expected inland to 15-20 mph closer to and along the
coast, with gusts up to 30-35 mph possible over the Ern Shore.
The main upper trough will push offshore Thursday night into Friday,
with a shortwave trough dropping sewd across the region, within NW
flow aloft late Thursday night into early Friday. This combined with
the commencement of mid-level WAA should produce increasing mid/high
clouds, but dry conditions are expected to prevail. Lows Thursday
night are expected to range from the mid 20s to around 30. Highs
Friday moderate into the low/mid 50s inland with decreasing clouds,
while remaining in the 40s over the Ern Shore.
Mid-level ridging builds front the Ohio Valley Friday night into the
Mid-Atlantic by Saturday. Temperatures will continue to moderate
Saturday with highs rising into the mid/upper 60s (50s at the
immediate Atlantic coast of the Ern Shore), after morning lows in
the 30s. Clouds potentially increase Saturday aftn, mainly S, as a
srn stream system pushes into the Tennessee Valley.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A weak coastal low/trough and an upper level trough will primarily
pass south of the region Sat night into Sun morning. There may be
enough isentropic lift present for light rain showers across the srn
half of the CWA during this timeframe. Expect mostly cloudy skies
with lows Sat night in the mid 40s areawide. Conditions improve
through Sun with clearing skies and high temps in the upper 60s
inland/low-mid 60s closer to the coast (upper 50s to lower 60s
beaches). Otherwise, high pressure returns to the region Sun night
into Mon. Expect mostly clear skies with lows Sun night in the 40s
and highs on Mon in the upper 60s inland/low-mid 60s closer to the
coast (upper 50s to lower 60s beaches). A clipper system is expected
to pass well north of the area late Mon night into Tue night, thus
pushing the sfc high southeast of the local area and flattening the
mid-upper level ridging. Forecast is generally dry with a very
remote chance of showers passing across far nrn counties Tue night
where a weak frontal boundary is expected to be. Lows Mon night in
the 40s under mostly clear to partly cloudy skies. Increasing clouds
Tue/Tue night. Highs Tue in the mid-upper 60s inland to mid 50s-
lower 60s immediate coast. Lows Tue night in the 40s.
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --High confidence that VFR conditions will prevail through the 00Z TAF
period. A cold front will continue to move offshore tonight with
high pressure building into the region for Thursday. Gusty northwest
winds should begin to decrease overnight, expecting winds around 10
knots at all sites overnight. Winds will pick back up after sunrise
on Thursday with sustained northwest winds of 12-15 knots and gusts
in excess of 25 knots at times.
Outlook: VFR conditions are expected through Saturday. Low pressure
tracks off the Southeast coast Saturday night and into Sunday
bringing a chance for showers and potentially sub-VFR ceilings. High
pressure returns later on Sunday and into early next week.
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Two separate fronts will cross the area today. The first pushed
through this morning with moderate to heavy rainfall. Winds are
generally light and variable aob 10kt. Seas generally 3-4ft; waves
1-2ft. The second front is associated with an upper level trough
swinging through the region this evening and will produce persistent
and breezy w-nw winds this evening through Thu, which will gradually
taper off through Thu evening. Strong SCA conditions are anticipated
for all waters starting between 400-500 PM today. Speeds will
average 20-25kt ocean/Ches Bay and 15-20kt Sound/Ern VA Rivers.
Expect wind gusts about 5-7kt stronger than sustained speeds. Seas
quickly build to 4-5ft this evening; waves 3-4ft. These conditions
will be steadily consistent through Thu aftn before wind speeds and
wave heights slowly subside. 12Z model data hasn`t strayed much from
ongoing forecast, therefore don`t see any reasons to change SCA
headlines or wind speed forecast at this time. As mentioned in
previous discussion, a brief period of gale force gusts north of
Parramore Island may be possible late this evening with an
initial cold air push and again Thu morning (after sunrise)
when the pressure gradient tightens up.
The upper low shifts ewd Thu evening as sfc high pressure builds
across the Southeast States. All SCAs will come to an end shortly
after midnight Thu night. Winds nw aob 15kt Bay/Sound/Ern VA Rivers
and 15-20kt ocean overnight Thu into Fri morning. Seas 2-4ft; waves
1-3ft. Otherwise, high pressure will dominate the weather pattern
through at least Sat aftn, after which a weak coastal low and upper
level trough will approach the srn waters and pass primarily south
of the region Sat night into Sun morning. Winds generally sw Fri
through Sat...becoming w Sat night...then w-nw Sun. Speeds aob 15kt
Fri through Sun with seas mainly 2ft and waves 1-2ft. High pressure
returns Sun night into early next week.
-- Changed Discussion --MD...None.
MARINE...Small Craft Advisory until 4 PM EST Thursday for ANZ635>638.
Small Craft Advisory until 10 PM EST Thursday for ANZ630>632-
Small Craft Advisory until 7 PM EST Thursday for ANZ633.
Small Craft Advisory until 1 AM EST Friday for ANZ650-652.
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