Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 161534
Area Forecast Discussion
National Weather Service Wakefield VA
1034 AM EST Thu Feb 16 2017
High pressure builds along the Gulf coast today into Friday, as
strong low pressure off the New England coast moves north to
the Canadian maritimes. This area of high pressure then slides
offshore of the southeast coast Friday into Saturday. A weak
area of low pressure moves through the Carolinas Saturday night
with high pressure returning by Sunday afternoon.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --Current analysis indicating intense sfc low pressure centered
near Halifax, NS (~968 mb), with ~1022 mb sfc high pressure
centered over the western Gulf of Mexico. A cold upper trough is
in place over NY/New England. The sky is mostly sunny across the
srn half of the area this morning, with sct-bkn mid clouds over
the Ern Shore, and a bkn-ovc deck ~7kft from nrn to e-central
VA. For today, shortwave energy will continue to round the base
of the upper trough, with 500mb heights of -2 std dev and 850
mb temperatures to -6C SW to -10C NE, which should yield highs
only in the low-mid 40s over the N and upper 40s across the S
even in a well mixed BL. Sky cover should average partly sunny
to occasionally mostly cloudy NE to mostly sunny SW as a strong
channeled vort max continues to pass over the area. A NW wind
of 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 (gusts mainly 25-30 mph elsewhere). Very dry/low dew pts
this aftn, but with yesterday`s rainfall and fairly cold
temperatures, Fire wx concerns should be minimal.
The main upper trough will push offshore tonight into Friday
morning, with a shortwave trough dropping sewd across the
region, within NW flow aloft late tonight 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 tonight are expected to range from
the mid 20s to around 30 F.
-- End Changed Discussion --
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Partly-mostly cloudy skies Friday morning become mostly sunny by
midday and with low level flow shifting to the SW, highs
moderate into the 55-60 F most areas W of the Bay, except 50-55
F over the NE (and upper 40s/around 50 F 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 60s to around 70 F (50s
at the immediate Atlantic coast of the Ern Shore), after
morning lows in the 30s. Clouds potentially increase Saturday
aftn, mainly SW, as a srn stream system pushes into the Tennessee
Valley. This system will be weak, but should see skies turn
mostly cloudy Sat night with milder lows in the 40s to near 50
F. Models showing split in precip pattern with some light
precip moving well N of the low into central VA, and another
area of precip genly staying S/SE of the CWA. Will continue with
mainly just a 20-30% PoP Sat night, with QPF amounts to be
light/less than 0.10".
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A weak coastal low/trough and an upper level trough will primarily
pass south of the region Sun morning. There may be enough
isentropic lift present for light rain showers across the srn
half of the CWA during this timeframe. 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 /16Z THURSDAY THROUGH MONDAY/...
High confidence that VFR conditions will prevail through the 12Z
TAF period. Gusty WNW winds will pick back up over the next few
hrs sustained northwest winds of 12-15 knots and gusts of 20-25
KT, mainly from 14Z-22Z. Skies to avg FEW-SCT southwest to SCT-
BKN northeast but any Cigs would be 5,000 ft or higher. Lighter
winds tonight, with increasing mid/high clouds after midnight.
Outlook: VFR conditions are expected Fri/Sat. Low pressure
tracks off the Southeast coast Saturday night and into Sunday
bringing a chance for spotty light rain but overall conditions
should be mainly VFR. High pressure returns later on Sunday and
into early next week.
Latest surface analysis depicts deepening low pressure offshore of
the Northeast coast with high pressure over the Southern Plains. The
result is a northwest wind over the local waters. A brief lull in
speeds is observed over the local waters early this morning ahead of
a secondary front/cold surge. This front pushes offshore by daybreak
as the Northeast low deepens. Northwest winds increase back to 20-25
knots with gusts to 30 knots early this morning. 15-20 knots with
gusts to 25 knots in the rivers. Waves 2-4 feet and seas 4-6 feet.
Surface low continues to deepen and lift over the Canadian Maritimes
today as high pressure builds over the lower Mississippi River
Valley. The result will be ongoing cold air advection and SCA
conditions. Gust in the Bay become 25 knots this afternoon, but
remain 30 knots over the coastal waters. Waves remain 2-4 feet and
seas 4-6 feet. A high pressure ridge builds in from the west late
today and tonight as cold air advection wanes, resulting in
improving conditions through this evening. Expect sub-SCA conditions
to return to all waters by midnight. Waves diminish to 2-3 feet and
seas 3-4 feet.
Sub-SCA conditions persist through Saturday with varying degrees of
southwest to west flow. Speeds generally at or below 15 knots. Waves
1-2 feet and seas 2-3 feet. A front pushes across the waters
Saturday night as low pressure develops along the southeast coast.
Flow becomes northwest Sunday, but sub-SCA conditions prevail. High
pressure returns early next week.
MARINE...Small Craft Advisory until 4 PM EST this afternoon for
Small Craft Advisory until 1 AM EST Friday for ANZ630>632-634-
Small Craft Advisory until 7 PM EST this evening for ANZ633.
Small Craft Advisory until 10 PM EST this evening for ANZ654-