Area Forecast Discussion
Issued by NWS Wakefield, VA
FXUS61 KAKQ 191749
Area Forecast Discussion
National Weather Service Wakefield VA
1249 PM EST Thu Jan 19 2017
High pressure will build over the Mid Atlantic today. The high
slides off the coast tonight as a front moves in by Friday. A
complex low pressure system will affect the region early next
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Latest sfc analysis shows 1021 mb high pressure centered over
OH/WV with a stalled frontal boundary across the SE states.
Aloft, a mid-level ridge is located over the eastern CONUS. The
sfc high will build east today and become centered over the Mid
Atlc by this aftn as the ridge axis aloft also moves towards
the area. This will allow for a dry weather day with light
winds and partly/mostly sunny skies. Temps will be about 10
degrees above normal...highs in the mid/upr 50s most areas
except lwr 50s near the coast.
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
The high moves offshore this evening as moisture approaches
from the west after midnight. Latest suite of models keep the fa
dry through 09-12Z with light rain developing mainly west of
I95 by 12-15Z. Pcpn remains liquid with lows upr 30s to near 40.
Friday progged rather wet as a decent overrunning event setting up
ahead of an approaching warm front. Likely pops spread across the fa
throughout the day except categorical pops NWRN zones during the
late morning. QPF one quarter inch or less. Highs in the mid
50s most areas.
Best forcing pushes offshore Friday evening as low pressure moves
east and out into the VA capes with weak high pressure building
into the area. Evening pops will be confined to areas east of
I95 with skies remaining mostly cloudy after midnight. Could
see patchy fog/drizzle develop with lows 40-45.
Latest data supports the weak high moving offshore Sat morning with
moisture from the south quickly advancing NE across the Mid Atlantic
region Sat afternoon. Thus, will carry chc pops mainly south of I64
after 18Z. Highs Sat in the upr 50s to lwr 60s.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A period of warm and wet weather is expected during at least the
first half of the extended period. Upper level ridge axis lifts
northeast of the region Saturday night and Sunday ahead of a
shortwave lifting from the Deep South into the Mid-Atlantic.
Meanwhile, a potent upper low tracks across the Southern Plains into
the Gulf States Sunday. Deep layer southwesterly flow will advect
anomalous precipitable water values into the region ahead of the
approaching lead shortwave energy. Strong isentropic lift will
result in widespread precipitation overspreading the region Saturday
night into Sunday. Have retained likely POPs across the forecast
area Sunday. Cannot rule out some convection across the southern
local area Sunday, nearest the lifting warm frontal boundary. Highs
Sunday in the mid to upper 50`s north to low 60`s south. The upper
low ejects northeast into the Mid-Atlantic Sunday night as an
associated area of low pressure lifts over the Carolinas. Likely
POPs continue Sunday night thanks to anomalous moisture and
impressive forcing for ascent. Lows in the mid to upper 40`s north
to mid 50`s south. There remains some spatial differences with
respect to the surface low placement and potential dry slotting into
Monday, but will continue with high end chance to likely POPs as the
upper low parks over the region. Highs in the upper 50`s to low
60`s. The upper and surface lows lift northeast of the region
Tuesday, with drying conditions southwest to northeast. Highs
Tuesday in the mid to upper 50`s. Upper/surface high pressure
expected Wednesday ahead of the next approaching storm system. Highs
generally in the upper 50`s to low 60`s.
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Sfc high pressure over the area will continue the VFR conditions
through most of the 18Z forecast period. Expect the 3K FT BKN SC
deck at SBY to dissipate by sunset. BKN CI will lower into a BKN
AC deck by 12Z. Models don`t spread any pcpn east until after 14Z.
Thus, only TAF site with pcpn will be RIC with MVFR cigs/vsbys in
light rain/fog expected before 18Z.
Outlook: IFR/MVFR conditions expected Friday afternoon as rain
overspreads the etire area. The steady rain ends but expect
areas of drizzle / fog Friday night into early Sat. Adverse
aviation conditions expected into early next week as series of
disturbances are expected to track across the area.
Sfc high pressure builds over the waters today through late tonight
with light and variable winds anticipated Thu aftn through Fri
morning. Seas 2-3ft today...building to 2-4ft due to nly swell from
a sfc low well off the Mid Atlantic coast. Waves 1-2ft. Sfc high
gets pushed offshore late tonight as an upper low over the Plains
today rotates up into the Midwest through Fri. Winds become se-s
aob 10kt on Fri. A weak coastal trough is anticipated to develop
Fri aftn/evening along a warm front that lifts nwd to roughly the
VA/NC border and essentially stalls there through Sun. Winds become
more n-ne by Sat morning...turning more e-se Sat aftn/night with
speeds remaining no higher than 10kt during this time. The 2-4ft
seas will persist into Fri and then subside to 2-3ft Fri night into
Sat as the warm front moves over the srn waters. Waves continue at
1-2ft during the same timeframe.
Meanwhile, a more vigorous low pressure system exits the Four
Corners Region and swings across TX/OK and the Lower Mississippi
Valley on Sun...pushing across the Southeast States Sun night and
into the Mid Atlantic Region on Mon along the stalled warm front.
The pressure gradient tightens in response to the incoming sfc low
and winds become more onshore/e-se Sun through Mon. Speeds
anticipated to increase to 10-15kt by Sun aftn and then increase to
15-20kt late Sun night into Mon as the sfc low nears the coast. Model
guidance is not picking up on stronger wind speeds just yet, however
stronger sustained speeds and the potential for gale gusts will be
possible. Seas 3-4ft Sun are expected to build to 5-6ft late in the
day through Sun night...locally higher to 6-9ft north of Parramore
Island. Waves building to 2-3ft (possibly up to 3-4ft srn Bay) within
the same timeframe. Seas build more uniformly on Mon with the sfc low
passing over the waters with wave heights of 4-6ft south/6-10ft north.
Waves 3-4ft srn Bay/2-3ft nrn Bay.