Area Forecast Discussion
Issued by NWS Wakefield, VA
FXUS61 KAKQ 110030
Area Forecast Discussion
National Weather Service Wakefield VA
730 PM EST Sat Dec 10 2016
Canadian high pressure remains over the Mid-Atlantic tonight, before
sliding offshore Sunday. A warm front will lift through the region
Sunday night as low pressure moves into the Great Lakes. This area
of low pressure will push north of the area Monday, with the
associated cold front crossing the region late Monday.
Another strong cold front impacts the region during the middle of
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Latest wx analysis features Cold sfc high pressure (1034mb)
in place over the area this evening, under fast, quasi-zonal
flow aloft. Light winds and a clear sky under the sfc high have
allowed temperatures to plummet as expected early this evening,
with temperatures already in the mid- upper 20/low 30s at 00z.
Expect increasing mid to high clouds (highest concentration N) to
hasten the drop off in temperatures late in the overnight. The
clouds are in association w/ a nrn stream trough that is diving
across the Great Lakes region tonight. Temp curve will look a
little different tonight (temps dropping off faster, stabilizing
late) but early morning low temps will be similar to those of last
night: mid to upper teens rural areas, upper teens to low 20s
elsewhere...w/mid 20s to near 30 along the immediate coast.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Aforementioned shortwave trough pushes north of the region through
the day, shearing apart as a more potent wave dives into the
upper Midwest and a mid-level ridge axis remains over the Mid-
Atlantic. The surface high slides offshore, but warming in s-se
flow will be tempered by limited mixing. Sunday morning should be
partly cloudy south to mostly cloudy north, with decreasing clouds
possible during the aftn. Forecast highs will still be below
normal and moderate only into the low/mid 40s to near 50 se.
The vigorous nrn stream wave dives through the Great Lakes Sunday
night with the mid-level ridge axis pushing offshore. This will
allow for a warm front to lift through the Mid-Atlantic. Clouds
quickly thicken and lower, with PoPs increasing for light rain from
s-central VA to the coast during the late evening and early
overnight hours as a coastal trough pushes newd ahead of the
approaching system and interacts with the warm front. Lows Sunday
night will likely occur during the evening hours, ranging from the
mid 30s nw to the low 40s se. Becoming damp and chilly from the
interior coastal plain to the Piedmont as the cool air will be
stubborn to erode, with temperatures potentially rising to the
low/mid 50s along the immediate coast by 12z Monday. No frozen pcpn
is expected at this time across the far nw Piedmont counties as
temperatures are expected to remain above 32F and remain steady or
slowly rise once any pcpn arrives.
A srn stream wave tracks across the region through midday Monday, as
the nrn stream wave moves toward the Saint Lawrence Valley by aftn,
which will push the associated cold front into the area.
Forecast PoPs are highest (60-70%) from morning through mid-aftn.
Deep-layered w-sw flow will limit QPF, which at this time is
forecast to be aob 0.3". Milder but temperatures will still
struggle to rise above the upper 40s over the nw Piedmont, with
mid 50s to around 60 se.
The cold front pushes s of the region Monday night and stalls across
the Carolinas. Lingering rain ends early Monday evening, with the
sky becoming partly cloudy north. Lows range from the mid 30s n/nw
to the mid 40s se. Another wave tracks along the front Tuesday,
which could bring some rain to ne NC. Otherwise partly sunny north
to mostly cloudy south with highs ranging from the upper 40s north
to mid 50s south.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Sfc high pressure slides offshore Tue evening as another coastal
trough develops along the Southeast Coast. Broad upper level
troughing across nrn Ontario into the Great Lakes Region should
keep the coastal system/persistent troughing generally suppressed
along/south of the VA/NC border Tue night through Wed with winds
remaining north around 10kt or less. By Wed night, the upper
trough digs through the Mid Atlantic Region...pushing the coastal
trough out to sea and bringing another arctic blast to the area.
Winds shift to the northwest and increase to 15-20 mph along the
immediate coast Wed night into Thu with the surge of colder air.
Canadian high pressure builds into the region Thu/Fri.
Overall, temps will be at to slightly below normal Tue night/Wed...
becoming much colder Wed night through Fri (-1 Std Dev) with highs
in the mid 30s nw to lower 40s se. Lows Wed night in the lower
20 nw to lower 30s se and Thu night in the upper teens nw to mid
20s far se.
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
High pressure and fair weather will remain in control through
this TAF period allowing for VFR conditions to continue. A few
higher clouds may begin to filter into northern portions of the area
this afternoon and into tonight, bases should remain at or above
10Kft. Winds will generally remain light (5-10 knots) and out of the
W-NW this afternoon. Winds will remain light, but will begin to
shift towards an easterly direction as we head into tomorrow.
Outlook: High pressure begins to slide offshore on Sunday. There
will be a chance for rain Monday as a cold front approaches from the
west. Another cold front approaches the area on Wednesday, bringing
a chance of rain to the area.
Sfc high pressure continues to build into the area this evening
and slides over the waters late tonight into Sun morning. Winds
generally w aob 10kt (15kt coastal waters north of Parramore
Island through this evening). Winds become more se aob 15kt as
the sfc high slides offshore and a warm front lifts north through
the area during the day. Meanwhile, a low pressure system tracks
across the Great Lakes Region Sun night as a very weak coastal
trough develops along the Southeast Coast. The weak trough will
get pulled up twd Cape Hatteras Sun night ahead of a cold front
associated with the Great Lakes low. This feature should bring
rain up along the Mid Atlantic coast after midnight Sun night
into Mon morning with a period of dry conditions possible over
the waters the rest of the day on Mon as they reside well within
the warm sector ahead of the cold front. Sw winds on Mon will
experience a brief surge in the morning with speeds just below
SCA criteria (aob 15kt Bay/Sound/Rivers...aob 25kt coastal
waters). Seas average 1-2ft tonight-Sun...building to 3-4ft Sun
night. Waves 1-2ft...building to 2-3ft late Sun night.
The cold front crosses the waters Mon evening with scattered
showers tapering off quickly as they get sheared apart. Seas may
reach 5ft out near 20 nm (north of Parramore Island) just ahead
of the frontal passage but should be short-lived. The airmass
behind the front is modified/not much cooler and n winds are
expected to remain aob 15kt all waters late Mon night. Weak sfc
high pressure moves quickly into the region on Tue...resulting
in light n winds aob 10kt Tue. The high slides offshore by Tue
evening as another coastal trough develops along the Southeast
Coast. Broad upper level troughing across nrn Ontario into the
Great Lakes Region should keep the coastal system/persistent
troughing generally suppressed along/south of the VA/NC border
Tue night through Wed with winds remaining n aob 10kt. Seas
2-3ft/waves 1-2ft. By Wed night, the upper trough digs through
the Mid Atlantic Region...pushing the coastal trough out to sea
and bringing another arctic blast to the area. Winds shift to
the nw and increase to 15-20kt (gusts 25-30kt over coastal
waters) Wed night into Thu with the surge of colder air. Seas
build to 3-5ft/waves build to 3ft Wed night into Thu.