Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 250737
Area Forecast Discussion
National Weather Service WAKEFIELD VA
337 AM EDT Sat Mar 25 2017
High pressure remains offshore the Mid-Atlantic coast through
Monday. An upper level disturbance lifts over the region
Sunday. A cold front crosses the region Tuesday night.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Sfc hi pres has become established off the SE CONUS coast and
will remain so today. Deep layered SW flow in place...and will
result in continued warming. Starting out in the 50s to around
60F...and despite periods of high level clouds...temperatures
expected to rise well into the 70s to around 80F...w/ exception
to right near the coast/on the eastern shore where highs will be
in the u60s-m70s. Dewpoints noticeable higher today than
Fri...mainly will average from the u40s-l50s...and SW winds will
be gusty to 20-25 mph in the early-mid afternoon.
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Remaining dry/mild tonight ahead of low pres lifting ENE from
the mid MS Valley into the wrn OH Valley. A weak sfc boundary
will settle over the ern shore by late tonight resulting in
light onshore winds and possible BKN ST. Otherwise...S winds
will prevail under mainly BKN-OVC CI. Lows m-u40s on the ern
shore to the l-m50s elsewhere.
Weakening low pres (sfc-aloft) will continue to track NE the
Great Lakes Sun-Sun night...pushing a weak low level boundary
into/across the FA. Only SLGT forcing aloft w/ this
system...which will likely limit pcpn coverage. Otherwise...VRB
clouds and mild w/ PoPs mainly confined to I 95 on W (20-30%) by
late Sun afternoon/Sun night. Highs Sun from the l-m60s along
the coast/on the ern shore to the l-m70s inland (in VA/NE NC).
Lows Sun night in the u40s- around 50F on the ern shore to the
Initial system lifts into/through New England Mon...leaving FA
w/ continued mild/warm conditions as hi pres (sfc-aloft) remains
invof SE CONUS coast. VRB clouds Mon w/ PoPs mainly aob 20%.
Highs mainly in the 60s on the ern shore to the l-m70s
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Medium range period will remain mild, courtesy of warm southerly
flow from lingering high pressure just offshore of the mid-atlantic
coast. Other main weather feature of note will be a rather
progressive mid-level shortwave traversing the western/central CONUS
late Sat-Monday, before lifting E-NE across the mid-South toward the
local area on Tuesday. High end chance POP remains in place for
showers and sct T-Storms. While the system will be weakening, given
decent instability and favorable diurnal timing, will continue
thunder wording for all but far NE zones (later timing). Shortwave
ridging behind the wave will bring slightly cooler, albeit still
mild, and drying wx Wed and Thu. Forecast highs mainly in the 60s to
near 70 far north and along the immediate coast...70s to near 80
west of the Bay on Tuesday, 60s to mid 70s on Wednesday...with temps
trending back to around climo normal for the latter half of next
week. Next chance of rain comes by the end of the period late next
week in association with another weakening southern stream upper low
traversing the southern tier of the country. For now, rain chances
are re-introduced by late on Thu/Fri.
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions through the 06Z TAF period. SSW winds average
10-15 kt...gusty to 20-25 kt early/mid this afternoon and
With weak sfc boundary pushing S to near SBY tonight...low prob
for IFR (in ST and/or patchy fog). Otherwise...ISOLD-SCT SHRAS
possible by late Sun into Mon...w/ only brief periods of reduced
aviation conditions possible during times of precipitation.
High pressure is well offshore with a weak wedge left in the lee
of the Appalachians. This feature should delay the onset of rain
until mid to late morning as a cold front continues to advance
on the area...effectively outrunning (or getting ahead of) the
precipitation by late morning/early aftn. Weak troughing along
the coast will cause the pressure gradient to tighten invof the
cold front. Meanwhile, weak warm air advection will act to hamper
the development of stronger winds. Overall, winds become s-sw
10-15kt (up to 20kt nrn coastal waters) by early aftn; peaking
during the cold frontal passage. Seas build to 2-4ft; waves to
2ft. Little change to the airmass tonight behind the front as
warmer air stays in place with strengthening high pressure
building well north of the waters through Sun night. N winds
tonight through Sun aob 15kt...becoming ne-e and diminishing to
aob 10kt Sun night. Seas average 2-3ft; waves average 1-2ft.
Main high pressure slides over Nrn New England/Canadian Maritimes
on Mon. E-se aob 10kt. Weak wedging remains in place in the lee
of the mts as a very strong low pressure system tracks into the
Upper Great Lakes Mon and across Ontario/Quebec Mon night. The
pressure gradient tightens up late Mon night into Tue aftn ahead
of the front and s winds will increase to 15kt Bay and 15-20kt
all coastal waters. Seas generally build to 3-4ft in this
timeframe (up to 5ft possible coastal waters north of Parramore
Island). Waves generally 2ft; occasionally up to 3ft. SCA flags
are not anticipated.