Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 291837
Area Forecast Discussion
National Weather Service Wakefield VA
237 PM EDT Thu Sep 29 2016
An upper level low slowly drops south from the Great
Lakes overnight through Friday. Meanwhile, high pressure builds
well north of the region and steers a moisture rich airmass into
the region tonight Through Thursday night.
.NEAR TERM /THROUGH TONIGHT/...
Current GOES water vapor imagery depicts the center of an
anomalous upper low near the IN/KY border. Upstream of the upper
low, a plume of anomalous moisture extends from the coasts of
NC/se VA to the Delmarva and into Ern PA/NJ. Blended TPW imagery
shows pw values of 1.5-2.0", which is around 150-200% of normal.
At the surface, low pressure is centered over wrn NC with a
trough off the NC coast. 1039mb high pressure is centered over se
QB and is ridging sw through New England and into the nrn Mid-
Atlantic. Visible imagery depicts cloud cover over most of the
area. However, there are some breaks across se VA/ne NC. A vast
majority of the area is experiencing a break in rainfall, with
shra concentrated along the wrn shore of the Bay, the Atlantic
coast around Ocean City, with iso-sct coverage over interior ne
The upper low continues to dig southward through the Ohio Valleys
today into tonight. Meanwhile, upper ridging builds north of the
Great Lakes across southeast Canada. This will focus increasing
moisture flux and enhanced convergence north of the frontal
boundary draped across central Virginia. However, a high
precipitable water airmass (1.5-2.0") remains over the local area
today, resulting in a continued heavy rainfall threat across the
northern half of the area into tonight. Afternoon convection will
enhance the rain rates. Rainfall amounts could reach 2-3 inches
across the far northern tier counties bordered by 1-2 inches from
Emporia to the Maryland Eastern Shore. A flash flood watch
remains in effect through tonight.
Highs today generally in the mid 70`s inland to low 80`s
southeast. Mild tonight, with lows 8-12 degrees above normal in
the mid to upper 60`s.
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
Unsettled conditions continue into Friday as the upper low
lingers w of the area, but overall moisture transport should
diminish, with the heavy rain threat diminishing. The upper low
begins to fill and lift n by Saturday resulting in gradually
The sky remains mostly cloudy to overcast through the period. High
temperatures range from the upper 70s to low 80s, with lows
generally in the 60s.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Anomalous upper low will make its way through the eastern Great
Lakes Sat night/Sunday and into New England by Monday where it
becomes more of an open wave/trough. This feature then moves off the
Northeast coast early next week. Based on the latest model
guidance...have slowed the timing of pcpn exiting the FA with chc
pops (30-50%) lingering across eastern areas Sat night...diminishing
to slight chc pops across eastern areas by Sun eve. Will maintain
dry wx Monday, then a lot of uncertainty develops by Monday night
into the middle of next week. There`s the potential for the remnants
of the upper low/trough to linger offshore (providing moist
onshore/easterly flow locally) and also uncertainty with regards to
the eventual track of TS Matthew. Will carry low end pops for now
Tue-Wed. Highs through the period mainly in the 70s. Lows in the
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Low pressure remains west of the region today, with high pressure
anchored well ne of the area. This continues to steer a moisture
rich airmass into the region and showers and iso tstms are
increasing in coverage this afternoon. Cigs are variable this
afternoon, vfr at most sites, mvfr at orf, and ifr at SBY. Expect
vsby to fall to 1-3sm in heavier rain. An ene wind of 8-15kt is
observed across the region, locally gusting up to 25kt along the
coasts of se VA/ne NC, and stronger at SBY with a sustained speeds
~20kt, and a recent gust up to 35kt. Areas of showers/embedded
tstms should continue through the evening, before gradually
shifting to the nw later tonight into Friday morning. Cigs likely
remain ifr at SBY through tonight into Friday morning, with ifr
cigs developing at RIC later tonight. Some fog is possible later
tonight, with vsby generally 2-4sm. Unsettled conditions persist
Friday afternoon and evening, before gradually improving Saturday
through early next week as upper level low pressure lifts n of the
Latest analysis shows surface low pressure from the SC piedmont to VA,
with strong/anomalous surface high pressure (1035 mb+) centered over
eastern Canada. The pattern today and tonight will feature this strong
high building over eastern Canada, ridging into New England and the northern
mid-Atlc region. A persistent/strong E/NE flow will prevail over northern
portions of the marine area and have upgraded far northern coastal waters to
a Gale Warning for today/tonight based on pattern with the surface high
building to near 1040 mb). Elsewhere, have added several more zones to SCA
headlines as winds gradually taper off to the 10-15 KT in NC and for the
upper James. NC coastal waters still expected to have seas build to 5 ft
so only zones that will not have any headlines will be the upper James
and the sound.
Winds diminish from S to N tonight and for all areas on Fri as the surface
low lifts N and pressure gradient weakens. Coastal seas will diminish
but still remain elevated at 4-6 ft into Fri night and possibly Sat due to
residual swell. SSE flow expected Sat leading to sub-SCA conditions elsewhere
with 1-2 ft waves over the Bay.
The synoptic pattern with strong High pressure centered over
eastern Canada with a slow moving boundary/sfc low pressure inland
over the Carolinas/Mid-Atlantic will continue to bring persistent
ENE flow to the area today/Fri. Departures avg 1.0 to 1.5 feet for
the most part.
Have expanded Coastal Flood Advisories to now include all zones in
adjacent to the Bay and the James/York/Rappahannock River...with
ocean side of the eastern shore also included. Many areas in the
lower Bay to fall a little shy of criteria with the high tide this
morning, but should see departures rise a bit more by this
aftn/tonight/early Fri and have the advisory to cover the 2nd high
tide overnight/early Fri. Will likely need to extend these
advisories into Fri night and possibly Sat as offshore seas
remain elevated and water is expected to struggle to exit the bay
for several days. Chance for moderate- severe flooding is low,
best chance would be across ocean side of the Accomack VA and
Worcester MD by Fri.
MD...Coastal Flood Advisory until 11 PM EDT this evening for MDZ024-
Flash Flood Watch through late tonight for MDZ021>025.
Coastal Flood Advisory until 8 AM EDT Friday for MDZ021>023.
VA...Flash Flood Watch until midnight EDT tonight for VAZ048-
Coastal Flood Advisory until 4 AM EDT Friday for VAZ075>078-
Coastal Flood Advisory until 1 AM EDT Friday for VAZ095>097-
Coastal Flood Advisory until 11 PM EDT this evening for VAZ099-
Flash Flood Watch through late tonight for VAZ075>078-083-085-
MARINE...Small Craft Advisory until 1 AM EDT Saturday for ANZ652-654.
Small Craft Advisory until 6 PM EDT Friday for ANZ656-658.
Gale Warning until 4 AM EDT Friday for ANZ650.
Small Craft Advisory until 7 PM EDT this evening for ANZ632-
Small Craft Advisory until 1 AM EDT Friday for ANZ634-635.
Small Craft Advisory until 7 AM EDT Friday for ANZ630-631.