Area Forecast Discussion
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FXUS61 KAKQ 180805
Area Forecast Discussion
National Weather Service Wakefield VA
405 AM EDT Tue Oct 18 2016
High pressure settles just off the southeast coast overnight. The
high slides southeast of the area through midweek...bringing warm
and dry conditions to the local area through the work week. A cold
front crosses the region Friday, bringing near seasonable
temperatures back to the region for the upcoming weekend.
.NEAR TERM /THROUGH TONIGHT/...
latest wx analysis features ~1018mb Surface High pressure offshore
of the SE coast. Aloft, upper level ridging extends NE from the
Gulf Coast into the TN River Valley, with persistent area of upper
level low pressure now meandering near The Bahamas.
Very similar day weatherwise across the region today. Heights
build over the local area as the strong/anomalous upper ridge
builds across the Carolinas into the Mid-Atlantic Today. Building
heights and 850Mb temps warming to +15-17C (+1 standard deviation)
will push highs up about a category from yesterday`s maxima. Highs
today generally in the low to mid 80`s (slightly cooler immediate
coastal zones) under a clear to mostly clear sky. These temps will
be challenge daily record max temps at our local climate sites.
See Climate section below.
Continued clear and mild tonight, with lows ranging through the
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
The upper high becomes centered from the southeast into the
Mid-Atlantic on Wednesday, resulting in the warmest day of the
period. Record temperatures appear possible with highs climbing
into mid 80`s inland, again cooler along the coast. These forecast
highs are generally ~15 degrees above normal. A frontal boundary
drops into the northern Mid-Atlantic region Wednesday afternoon.
Higher dewpoints pool along the boundary to the north, resulting
in some marginal instability nudging south across the Maryland
Eastern Shore. However, with the upper ridge over the region, warm
temperatures aloft should suppress any convection Wednesday
afternoon across the northeast forecast area, and have maintained
a dry forecast. Mild again Wednesday night with lows generally in
the mid 60`s.
Upper trough digs from the High Plains into the Mid Mississippi
River Valley on Thursday...nudging the associated Sfc cold front
east to the Appalachians by Thursday night, and to just west of
the local area on Friday morning. Heights and 850mb temperatures
begin to decrease across the local area on Thursday ahead of the
cold front. Thus while temperatures will remain above normal,
expect temperatures to be about a category lower than those of
Wednesday. Highs u70s to l80s. Increasing clouds late and
continued mild Thu night. Lows around 60.
Front crosses the area on Friday, before pushing offshore Friday
evening. Typical timing differences persist with the frontal
passage, though continue to favor the more progressive ECMWF/EPS
solution to the slower/deeper GFS solution. Still, given
uncertainty, have nudged rain chances upward but kept in the slight
to low end chance for now. Also worth monitoring is the previously
referenced disturbance near the Bahamas. Incoming upper trough
will interact with this system, lifting the disturbance north-
Northeast, keeping it offshore of the SE coast up toward New
England Thursday night through Friday night, before the system
ejects into Atlantic Canada over the weekend.
Best lift and moisture remain removed to the north, nearest to a
wave of low pressure that will develop along the boundary along
the Eastern Great Lakes. Nonetheless, a period of rain appears an
increasingly good bet across the area Friday morning into the
afternoon as the front crosses into the area. Daytime temperatures
still several degrees above normal Friday, with highs generally in
.LONG TERM /SATURDAY THROUGH MONDAY/...
A return to more seasonable conditions expected from the weekend
into early next week. Lingering rain chances drop off on Sat as
drying WNW flow takes over. Cooler and dry wx Sat afternoon
Low Fri night from the l50s W to u50s at the coast. Highs Sat
from the l60s W to u60s E. Lows Sat and Sun nights from the m40s
(well) inland to the l50s at the coast. Highs Sun/Mon mainly in
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
As of 07Z...Surface high pressure remains in place along/just off
the Southeast coast with upper level ridging in place from the
southern Great Plains to the Tennessee Valley. VFR conditions in
place over area terminals expected to remain in place through the
06z Taf period w/mainly clear skies and a light southwesterly
flow. Anticipating mostly clear skies overnight. As with the
previous couple of nights, some patchy fog may develop over inland
locations closer to sunrise. Introduced a tempo MVFR for visibility
at RIC/SBY where patchy fog is most likely. Wind should limit any
fog near coastal locations. All fog should dissipate shortly after
sunrise and we will return to VFR conditions for Tuesday.
Outlook: Little change is expected in the overall pattern tonight
through Wednesday, as upper level ridge builds from the Lower
Mississippi Valley to the Carolinas. Dry weather/VFR conditions
are expected to persist through Thursday. The next chance for
showers arrives Friday as a cold front crosses the area. Dry
weather returns for the weekend.
Sfc high pressure will reside near the Mid Atlantic waters into
early Fri. S-SW winds aob 10kt through this morning with seas
2-4ft/waves 1-2ft. Meanwhile, a sfc low located just north of the
Upper Great Lakes will push across SE Canada today/tonight. The
sfc cold front associated with this system is expected to cross
the waters on Wed but weaken as it does so. The end result will be
a brief tightening of the sfc pressure gradient this aftn and
overnight with a slight increase in S-SW winds to 10-15kt all
waters. Seas continue to average 2-4ft/waves 1-2ft during this
surge. High pressure briefly rebounds over the Carolinas
Wed through Thu as another upper trough/sfc cold front approaches
the Mid Atlantic Region from the west. Winds will remain sly around
10kt with seas 2-3ft/waves 1-2ft.
The cold front is expected to cross the waters Fri late aftn/early
evening. Meanwhile, a coastal low well off the Southeast coast
(possibly becoming a tropical cyclone) stays well off of Cape
Hatteras as it gets pushed out to sea by the front. The interaction
of the cold front, coastal low, and cold Canadian high pressure
located behind the front will significantly tighten the sfc pressure
gradient beginning Fri aftn and persisting through at least the first
half of Sun before winds gradually start to diminish. Expect solid
SCA conditions (coastal waters/Bay/Sound/mouth of James River) to
develop quickly Fri evening with NW winds 20-25kt due to the presence
of strong cold air advection. In addition, building seas/swell from
the nearby low should be anticipated Fri through at least Sun morning.
Expect seas up to 4-6ft and waves of 3-4ft during strongest period
of winds Fri night (with the initial cold air surge). Another sfc low
pressure (similar to an Alberta Clipper) dives across the nrn waters
Sun night into Mon...allowing low-end SCA conditions to persist during
this time. Winds/seas/waves finally diminish Mon night into early next
week as high pressure returns to the area from the SW and cold air
advection processes wane. Winds generally W-WNW aob 15kt (15-20kt
coastal waters) with seas becoming 2-4ft/waves 1-3ft.
The experimental total water level hydrographs remain unavailable
at this time. We hope to have the information back online later
today. In the meantime, please refer to VIMS or MDL tidal data.
Very warm conditions this week with the possibility of challenging
some records listed below:
* Record Highs
* Tue (10/18) Wed (10/19) Thu (10/20)
* RIC 88 (1938) 87 (1938) 89 (1984)
* ORF 86 (2011) 87 (2007) 87 (1984)
* SBY 86 (1908) 84 (1938) 84 (1984)
* Record high Mins:
* Tue (10/18) Wed (10/19) Thu (10/20)
* RIC 67 (1980) 73 (2007) 68 (1916)
* ORF 68 (1980) 73 (2007) 70 (1916)
* SBY 70 (1975) 71 (2007) 68 (1916)