Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 221056
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
556 AM EST Sun Jan 22 2017

.SYNOPSIS...
One area of low pressure will track from eastern North Carolina
northeast and off the Delmarva coast during today. A second
stronger area of low pressure over the Lower Mississippi Valley
will lift east northeast and across the Mid Atlantic region
tonight through Monday night. That low will move away just off
the New England coast during Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early this morning, a weak low pressure area was over ern NC.
Latest radar showed associated showers with this low were over
cntrl/scntrl VA ENE into the Lower MD and VA ern shore. These
showers will move away to the ENE or diminish to light rain or
drizzle later this morning into midday, as the low slides to
just off the Delmarva coast.

More showers and isolated tstms (acrs srn third of CWA) will
move ENE acrs the area fm late this morning into this evening,
due to good lift associated with a warm front aloft. Best
instability/shear for strong or possible severe tstms will
remain south of our CWA fm srn NC thru SC and into srn GA and
nrn FL today into this evening. SPC has a SLGT risk of severe
up to the Albemarle sound with a MRGNL risk acrs srn VA. Highs
today will range fm the mid 50s to the lower 60s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
The second area of low pressure will then lift fm ESE TN east
northeast and acrs the Mid Atlc region tonight thru Mon night.
This low and its associated warm front will provide strong lift
and pull in deeper Atlc moisture, resulting in showers (slgt chc
of tstms srn third) with heavy downpours possible tonight into
Mon morning. Lows in the upper 40s to lower 50s. QPF averages
between 0.5 inch to 1 inch with locally higher amounts possible in
any banded convection that may occur.

Sfc triple point progged to move north of the area Mon morning
with the trailing upr level low crossing the region Mon aftn
into early Tue morning. Pops will still range fm slght chc to
likely fm later Mon morning into early Tue morning, as the upper
level low slowly moves NE acrs the area to just off the NJ
coast. Highs on Mon will range fm the mid 50s to the mid 60s.

The low moves away just off the New England coast during Tue.
NW winds usher in drier air with increasing sunshine fm SW to NE
expected. Highs in the 50s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Overall, the models are in good agreement in the extended period
with only a few minor differences on the timing of the frontal
passage on Wed night into Thursday. But those differences are
minor and the 12z GFS has moved closer to the 00z ECMWF.

In the wake of the storm that will move through by Tuesday, a
shortwave ridge builds in Tues night into Wednesday. This will
allow for W to SW flow and should be a mild dry period. However,
the upper level pattern will begin to flip with a broad trough
developing over the eastern half of the country for the second
half of the week. This trough will enter the region Wed night
into Thursday as a sfc cold front slides into the area. This
front will be lacking moisture so have limited the pops to
slight chance to chance range. The best opportunity for rain
looks to be in the southeastern part of the area where a little
additional Atlantic moisture may be available. The timing on the
front is still a little up in the air. The ECMWF moves the
boundary through more quickly, while the GFS develops a wave and
is slower. But the trend has been toward the ECMWF timing so
focused the highest chance on Thursday. Will also need to watch
the timing on the cold air arrival as well as this could impact
the pcpn type, but for now don`t think the cold air will arrive
until after any pcpn is gone.

For Thursday night into Saturday, the region will be dominated
by strong NW flow which will drop temperatures back down into
the 40s for highs and lows in the upper 20s to low 30s. Have
kept the fcst dry too, but will have to monitor shortwaves
rotating through the upper trough as with this polar airmass, if
one of these waves amplifies a bit, some snow showers would not
be out of the realm of possibility.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A complex upper level trough is affecting much of the
Southeastern Conus and Mid-Atlantic early this morning. One wave
of low pressure is passing off the VA capes as of 06z with an
area of rain extending from central VA to the Ern Shore, with
some lingering showers across coastal SE VA/NE NC. IFR/LIFR
cigs prevail, although the lower cigs occasionally scatter and
reveal a 1.5-2.5kft layer, and this trend of lower cigs
occasionally scattering should continue the next 6-9 hours. Some
improvement in cigs is possible by aftn, but should fall again
tonight. Vsby drops to 1-3sm in heavier rain, with some fog
developing at ECG, which could expand to RIC/PHF after 09z.
Another wave of low pressure will bring occasional showers by
midday into early aftn, with the main frontal system lifting
across the region tonight into early Monday morning bringing
periods of moderate to heavy rain and reduced vsby. The wind
will generally be E to NE at 5-10kt today into this evening,
and is expected to increase to 10-15kt (locally 15-25kt at SBY)
late tonight into early Monday morning.

The upper system will lift across the area Monday aftn bringing
another chc of showers. Drier air gradually returns Monday
night into Tuesday as high pressure builds in from the NW. Low
pressure tracks through the Great Lakes Wednesday, and pulls a
cold front through the area later Wednesday night into early
Thursday. This will bring a chc of rain, before drier air
arrives from the NW later Thursday.

&&

.MARINE...
A complex low pressure system extends from the Gulf Coast States
across the Carolinas and into the Mid-Atlantic early this morning.
One individual wave of low pressure is pushing off the VA Capes
coast early this morning, with a stationary front extending back
into central NC. The wind is generally NNE 10-15kt N of the boundary
and SW 5-10kt S of the boundary. (Near) Coastal obs indicate vsby of
1sm or less S of Cape Henry, so the marine dense fog advisory has
been extended through 10 am for the ocean S of Cape Charles and the
Currituck Sound. Another wave of low pressure will track along the
front today, with the primary low tracking newd across the area late
tonight through midday Monday. A strong pressure gradient and modest
pressure falls develop late tonight through midday Monday and will
be strongest N of Cape Henry, and especially for the ocean N of
Parramore Island. The SCA N of Parramore Is. has been upgraded to a
gale warning for and E-NE wind of 25-35kt with gusts to around 40kt,
with the SCA to the S extending through Monday night as seas remain
aob 5ft. Seas build to 8-12ft N to 4-7ft S Monday in response to the
period of strongest wind. SCA flags have been issued for the
Bay/Lower James. The wind will be strongest in the Bay N of New
Point Comfort, and low-end gale gusts are possible N of Windmill
Point. The low stalls in vicinity of the NJ coast Monday aftn into
Monday night as high pressure builds in from the NW. The wind should
by NW 10-15kt/15-20kt ocean. High pressure gradually builds into the
region Tuesday night and slides offshore Wednesday ahead of a cold
front. This cold front crosses the coast later Wednesday night into
early Thursday.

&&

.TIDES/COASTAL FLOODING...
Low pressure pushes off the Delmarva coast late Sunday night
through midday Monday resulting in a brief but modestly strong
onshore wind. This has the potential to push tidal anomalies to
1.5-2.5ft above normal Monday into Monday night. Some locations
including the Atlantic coast from Chincoteague to Ocean City and
portions of the middle and upper Bay may come within 0.5ft of
minor flooding thresholds during high tide, but the current
forecast generally keeps water levels below minor flooding.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 1 AM to 1 PM EST Monday for ANZ630-
     631-634.
     Small Craft Advisory from 1 AM to 10 AM EST Monday for ANZ632.
     Dense Fog Advisory until 10 AM EST this morning for ANZ633-656-
     658.
     Small Craft Advisory from 1 AM to 7 AM EST Monday for ANZ638.
     Small Craft Advisory from 1 AM Monday to 6 AM EST Tuesday for
     ANZ654-656-658.
     Gale Warning from 1 AM to 1 PM EST Monday for ANZ650-652.

&&

$$
SYNOPSIS...TMG
NEAR TERM...TMG
SHORT TERM...MPR/TMG
LONG TERM...ESS
AVIATION...AJZ
MARINE...AJZ
TIDES/COASTAL FLOODING...AJZ



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