Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 031454
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
954 AM EST Sat Dec 3 2016

.SYNOPSIS...
High pressure builds towards the area this weekend, giving way to
a weak disturbance Sunday night into Monday. High pressure builds
in late Monday into Tuesday. A frontal system will approach for
the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mixing to around 900 MB this morning and winds aloft 30 to 35 KTS
as seen on VAD wind profile and model soundings and around 35 KTS
on 12Z OKX sounding. Wind gusts were running a little higher and
increased through this morning into the early afternoon. Toward
18Z winds aloft begin to diminish.

Adjusted sky cover through the day with a BKN to near OVC sky
inland and SCT to BKN along the coast, and CLR over the waters.
Maybe some variation through the day with sky cover.

Forecast temperatures and dew points on track as is high
temperatures for this afternoon.

Gusty NW flow continues due to a tight pressure gradient between
a strong area of low pressure departing into the Northern Atlantic
ocean and strong high pressure building from the west...but there
will also be some weak CAA as well.

Dry weather will prevail with any lake effect remaining to the
north and west. Highs will be in the mid to upper 40s in most
locations...however with the wind it will feel a bit
chilly...ranging from mid 30s inland to lower 40s at the coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Deep layered ridging builds towards the area tonight and OHD on
Sunday resulting in dry conditions. Gusts should diminish shortly
after sunset this eve along with clearing skies. Near the
coast...there may be enough wind to keep low temps around the
freezing mark...however little wind well inland will allow temps
to drop into the 20s overnight. Highs on Sunday will be slightly
below normal levels ranging from the low to mid 40s under mostly
sunny skies.

Upper trough lifting from the central Plains and Midwest regions
on Sunday will run into an amplified ridge resulting in flattening
of the flow with the best dynamics passing to the N and W of the
local area. However. a weak confluent flow over the Ohio Valley
Mon morning translates across srn New England with the exit region
of a 150+ kt H25 jet just to our south. Pcpn is expected to
overspread the area from W to E after midnight...although with the
system running into the upper ridge am not sure how robust amounts
will be...especially at the coast. Have trended higher with the
pops...but not ready to raise into the likely range just yet. NW
zones have the highest chance for QPF...thus highest pops are
there. Op EC is the wettest...NAM is driest and GFS is in
between. Interestingly...there are only 2 GEFS members that
support the wetter EC...but many of the ECEPS members have up to
1/10 inch QPF. If this trend continues pops will be raised. As far
as p-type...appears that it should start as snow everywhere...and
then gradually change over to rain from S to N as thicknesses
increase through the low levels in addition to warming during the
daylight hours. Low temps Sun night are tricky and may occur
earlier than normal depending on the amount of cloud cover during
the evening and evap cooling once pcpn begins. Pcpn tapers off W
to E late mon morning/early aftn.

Potential for generally up to an inch well NW of NYC with 1/2
inch or less at the coast before the changeover to rain. Monday
morning commute will likely be impacted.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Southern stream shortwave moves out of Mexico, and tracks across
Texas Monday before weakening as it moves quickly across the
southeast states Tuesday. Meanwhile, closed northern stream low
moves across central Canada, making slow progress toward the Great
Lakes mid week, then into New England late in the week.

Differences noted in position and strength of this impressive trough
is moves moves east late in the week.

At the surface, two areas of low pressure will form along a frontal
boundary. One over the Southeast that will push off the southeast
coast Tuesday night, then head east. The other will develop over
the Ohio Valley and pass north of the area into Wednesday. These
systems associated with southern stream shortwave mentioned
earlier.

Cold air damming signature noted for Tuesday, so precipitation may
start off as snow inland again, then change over to rain, with a
mixture of rain and snow Tuesday night. Again, QPF is expected
to be light.

Temperatures will be within a few degrees of normal through mid
week. Temps could jump slightly ahead of late week trough. Then
leaned toward colder numbers Friday, closer to WPC and away from
model blend.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Gusty NW flow today as high pressure slowly builds towards the
local area.

Wind direction at city terminals will average just to the right
of 310 magnetic, except at EWR where it could be right at 310
magnetic. Gusts will continue to increase this morning, with
highest gusts around 30 kt in the 15-20z time frame. Gusts will
start to decrease around sunset and diminish by 00z. NW winds
around 10 kt forecast overnight.

VFR through the TAF period with SCT-BKN cigs 4-6kft through this
evening.

.OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
.Sunday...VFR.
.Sunday night...MVFR possible after midnight in chance of light snow.
.Monday...Rain/snow mix possible early with MVFR possible in the
morning.
.Tuesday-Wednesday...MVFR possible in chance of wintry mix inland and
chance of rain near coast.

&&

.MARINE...
Forecast on track. Only update was to lower the seas across the
ocean waters east of Fire Island Inlet as strong northwest flow
keeping seas up to 7 FT.

SCA continues on all waters today under a gusty NW flow. Have
added ocnl gusts to 35 kt on the ocean waters as gale force gusts
are a possibility through the day...however do not expect them to
be frq enough for a gale warning. Winds begin to diminish this
eve...with winds falling below sca on the non-ocean waters by
10pm. Winds and seas are expected to remain elevated through the
night on the ocean. There is the possibility that gusts could
linger for a few hours Sun morning the eastern ocean zone
(Moriches Inlet to Montauk Point and out 20NM). Tranquil conds are
then expected through Monday night.

Expect conditions to deteriorate Tuesday into Wednesday as two
areas of low pressure approach the waters, and winds increase
ahead of these lows. Seas expected to build, but lowered forecast
below Wave Watch III output.

&&

.HYDROLOGY...
No significant precipitation (greater than a half inch) is
forecast through Monday.

Unsettled weather is possible mid to late week next week. However,
no significant precipitation (greater than a half inch) is forecast
at this time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ330-
     335-338-340-345.
     Small Craft Advisory until 7 AM EST Sunday for ANZ350-353-355.

&&

$$
SYNOPSIS...CS
NEAR TERM...MET
SHORT TERM...CS
LONG TERM...PW
AVIATION...FEB/DS
MARINE...MET/PW/CS
HYDROLOGY...PW/CS


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