000
FXUS61 KOKX 142054
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
354 PM EST Tue Nov 14 2023
.SYNOPSIS...
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High pressure builds in from the west through tonight,
eventually moving offshore on Wednesday. High pressure will
continue moving offshore Wednesday night through Thursday. High
pressure exits into the Atlantic Thursday night into early
Friday. A cold front and coastal storm affect the area Friday
night through Saturday. High pressure builds in for the second
half of next weekend into the beginning of next week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Increased clouds again for late this afternoon into early this
evening in the forecast database. Cloud coverage still expected
to be on a decreasing trend overall going through the evening.
Strong high pressure builds in from the west through tonight.
Mid level ridging will provide subsidence and keep sky conditions
mostly clear tonight. However, a steep pressure gradient
between the high and low pressure well out into the Atlantic
will keep gusty NW flow going into early this evening.
The northerly flow will eventually weaken with warmer air
advecting in at 850mb as ridging continues tonight. With the center
of high pressure moving into the region by early Wednesday,
winds will diminish late tonight with boundary layer decoupling.
More efficient radiational cooling can be expected as a result.
This will convey a more vast range of low temperatures late
tonight into early Wednesday morning spatially across the
region.
The relatively colder MET and ECS guidance were used for the low
temperature forecast tonight with some further adjustments downward
across the interior and rural areas, including Pine Barrens of Long
Island. The forecast lows range from the lower 20s across parts of
the interior and rural sections of Eastern Long Island in the
Pine Barrens to upper 30s along the parts of the immediate
coast as well as much of NYC. Compared to Monday night, tonight
is expected to have quite a bit more frost formation. Much of
the forecast region is forecast to have frost develop.
Widespread frost is expected across much of the interior and
Pine Barrens of Long Island.
In areas where growing season is still active (Hudson NJ, Southern
Nassau NY and NYC), the frost is only expected for a part of the
area with overall patchy coverage, not enough to warrant an
advisory. Lows in these areas will range from the upper 30s to near
40.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
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The strong high pressure area will eventually move offshore on
Wednesday.
Mid level ridging and negative vorticity advection will keep
subsidence and for sky conditions to remain mostly clear much of
Wednesday. Light winds Wednesday morning will eventually
increase and become more southwesterly in the afternoon. With
limited vertical mixing, forecast high temperatures will be
similar to those of the previous day, ranging from the upper 40s
to lower 50s but with some mid 50s for parts of NYC and
Northeast NJ. Some increase in clouds is expected for the latter
half of the afternoon.
For Wednesday night, warm air advection weakens. Mid level flow will
be quasi-zonal without much change in 500mb height. High pressure at
the surface moves farther offshore. Low level SW flow remains.
Surface flow remains up and more clouds are expected in
coverage so radiational cooling will be less especially along
the coast. A frontal system will be passing well north of the
region. Lows will be relatively warmer than the previous night
as a result. A blend of MAV and MET guidance was used for
forecast lows, ranging from the around 30 for the interior and
rural sections of Eastern Long Island within the Pine Barrens to
mid 40s for parts of NYC.
For Thursday, nearly zonal flow remains with some slight ridging in
the mid levels. At the surface, high pressure will continue moving
offshore. The increased ridging is forecast to make for a mostly
sunny day. Some more low level warm air advection is forecast
and while vertical mixing will be relatively similar to the
previous day, the temperatures will be warmer at the top of the
mixed layer. So, mixing adiabatically down is forecast to
result in temperatures substantially warmer than the previous
day. A blend of MAV, MET and NBM was used for forecast high
temperatures, ranging from the mid 50s to lower 60s.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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A mid/upper-level ridge overhead Thursday night exits to the east
and loses influence on Friday. Clear skies will be the norm across
the area Thursday night with light southwest winds. Some radiational
cooling will be possible, but Thursday night will be warmer than
Wednesday night due to increasing clouds and gradually strengthening
southwest winds in the early morning on Friday.
A sector of the southern jet stream is expected to phase with the
northern jet stream, leading to a stronger jet streak in the region.
This will allow a weak coastal system off of the south Atlantic
coast to rapidly strengthen as it tracks northward along the
Atlantic coast. The placement of this jet streak and the coastal low
vary among the available 12Z guidance, but most solutions now point
towards the coastal system tracking farther out to sea which means
POPs have been lowered in this forecast package to the
prior morning forecast package. It appears the 12Z GFS is the
outlier, still leaving the system with a track closer to the coast.
In that scenario, POPs may need to be raised. POPs are 40-50% for
much of the area early on Saturday with the eastern end of Long
Island and SE CT seeing increased chances of 60-70% due to their
proximity to the coastal low.
The strengthening coastal low to the south will also increase SW/S
winds from a stronger pressure gradient with breezy conditions
expected to develop on Friday, with the strongest winds in the
eastern part of the CWA. The stronger winds will also help mix down
warm temperatures aloft, likely leading to Friday afternoon being
around 10 degrees above average in the low/mid-60s.
A cold front will follow the quickly exiting coastal low with only
light precip expected along the front Saturday afternoon/evening. At
the same time an upper/mid-level trough will begin to rapidly
strengthen. Breezy NW winds following the frontal passage Saturday
night into Sunday will allow the area to quickly dry and cool with
clearing skies.
Skies remain clear with a strong trough aloft with surface high
pressure building at the surface on Sunday. A northwest wind will
reinforce colder air in the region. Sunday night into early Monday
some mid-level positive vorticity advection and increasing amounts of
700mb relative humidities along the periphery of the upper-level
trough could lead to some cloud development. This may limit low
temperatures Monday morning, but still expecting lows in the mid-30s
to upper-20s. Have blended in some 75th percentile NBM to hint
towards slightly warmer overnight lows due to partly cloudy skies
somewhat limiting radiational cooling.
Clear skies return on Monday with surface high pressure remaining in
place. The upper-level trough is expected to exit eastward Monday
night into Tuesday as a ridge inches closer from the west.-- End Changed Discussion --
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
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High pressure remains over the region into Wednesday afternoon.
VFR. Gusty NW to WNW winds have been slowly diminishing, with the
gusts expected to end 22Z to 23Z, possibly as early as 21Z to 22Z.
Northerly winds continue to diminish this evening, and become light
and variable late. A southerly develops late Wednesday morning.
NY Metro(KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments expected.
OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
Wednesday afternoon through Thursday: VFR.
Friday: VFR, lowering to MVFR or lower in showers late day into the
evening. S G15-20kt.
Saturday: Chance of MVFR or lower in showers, showers ending with
conditions improving late in the day. NW G15-25kt.
Sunday: VFR. W G20-25kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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SCA remains across all forecast waters through the rest of the
afternoon. For this evening until 10PM, the SCA continues on
the ocean due to some residual SCA gusts. Otherwise, non-ocean
waters are expected to have sub-SCA conditions.
A relaxing pressure gradient with high pressure moving overhead
will keep sub-SCA conditions on all waters late this evening
through Wednesday morning.
The pressure gradient increases Wednesday afternoon through
Wednesday night with high pressure moving offshore and a
frontal system passing well to the north of the area. Gusts up
to 20 kt are expected during this period with gusts up to 25
kt. SCA is probable, mainly for the ocean, but the 25 kt gusts
are forecast to be intermittent.
For Thursday through Friday, conditions on the waters are
forecast to remain below SCA thresholds.
Next potential for SCA conditions is Friday Night thru next
weekend with increasing S/SE winds and building waves ahead of
approaching cold front and then NE/offshore winds likely with
coastal low development. 25-28 kt gusts are possible on ocean
waters, primarily limited to Saturday night. Waves on Saturday
could build to 5 to 12 ft on the ocean waters, and up to 9 ft
are possible at the sound entrance. SCA conditions are expected
through early Monday afternoon with seas at or above 5ft,
dropping below 5 feet Monday night.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic impacts expected through the beginning of next
week.
&&
.TIDES/COASTAL FLOODING...
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With high astronomical levels with recent new moon, a few
locations along South Shore Bays, mainly in Southern Nassau NY
are expected to approach to just reach the minor coastal flood
benchmarks during their high tide. Roughly around 1.5 ft of
surge is needed for minor coastal flooding on average. There is
a coastal flood statement in effect from 7AM to 10AM Wednesday
morning for Southern Nassau NY. Other locations along the
coastlines are expected to remain below minor coastal flood
benchmarks.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 10 PM EST this evening for ANZ350-
353-355.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BR
AVIATION...MET
MARINE...JM/BR
HYDROLOGY...JM/BR
TIDES/COASTAL FLOODING...