000
FXUS61 KOKX 032034
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
434 PM EDT Wed May 3 2023
.SYNOPSIS...
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Low pressure remains over the region before shifting offshore
late tonight into Thursday morning. A surface trough lingers
nearby through the end of the week before high pressure starts
to build in over the weekend. High pressure will then remain in
control into early next week before a potential frontal system
impacts the area late Tuesday into Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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Plenty of cloud cover across the interior as the closed upper
low continues to spin over the Northeast. The center drifts
toward the coast this evening, and eventually offshore
overnight.
Diurnal showers, enhanced by the cool pool and energy with the low,
have developed over much of Pennsylvania and Upstate NY and are
beginning to pivot into the area. Removed mention of thunder,
though a widely isolated rumble of thunder is possible, surface
instability across the Northeast is low or nonexistent per SPC
mesoanalysis.
The greatest coverage based on a consensus of the latest hi-res data
continues to be from around the NYC metro/Hudson River corridor west
into northeast New Jersey and the Lower Hudson Valley. Eastern Long
Island and southeast CT may even remain dry into the evening with
weaker lift and some mid-level dry air. Rainfall amounts will be
light (under a tenth of an inch) overall, although some isolated
spots could see a few tenths in a heavier downpour.
The upper low and associated surface low move offshore tonight.
A few showers continue to be possible overnight, especially along
and near an inverted trough that may set up NW of the offshore low.
Overall coverage should be isolated to scattered, especially
overnight. Lows will generally be in the 40s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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The streak of afternoon showers persists on Thursday as the low
pressure system that has meandered nearby much of the week is slow to
exit offshore.
The cyclonic flow continues as the H5 trough axis shifts just east
of the region Thursday morning, while the surface flow turns N or NE
as the surface low slips offshore and begins to deepen. Several
pieces of energy will continue to rotate around the upper low, along
with an inverted surface trough stemming from the backside. These
features support the development of a bkn/sct cu deck once again,
with scattered showers possible. Model soundings indicate weak
SBCAPE, perhaps up to a hundred J/kg, but lapse rates won`t be quite
as steep with the cold pool shifting east. Maintained a no thunder
fcst, but a couple of rogue lightning strikes aren`t out of question.
Any lingering showers in the evening largely diminish with loss of
daytime heating. QPF through Thursday night is light, under a
quarter inch everywhere outside of convective maxima, with most at a
tenth or less.
High pressure begins to build in from the west Thursday night,
though mostly cloudy conditions persist. Temperatures will remain
unseasonably cool for early May, with highs ranging from the mid 50s
to around 60, or about 10 degrees below normal. Lows Thursday night
fall into the 40s once again, perhaps the upper 30s in the far
interior and LI Pine Barrens. A consensus of bias-corrected short-
term guidance was followed for this update.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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This will be a relatively quiet period as heights build aloft
as a weak shear axis slowly translates east. Globals are in good
agreement in then taking an upper trough/closed low over the
Davis Strait back south across the Canadian Maritimes late in
the weekend into early next week. Depending on height falls
associated with this system and high pressure building in on the
backside across central Canada, will determine whether or not a
frontal boundary over the Mid Atlantic will be in close enough
proximity to bring showers to the region Tuesday night into
Monday.
In the meantime, Friday will feature plenty of clouds with
plenty of low-level moisture left behind across the Northeast
and eastern Canada behind the departing upper low. There still
will be chance of mainly diurnally driven showers, mainly north
and west of the NYC metro. High pressure then slowly builds in
through the weekend. A weak surface trough (thermally driven)
across the area each afternoon will allow for daytime seabreezes
along the coast with plenty of sun. This will continue into at
least Monday.
Temperatures will warm through the weekend into early next
week, to about 5 degrees above normal. Inland locations will get
into the lower 70s by Sunday and lower to mid 70s Monday and
Tuesday. It will fall off closer to the coast, where it will be
in the 60s to near 70 with a more of a marine influence.-- End Changed Discussion --
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
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Broad area of low pressure remains over the area through the TAF
period.
3-4kft cigs expected over the NYC metro area through at least
the first half of the TAF period. As a result, expect the area
to be on the border of MVFR and VFR through this time. In
addition, some scattered showers will be possible throughout the
day, with the best chances for showers between 18z-00z. Showers
should begin to diminish into the evening but may linger
through 2-3Z . More widespread MVFR ceilings develop overnight
into Thursday morning. It appears that the MVFR cigs will
continue through the first half of Thursday, with VFR conditions
returning late in the 30 hour tafs.
WSW to SW winds at around 10 kt today. Winds veer to the NW and
N tonight and into the morning on Thursday at less than 10 kt.
....NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments may be needed today with the terminals between VFR
and MVFR conditions. Uncertainty remains as to the extent of
shower coverage throughout the day, however, the western most
terminals (including NYC) should see the most of the activity.
OUTLOOK FOR 18Z THURSDAY THROUGH SUNDAY...
Thursday afternoon: Any MVFR cigs become VFR late. Chance of
showers with MVFR conditions at times.
Friday: VFR. Chance of showers during the day. Light winds.
Saturday and Sunday: VFR. W/NW flow under 10 kt.
Monday: VFR. SW winds under 10kt.
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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Conditions on the waters will be sub-SCA through tonight.
Winds on eastern waters may increase Thursday and could reach around
20 kt in the afternoon. Seas may also build close to 5 ft east or
Moriches Inlet from an offshore low pressure late Thursday into
Thursday night.
Sub-SCA conditions are expected on all waters Friday through
early next week with high pressure slowly building in from thew
west.-- End Changed Discussion --
&&
.HYDROLOGY...
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Residual minor flooding along the Passaic River at Little Falls is
forecast to continue into this afternoon before falling below flood
stage.
Otherwise, no additional hydrologic impacts are expected through
early next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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Astronomical tides are increasing into the end of the week with
the approach of a full moon on Friday. The most vulnerable
locations along the south shore back bays, lower NY Harbor, and
Western Long Island Sound could see minor flooding benchmarks
touched with Thursday evenings high tide. There is a low chance
this happens as early as this evening.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR/DW
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...DW
AVIATION...BC
MARINE...DR/DW
HYDROLOGY...DR/DW
TIDES/COASTAL FLOODING...//