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000
FXUS61 KOKX 220317
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1117 PM EDT Sun Apr 21 2024

.SYNOPSIS...
High pressure will generally be in control through Tuesday
before moving offshore late Tuesday and Tuesday night. A cold
front moves through on Wednesday, followed by high pressure to
close out the week. A frontal system may impact the area for
the weekend.

&&

.NEAR TERM /UNTIL 6 PM MONDAY EVENING/...
For this update, adjusted temperatures down for many locations,
especially across the interior and Pine Barrens region of LI.
However, have held off on frost advisories. The dry airmass
across the region and the gradient wind increasing a bit the
second half of the night are limiting the forecast coverage of
the frost. For Orange county NY, the western half of the county
is right around freezing for lows. This was a close call, but
being that it is the very beginning of the growing season, held
off on freeze warning.

Otherwise, skies will continue to clear overnight with lows
primarily in the lower 40s for the urban areas, lower and
middle 30s inland and Pine Barrens of eastern LI, and the upper
30s near the coast.

For Monday look for a good amount of sunshine and W to NW flow.
After a chilly start look for temperatures to recover with
mainly lower and middle 60s for most places. Went above blended
guidance / NBM based on synoptic regime, think there will be
enough of a NW flow for a large majority of the day to preclude
sea breeze advancement. Higher res guidance can overdo this at
times, but usually later in the season. However, if the synoptic
driven winds end up a bit lighter then the sea breeze can make
in-roads sooner, especially for coastal and southeastern sections.
Thinking the sea breeze happens very late towards 5 pm closer
to the coast and further east, if it even happens at all. One
could make the argument to go a few degrees warmer, but based on
some sea breeze uncertainty did not get more aggressive with
temperature forecast.

&&

.SHORT TERM /6 PM MONDAY EVENING THROUGH TUESDAY NIGHT/...
For Monday night look again for clear skies and light winds. Dew
point readings will likely be a shade higher with a little air mass
modification in all likelihood. With light winds more of a certainty
for the duration of the night and the lack of any cloud cover the
chances for more coverage in terms of frost, and perhaps minor
agriculture impacts increases some. Subsequent forecasts will need
to take a closer look with respect to this, but expect at least some
patchy frost across interior and rural locations. Lows will be
primarily in the lower and middle 30s once again further away from
urban locales, otherwise mainly upper 30s closer to the coast, with
40s in the more urban locations.  Went with MAV guidance for min
temp and dew points.

During Tuesday high pressure begins to get further east and should
be primarily offshore later in the day. A return flow gets
established quickly during the early portions of the afternoon with
the winds primarily off the colder ocean and out of the S and SSE.
This wind direction should result in a fairly wide temperatures
spread across the region for the afternoon as areas further west and
inland won`t get the entrainment of the wind off the colder ocean
compared to places further east and closer to the coast. Look for a
fair amount of sunshine across the region, with perhaps a few mid
level clouds encroaching into western sections later in the day.
Went closer to NBM 75th percentile for temps across western third of
the area, with some manual adjustments based on climo for this time
of year further east.

For Tuesday night with the high getting further east and the
approach of the next system from the west look for the winds to veer
more to the S and perhaps the SSW towards Wed AM. The column will
undergo more of a deep layered SW flow. Thus, clouds will increase,
especially above 5 kft or thereabouts. A lot will depend on the
speed and the timing of the approach of the frontal boundary, but
the column may moisten enough that some light showers or sprinkles
could very well break out before daybreak Wed, especially across
western most locations. Went slight chance to chance PoPs during
the pre-dawn hours towards sunrise.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Unsettled weather returns to start the period as a mid level trough
swings into the Northeast, pushing a surface front through on
Wednesday. Moisture appears limited though, PWATs under an inch and
surface dew pts mostly under 50F, so not anticipating a widespread
significant rainfall with this system. However, a hint of CAPE (a
hundred or two joules), steeper low level lapse rates, and speed
shear may allow for a few thunderstorms to develop ahead of the
advancing boundary in a low CAPE, modest shear environment. As of
now, the threat window looks to be in the later morning and
afternoon hours, depending on the progression of the front.
Ensembles keep QPF light with the fropa, mostly under a quarter inch
outside any convective elements.

The boundary likely moves through by the evening, and the trough
axis shifts east of the region Wed night. Ridging gradually builds
thereafter into the start of the weekend. Conditions dry out
Thursday as a 1030 mb surface high pressure builds in from the Great
Lakes. The high remains over the region Friday, before slipping
offshore and setting up southerly flow.

This weekend, a shortwave over the Central US will attempt to
ride up and over the amplified ridge into the weekend, bringing
a return to rain chances. This energy isn`t progged to move
onshore the West Coast until midweek, so will likely continue to
see varying solutions/timing until better sampling is achieved.
Capped PoPs at high chance (50%) to account for this
uncertainty.

As for temperatures, they look to average near, to just below,
normal for late April. Afternoon highs generally climb into the 60s,
with morning lows in the 30s and 40s. The coolest day in the period
appears to be Thursday behind the frontal passage, with highs
struggling to get out of the 50s for most. Frost/freeze headlines
may be needed a couple of mornings late in the week, at least for
portions of the local area. With only subtle adjustments, stayed
closed to national blended guidance for this update.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
High pressure builds in from the west through Monday. An
afternoon thermal/lee trough sets up.

VFR. WNW winds generally less than 10 kt overnight, but veer to
the NW in the morning. Chance of an afternoon seabreeze, but
looks to be late. Best chance at KJFK and KBDR.

     ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

There is a chance of a late day seabreeze on Monday. Highest
confidence is at KJFK.

OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...

Monday-Tuesday: VFR. Chance of showers Tuesday night, mainly
late.

Wednesday: MVFR or lower with showers. Isolated thunderstorms.
SW winds 10-15G20-25kt, becoming W-NW in the afternoon into the
evening.

Thursday-Friday: VFR.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
Primarily 2 ft ocean seas prevail through Monday night with high
pressure in control and a relatively weak pressure gradient
overall. Sub-small craft conditions will prevail across the
coastal waters through Tuesday, with perhaps more marginal small
craft conditions out on the ocean late Tuesday night as seas
begin to inch up along with winds out of the south.

A tightening pressure gradient will lead to increasing flow into
Wednesday. This should allow SCA conditions to develop on the ocean
with seas also climbing to around 5 ft. Non ocean waters may see a
period of 25 kt gusts Wed into Wed evening before subsiding behind a
cold frontal passage. Seas could linger near SCA criteria on the
ocean Wed night before diminishing, then sub SCA conditions expected
on all waters thru late week.

&&

.HYDROLOGY...
No hydrologic concerns exist throughout the forecast period.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JE/DR/DW
NEAR TERM...JE/DR/DW
SHORT TERM...JE
LONG TERM...DR
AVIATION...DW
MARINE...JE/DR
HYDROLOGY...JE/DR