National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 220515
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
115 AM EDT Mon Apr 22 2024

.SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
High pressure builds in from the west through today, and remains
in place Monday night. An afternoon thermal/lee trough sets up.

VFR.

Winds generally NW less than 10 kt overnight, but veer more to
the NNW toward morning. There is a chance of an afternoon
seabreeze, but looks to be late. Best chance at KJFK, KBDR, and
KGON.

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

There is a chance of a late day seabreeze at KJFK.


OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...

late Monday night-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
-- End Changed Discussion --

&&

.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...MET
MARINE...JE/DR
HYDROLOGY...JE/DR