-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 011843
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
243 PM EDT Wed May 1 2024

.SYNOPSIS...
A weak frontal wave continues pushing offshore early this
morning with high pressure returning this afternoon into
tonight. Another weak frontal system passes across the area
Thursday, followed by high pressure Friday into early Saturday.
A weak frontal system approaches Saturday and passes through
late in the weekend or early next week. A warm front approaches
late Tuesday.

&&

.NEAR TERM /THROUGH THURSDAY/...
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Temperatures a slightly higher where the sun broke up in some
spots, especially away from the coast. Increased hourly and high
temperatures a degree or so based on current trends. Also, added
a slight chance for showers across much of southern Connecticut
and central and eastern Long Island. Many of the CAMs and the
latest HRRR continue show the development of some showers out
that way later this afternoon. With the frontal boundary in the
vicinity, aided by some lift and convergence with the sea
breeze, it could provide enough lift for showers in this area,
possibly in.

A progressive and flat ridge will slide across New England
today with weak high pressure at the surface. Lingering clouds
this morning should give way to some sunshine, especially late
morning into the afternoon. Light NE flow to begin the day
should give way to a SE flow in the afternoon. There are hints
in some of the guidance for a passing shower in the afternoon
across interior CT. Feel this may be overdone, but did keep a
bit more cloud cover in this part of the region. Temperatures
are bit of a challenge again, but the usual warmer locations in
NE NJ, Lower Hudson Valley, and parts of NYC should be able to
reach the middle to upper 70s. Onshore flow should keep
locations further east a bit lower with highs in the middle to
upper 60s.

Some low clouds make a return tonight leading to mostly cloudy
conditions. The ridge axis slides to the east overnight with
another shortwave beginning to swing across northern New
England towards Thursday morning. Lows range from the middle to
upper 40s across Long Island and southeast Connecticut to lower
50s from the NYC metro on NW.
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&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
The shortwave moving across northern New England will send a
weak frontal wave across the region on Thursday. The energy and
lift from the shortwave passes to our north and east, so not
anticipating any showers. The main forecast challenge on
Thursday will be with high temperatures and the timing of a wind
shift associated with the frontal wave. The faster guidance
would allow the winds to become more westerly in the afternoon,
especially away from the immediate coast, giving temperatures a
boost.

The NBM deterministic and statistical guidance are once again
running at or below the 25th percentile of the NBM for highs
on Thursday. The NBM deterministic and statistical guidance
have verified too cool recently, especially in regimes where
there is a deeper mixing and a westerly downslope component to
the wind. Think this is another good case to blend in some of
the warmer values in the 50th percentile of the NBM for
locations away from the immediate coast. While the air mass is
not as warm as Monday, using the 50th percentile of the NBM
verified well. Forecast highs on Thursday are in the lower to
middle 80s across the Lower Hudson Valley, NE NJ, and much of
the NYC metro. Further east, highs are in the upper 60s to
middle 70s. The 75th percentile of the NBM is depicting even
warmer highs in the upper 80s for some of the warmer spots.
These are possible if the flow goes westerly several hours
sooner. Warmer conditions may also occur over Long Island and
southern CT if the flow ends up more westerly than anticipated
in the afternoon.

High pressure builds across New England Thursday night and
should remain in control through Friday night. There is some
uncertainty regarding any stratus development for Thursday night
into Friday morning as an ENE flow off develops. Will go with
increasing clouds, but keep the forecast mostly cloudy for now.
At least partial clearing is expected Friday afternoon, but this
will be short-lived as clouds begin increasing again from west
to east Friday night ahead of the next frontal system and
shortwave energy. Temperatures Friday should end up close to
seasonable levels.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
An upper level ridge builds over the area on Saturday as high
pressure continues to nose down from our northeast. A weak
frontal system approaches from the west and continues to weaken
as it runs into the high. This creates a bit of a tricky PoP
forecast for Saturday, but continued previous thinking of
keeping much of Saturday dry as the upper level ridge axis
doesn`t pass through until Saturday evening. Slight chance to
chance PoPs Saturday afternoon for western locations, with
increasing PoPs through the night, becoming likely after
midnight. PoPs then continue through Sunday night. There are
some hints from the latest guidance of increased convergence
from an inverted trough/strengthening low as the system moves
through Sunday evening. This would bring a period of some
heavier rain to the area. Current NBM probabilities of seeing 1
inch or more with this event are 20 to 15 percent from west to
east, with the 90th percentile PQPF over 48 hours showing 1.5 to
1 inch from west to east.

Dry conditions are expected by early Monday morning. Brief, weak
high pressure builds in, with a weak cold front/surface trough
potentially passing through Monday evening. Heights rise aloft
slightly on Monday and expecting mostly sunny skies. This combined
with a light westerly flow should lead to some above normal
temperatures Monday. Went closer to the NBM 50th percentile as the
deterministic was closer to the 25th percentile. This gives
widespread low to mid 70s across the area.

A warm front approaches the area late Tuesday. There remains
uncertainty as to whether the warm front will remain nearby or
lift to the north late Tuesday and will thus affect
temperatures across the area. Mid level energy from the west
will attempt to break down any riding in the mid levels.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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Weak high pressure remains just east of the area through this
evening, then gives way to a weak frontal system approaching
from the west. There is some uncertainty as to how quickly
the associated warm front/cold front get through the area on
Thursday, which could lead to wind timing and intensity issues.
The front may struggle to get east of the coastal terminals.

Mainly VFR for the remainder of this afternoon, the one
exception being KGON where occasional MVFR ceilings are
expected. Widespread IFR/LIFR conditions are the forecast to
develop this evening into the early morning hours Thursday.
Improvement to VFR is forecast to occur quickly after 12Z
Thursday.

SE winds generally 10kt or less through the overnight, then
gradually veering from west to east on Thursday as a frontal
system attempts to work across the area. The westerly wind shift
may remain west of the KLGA and KJFK for much of the day,
before going around in the early evening. There is fair amount
of uncertainty as to how far east the west winds get on
Thursday. W/NW winds 10-15kt G20kt are possible for those
locations that do come around.

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

There is only low to medium confidence on the timing of IFR
ceilings tonight.

The timing of the wind shift to the W/NW on Thursday could be
delayed significantly, especially at KLGA and KJFK. Warm front
could get hung up across the area during the daytime hours.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday Afternoon: VFR everywhere. Some W/NW gusts around
15-20KT in the afternoon.

Friday: VFR.

Saturday: Mainly VFR. Chance of showers and MVFR cond in the
afternoon, becoming likely overnight.

Sunday...Chance of MVFR or lower in showers. ESE winds G15-20kt.

Monday...VFR.

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

&&

.MARINE...
A weak pressure gradient remains in place, with an extended
period of conditions below SCA levels through early next week.
Seas may reach 3-4 feet late Sunday into Monday with a weak frontal
system moving through.

&&

.HYDROLOGY...
There are currently no hydrologic concerns through early next
week.

&&

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

&&

$$

SYNOPSIS...DS/JT
NEAR TERM...JP/DS
SHORT TERM...DS
LONG TERM...JT
AVIATION...DW
MARINE...DS/JT
HYDROLOGY...DS/JT