314
FXUS61 KOKX 301820
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
220 PM EDT Tue Apr 30 2024

.SYNOPSIS...
A frontal boundary will linger just south of the area or over
southern portions of the area through the day. A frontal wave will
push the boundary offshore late tonight into Wednesday. Weak high
pressure remains in control the rest of Wednesday into early
Thursday, with a weakening low passing to the north later on
Thursday. Another back door cold front could potentially move
through on Friday. A weakening frontal system approaches for the
second half of the weekend, followed by high pressure building early
next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Lowered the cloud cover forecast for southern portions as per
latest satellite trends as well as bumped up the high
temperature forecast for parts of LI and Brooklyn and Queens to
account for more sunshine than previously anticipated. Partial
sunshine can still develop elsewhere later this afternoon with
maybe the exception being eastern LI and coastal SE CT where the
influence of a nearby weak low pressure center will be stronger.
A stationary front will otherwise linger nearby through the
day.

A frontal wave then passes through the area this evening and
overnight. Aloft, the upper level ridge breaks down and the flow
become more zonal. The CAMs are all in decent agreement with a
broken line of showers/thunderstorms moving into the Lower
Hudson Valley between 22z and 00z this evening and then
weakening significantly as it travels east. This is expected as
there may be some elevated instability to work with just west of
the area, but that falls off as you head east into a more
stable environment thanks to a cool onshore flow. Added a slight
chance of thunder for locations north and west of NYC. There
may be some brief heavy downpours as well north and west of NYC.
Due to the expected quick moving nature of any storms, flooding
is not expected at this time.

Overnight lows will be in the mid 40s to lower 50s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Weak high pressure builds in on Wednesday and remains in control
through early Thursday, with the flow aloft remaining relatively
zonal. A shortwave trough and associated weakening surface low then
pass to the north later on Thursday. This feature could bring some
showers to eastern portions of the area Thursday into Thursday
night.

There will be a bit of a warming trend into Thursday mainly for
locations away from the coast. Highs will be in the mid 60s to
low 70s for most on Wednesday. The surface flow becomes more
southerly on Thursday and there could be quite the temperature
gradient across the area. With an onshore flow from the start of
the day, Long Island and coastal CT likely top out in the upper
50s to mid 60s. Meanwhile, some locations in northeast NJ and
the Lower Hudson Valley have the potential to touch 80s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
An uncertain long term period in terms of the details, especially
with respect to the behavior of a back door cold front late this
week, along with the timing of a weakening frontal system towards
the second half of the weekend.

With respect to the beginning of the period for Friday look for
mainly dry conditions. Towards Friday much of the guidance is
now pointing towards the warm front that lift north of the area
to become stationary, then settle south as a cold front from the
north and northeast as high pressure along the Eastern Canadian
coast attempts to build south. This will likely aid in the cold
front getting driven further south and into the area Friday.
Temperatures overall into Friday should average a bit closer to
normal, with warmer temperatures further south and west and
cooler temperatures further north and east.

For the weekend the global guidance has gradually slowed the
progression of a weakening frontal boundary. This is mainly because
heights attempt to rise again across the area and this will make any
eastward progression of showers ahead of the cold front more
difficult. Have introduced slight chance and chance showers for the
day Saturday, but model trends and latest consensus pointing to
Saturday remaining predominantly dry. Thus, Saturday night into
Sunday appears to be the time frame for relatively higher chance
PoPs as the boundary slowly pushes into the region. Look for more in
the way of clouds, but a washout of the second half of the weekend
is looking less likely at this time as the upper level ridge over
the areas doesn`t really break down until the day on Sunday. Will
continue the shower chances through Sunday night, with PoPs
decreasing into Monday AM. High pressure should build behind the
weakened boundary later Monday and into Tuesday of next week. Warmer
temperatures may return on Monday as 850 mb temps warm once again.
This far out sfc winds are always in question this time of year, but
the guidance consensus is suggestive of a SW flow which would get a
large majority of the area above NBM guidance. For now have went
warmer than the NBM guidance for Monday as clouds should begin to
break.

&&

.AVIATION /17Z TUESDAY THROUGH SUNDAY/...
A wave of low pressure along a stationary front south and west
of the area this afternoon will pass to the south and east of
Long Island tonight. Weak high pressure follows for Wednesday.

This is a challenging ceiling forecast with mainly MVFR ceilings
across the area this afternoon, however, it has gone SCT across
the NYC terminals, where it will likely remain for the afternoon.
MVFR or lower conditions return tonight along with a chance of
showers. An isolated thunderstorm can not be ruled out for the
NYC and Lower Hudson Valley terminals from 23Z to 03Z. Any
convection will likely be in a weakened state across the
eastern terminals. Spotty showers are then expected for the
remainder of the overnight. VFR conditions return by Wednesday
afternoon.

Winds will be ENE-E through this evening, generally 10 kt or
less. The flow backs towards the N-NNE late tonight and early
Wednesday morning, with speeds 5 kt or less. SE winds generally
less than 10 kt will develop during the late morning and early
afternoon hours on Wednesday.

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

Occasional MVFR this afternoon, but mainly VFR.

MVFR returns tonight, but IFR is possible.

Timing of showers this evening could vary by 1-2 hours. A
thunderstorm is possible, but confidence is too low to include
in TAF at this time.

OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...

Wednesday Afternoon: Improving to VFR at all terminals.

Thursday-Friday: VFR.

Saturday: Mainly VFR. Chance of showers and MVFR afternoon into the
night.

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

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

&&

.MARINE...
A weak pressure gradient remains in place over the coastal waters
leading to an extended period of sub small craft conditions. Ocean
seas are expected to be at 2-3 feet through the remainder of the
week. Small craft conditions are not expected to potentially return
until late in the weekend.

&&

.HYDROLOGY...
There are no hydrologic concerns through the beginning of next
week.

&&

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

&&

$$

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