341
FXUS61 KOKX 300737
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
337 AM 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 /THROUGH TONIGHT/...
Some showers continue over far eastern CT likely associated with
some shortwave energy rounding the base of the upper level ridge.
With some elevated instability available, isolated thunder has been
observed. A chance of showers will continue through about 09z this
morning, with a slight chance of some more thunder. Any lingering
showers are likely out of the area by mid morning the latest.

The back door cold front has now stalled just southwest of our area.
This boundary will linger there or just over southern parts of our
area through the day today. Aloft, the upper level ridge axis will
move overhead this morning.

Tricky temperature forecast again today with the nearby lingering
boundary. Temperatures will likely be much cooler than yesterday.
The eastern 2/3 of the area should top out in the low 60s, with mid
to upper 60s for NYC, northeast NJ.

A frontal wave 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 /WEDNESDAY 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 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 MONDAY/...
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 /08Z TUESDAY THROUGH SATURDAY/...
A back door cold front becomes stationary to the south and west this
morning. A weak wave of low pressure passes across the terminals
this evening.

IFR ceilings across NYC terminals and western Long Island terminals
to start early this morning. MVFR ceilings are occurring at KSWF and
KBDR. IFR may become more widespread towards day break with KGON
likely staying MVFR. There is potential GON stays VFR through day
break. Ceilings should then gradually lift back to MVFR 14-16z with
potential of VFR returning in the afternoon (19-21z). MVFR should
return tonight after 00z, but exact and extent is uncertain.

Showers are possible this evening and an isolated thunderstorm
cannot be ruled out.

E-ENE through the TAF period mainly 10 kt or less. The flow should
begin to back towards the NE or NNE this evening into tonight.

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

IFR ceilings should develop at TEB 08-09z.

Timing of improving flight categories may be off by 1-3 hours.

Adjustments to timing of showers this evening possible. An isolated
thunderstorm cannot be ruled out.

OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...

Tuesday night: MVFR/IFR conditions with showers possible.

Wednesday: Becoming VFR. Chance of a shower early.

Thursday-Friday: VFR.

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

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...JT
SHORT TERM...JT
LONG TERM...JE
AVIATION...DS
MARINE...JE/JT
HYDROLOGY...JE/JT