043
FXUS61 KOKX 300534
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
134 AM EDT Tue Apr 30 2024

.SYNOPSIS...
A back door cold front becomes nearly stationary west of the
area into Tuesday. A couple of frontal waves then move through
the area Tuesday night and Wednesday. Weak high pressure settles
across Thursday, followed potentially by a back door cold front
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 THIS MORNING/...
With the loss of daytime heating and the front slowly sagging
south, look for just a couple of isolated showers perhaps as the
higher instability fields retreat to the west as there is no
longer enough support for any significant or organized
convection. A few showers can be seen on current radar imagery
in eastern CT. Keeping chance/slight chance precip probabilities
tonight as some shortwave energy moves into the upper ridge.
Chances of precipitation will be limited by the upper ridge in
the vicinity with dry upper levels and subsidence. Also, with an
east to southeast flow a low level inversion will set up. Low
level clouds have developed beneath the low level inversion,
starting along the coast this evening, then expanding westward
overnight.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
A nearly stationary boundary is expected to remain to the west
and southwest of the region, possibly moving slightly northward
as a warm front later Tuesday, and then shift northward as
developing wave along the boundary track through the coastal
areas Tuesday night and Wednesday. An east to southeast flow
behind the back door front will persist Tuesday through
Wednesday, keeping a maritime airmass across the region. After
well above normal temperatures Monday, temperatures will be
closer to seasonal normals Tuesday through Wednesday. The area
will be capped, and there is little to no elevated CAPE so will
not mention any chances of thunder.

&&

.LONG TERM /WEDNESDAY NIGHT 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 Thursday and Friday
look for mainly dry conditions. A warm front lifts north of the area
Wed night into Thursday. After seasonable temperatures Wednesday
night, temperatures should be able to get above normal once again
during Thursday as 850 mb temps attempt to climb above 10 C once
again as heights build. With a weak pressure gradient in place an
onshore flow will attempt to develop during the day. This will make
the temperatures forecast difficult, especially closer to the coast.
Went above NBM for the most part with respect to temps, especially
further inland where the effects of any light onshore flow out of
the SE would be minimized. 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. For now have
kept PoPs minimal across northeastern portions of the CWA late
Thursday and into Friday, although a few sprinkles or light showers
cannot be ruled out but any moisture from the boundary should be
rather shallow. 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 /06Z 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 are beginning to develop across NYC terminals and
Lower Hudson Valley terminals. This trend is expected to
continue through 09z with expansion eastward towards KISP and
KBDR. Ceilings may remain MVFR at KISP/KBDR and there is a
chance KGON does not lower till near 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...

Higher confidence in IFR ceilings through 14-15z. Lower
confidence in visibilities through 12z. There is a chance
visibilities could be slightly lower than forecast at times
through 12z.

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