586
FXUS61 KOKX 262320
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
720 PM EDT Sun May 26 2024

.SYNOPSIS...
A surface trough will linger over the area through this evening.
A stronger frontal system approaches from the west tonight and
will impact the region Monday into Monday night. A series of
reinforcing cold fronts will move across the area Tuesday into
Friday, followed by high pressure building in for the weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
For starters, with fog bank poised along the coast of Long
Island and NY harbor, have added patchy dense fog to the
widespread advection fog expected to move in over the next
couple of hours. In fact, a dense fog advisory is becoming
increasingly likely. There is some concern that mixing at the
base of the inversion could bring in some drier air. Latest
Hires models supporting the dense fog potential. In addition,
with loss of daytime heating and based on radar imagery,
isolated cells are weak and have removed thunder from forecast
this evening.

Surface trough lingers over the NW zones this evening. The
boundary lifts north as a warm front overnight, with another
weak warm front attempting to approach from the south. This in
association with a strengthening low over the Great Lakes. Warm
advection and increasing low level moisture ahead of second warm
front may be enough for a few spotty sprinkles or light showers,
especially towards daybreak Monday. Additionally the first
batch of convection from the west may sneak into the western
zones around daybreak.

The airmass will be more saturated and humid tonight with dew points
mainly in the 60s. This higher dew point air moving over the
colder waters in the 50s will help expand low clouds north and
westward through the night. Areas of fog are also possible, with
increasing confidence for some of it being dense. Lows will be
in the 60s.

Highs today will range from the 70s near the coast to the lower 80s
inland and portions of the NYC metro. Muggy conditions tonight are
excepted with lows in the 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
The warm front should lift north of the area Monday morning. The
low will continue moving out of the Great Lakes towards
southeast Canada through Monday evening. A pre-frontal trough
likely moves across the area Monday afternoon and evening
followed by the cold front Monday night into early Tuesday.

Here are some key messages on this upcoming system:

*Several rounds of showers and embedded thunderstorms are
 possible, first for mainly western areas, then spreading east
 in the afternoon/evening into Monday night.

*The primary threat appears to be minor/poor drainage flooding
 with a localized flash flood threat, especially where the heaviest
rain/training convection ultimately occurs. WPC continues to place
most of the area in a marginal risk for excessive rainfall, with
parts of Orange and Passaic Counties in a slight risk.

*While thunderstorms are possible, severe thunderstorms are not
 expected at this time due to limited surface instability.

*The showers/embedded storms quickly come to an end from west to
east Monday night as the cold front sweeps across the  region. This
will bring a return to dry conditions on Tuesday.

The ingredients for potential moderate to locally heavy rainfall
Monday into Monday night will be from a strengthening low level
jet advecting in +2 STD PWAT Atlantic/Gulf moisture. Elevated
instability, surface convergence along the multiple boundaries,
and large scale lift ahead of the large upper trough will
develop a few bands of showers with embedded thunderstorms. Most of
these will remain over the NW half of the forecast area in the
morning and early afternoon before shifting east later in the day
and into the evening. PWATs likely reach close to 1.75 inches, which
is close to the daily observed max for May 27th per SPC sounding
climatology.

The main forecast challenge will be where exactly the heaviest rain
will occur. Guidance continues to signal the overall best potential
to be north and west of the NYC metro, closer to interior Lower
Hudson Valley where upslope winds may enhance rainfall. However
individual CAMs/hi res models and global models are without a strong
consensus of where the heaviest qpf axis will be. With this said,
CAMs are overall greater with rainfall totals. The synoptic scale
forcing with a shortwave and approaching cold front during the
evening and overnight favors a relatively progressive area of
showers and embedded thunderstorms moving from west to east across
the area. Given this progressive nature coupled with the
aforementioned uncertainty along with the expectation that rainfall
will arrive in batches rather than one concentrated round of heavy
rain, there`s not enough confidence to issue a flood watch at this
time. Storm total rainfall amounts range from around 0.5 to 1.25
inches with locally higher amounts possible.

Any lingering rainfall should shift east of us early Tuesday morning
as the cold front tries to exit. The cold front may however hang up
near the coast as the main upper trough axis remains well to the
west. The deep moisture feed pushes offshore with the atmosphere
drying out for Tuesday. There will likely be less of an onshore
component to the wind, so have gone slightly above the deterministic
NBM for highs. Highs look to reach the upper 70s to the lower 80s
for most with middle 80s in NE NJ and parts of NYC.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A complex upper air pattern will feature a highly amplified
flow with upper troughs across the PAC NW and the NE quarter of
the CONUS, with ridging in between. These features translate
east through the period, with the upper ridging working into the
area by next weekend. The main focus continues to be with
shortwave energy diving into the base of the upper trough and
across the forecast area Wednesday, and a cutoff low forming
offshore at the end of the week.

For the midweek system, there continue to be differences with
the progression of shortwave energy within the upper trough. The
12Z GFS this time around has now resorted to a more progressive
system, while the ECMWF has remained fairly consistent with a
slower, stronger system Wednesday night into Thursday. The
latter of which reflects a surface low to the south of the area,
For the time, have stayed close to consensus and the NBM and
have maintained chances for showers and a few thunderstorms
areawide Wednesday into Wednesday night, however, confidence is
low. Chances look to diminish on Thursday but there still is a
mention due to uncertainty with the progression of shortwave
energy within the upper trough.

Attention then turns to the upper trough closing off just
offshore on Friday. There clearly has been an eastward progression
of this low the last 24h, in turn this looks to lead to a
mainly dry forecast with surface high pressure building into the
area over the weekend. There are then timing issues with a
frontal system progressing from the west which could bring
showers into the region next Sunday. Right now, expecting a
mainly dry weekend.

Highs in the long term will generally remain in the 70s each day,
with the warmest of the days Wednesday and again on Sunday.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A weak trough lingers over the western terminals tonight, with a
frontal system approaching on Monday and moving through Monday
night.

Becoming LIFR most arpts tngt. IFR or lower may then linger
thru the entire TAF period. Isolated shra/tsra development
possible for KSWF this eve. Potential for scattered showers
towards Monday morning push, with increasing likelihood of
rounds of SHRA and embedded TSRA Mon aftn into Mon ngt.

S-SE winds aob 10k tonight, increasing to 10-15G 20-25 kt on
Monday.

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

IFR (possibly LIFR) cig development likely for KLGA, KEWR, KTEB
thru 04z.

OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...

Monday Night: IFR/MVFR. Rounds of SHRA with embedded TSRA. SE
gusts 20-25kt likely for coastal terminal in eve. LLWS
potential with SSW winds of 40kt@2kft. SHRA/TSRA threat and LLWS
threat ends after midnight.

Tuesday: IFR/MVFR early, improving to VFR by noon. SW winds
10-15ktG20kt.

Wednesday-Friday: Late Night/AM MVFR/IFR stratus/fog potential.
Otherwise VFR, with chance of aftn SHRA/TSRA.

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

&&

.MARINE...
Dense fog advisory has been expanded to include all waters
overnight. Fog along the oceanfront will expand northward and
into the LI Sound and the eastern Bays over the next few hours.

The dense fog may last well into Monday, but will carry the
advisory through 10am Monday.

Otherwise, sub-advisory conditions tonight and Monday morning for
most of the waters. A strengthening SE flow on Monday afternoon
could into result gusts around 25kt on the ocean waters, mainly late
in the day, and west of Fire Island Inlet. Otherwise, seas probably
increase 4 to 5 ft Monday night, probably lasting into a part of
Tuesday. Decent chance for some gusts Monday night on the ocean
reaching 25kt. Being a marginal event that`s starting in the 3rd
period, will let subsequent shifts get a look at new guidance to
determine if advisories will be needed.

Otherwise, winds and seas will generally remain below SCA criteria
for the middle and end of the week.

&&

.HYDROLOGY...
A few rounds of showers and embedded thunderstorms with moderate
to locally heavy rainfall likely Monday into Monday Night.
Predictability with the location of the heaviest rain remains
somewhat low. Chances remain highest for the heaviest rain across
portions of NE NJ and the Lower Hudson Valley. This is where WPC
continues with a slight risk for excessive rainfall. These locations
are likely to see around 0.75-1.25 inches with locally higher
amounts possible. The rest of the area continues to be placed in a
marginal risk. The primary threat appears to be minor/poor drainage
flooding with a localized flash flood threat, especially where the
heaviest rain/training convection ultimately occurs.

&&

.TIDES/COASTAL FLOODING...
A strengthening southerly flow ahead of a frontal system will
allow for building surf on Monday with the rip current risk
increasing to moderate in the afternoon. While winds become WSW
on Tuesday, surf will be around 4 to 5 ft, continuing the moderate
risk. Beaches across Suffolk County may get to a high risk
Tuesday afternoon per latest RCMOS and NWPS probabilities.

Additionally, isolated minor coastal flooding will be possible
with Monday night`s high tide cycle. A statement may be needed
for the south shore back bays of Nassau County.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 10 AM EDT Monday for ANZ331-332-335-
     338-340-345-350-353-355.

&&

$$

SYNOPSIS...JC/DW
NEAR TERM...JC/DW
SHORT TERM...JC
LONG TERM...DW
AVIATION...JMC/NV
MARINE...JC/DW
HYDROLOGY...JC/DW
TIDES/COASTAL FLOODING...