-- Discussion containing changed information from previous version are highlighted. --
435
FXUS61 KOKX 261142
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
742 AM 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
fronts follow Tuesday into Wednesday. An upper level
disturbance may impact the area towards the end of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Forecast on track this morning. Visibilities on Long Island have
improved the last few hours. Patchy fog is still possible early
this morning, but only anticipated low clouds over fog for the
next few hours.

Isolated showers are also possible as a shortwave continues
moving across the area. Heights quickly start rising behind the
shortwave leaving behind a surface trough. This trough likely
retrogrades inland this afternoon due to sea breezes and
synoptic SE flow. Low clouds may linger near the immediate
coast, especially eastern Long Island into the afternoon, but
daytime heating and some mixing should be enough to bring mostly
sunny conditions by late morning.

There is no discernible trigger for convection this afternoon
and evening. There is also some mid-level capping, so any
shower/storm focused on the weak trough will mainly be isolated,
Any convection quickly dissipates with loss of heating this
evening.

The airmass will become more saturated and humid this evening
with dew points in the lower 60s. This higher dew point air
moving over the colder waters in the 50s will help bring back
low clouds towards sunset near the coast. These low clouds will
expand north and westward through the night. Areas of fog are
also possible, but low confidence in the extent as winds above
the boundary layer will be increasing. This stronger flow may be
enough turbulent mixing to prevent any significant fog. These
trends will need to be monitored. If winds are slower to pick
up aloft, fog could become dense, especially near the coast.

A warm front associated with a strengthening low over the Great
Lakes begins lifting towards the region late. Warm advection and
increasing low level moisture ahead of the front may be enough
for a few spotty sprinkles or light showers, especially towards
day break Monday.

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 /MONDAY 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 has
 continued to place much of the area in a marginal risk for
 excessive rainfall with portions of NE NJ and Lower Hudson
 Valley in a slight risk.

*While thunderstorms are possible, severe thunderstorms are not
 expected at this time due to limited surface instability. The
 threat of severe weather is higher over the Middle Atlantic
 where greater surface instability is likely to be realized.

*The showers/embedded storms quickly come to an end from west to
 east late 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 west of the Hudson River corridor in the
morning and early afternoon before shifting east 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 this
potential to be well north and west of the NYC metro, closer to
interior Lower Hudson Valley. The system is just now getting
into range of the high resolution CAMs. The 00z HREF only goes
out to 00z Tuesday so it does not completely cover the system
yet. 00z HREF probabilities of observing greater than 1 inch of
rain in one hour are very low through 00z Tuesday. The only
areas it is signaling for a 10-20 percent chance are just west
of the CWA. The individual cams up to this point are varying
their depiction of where and when specific bands of convection
occur adding to the uncertainty. We should start to see a
better idea of the evolution of the convection with the upcoming
12z HREF and 00z Monday HREF. The synoptic scale forcing with
the 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.

Storm total rainfall amounts range from around 0.5 to 1.5 inches
with locally higher amounts possible.

Conditions dry out early Tuesday morning from west to east. The
cold front may 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 into 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 NYC metro.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Stuck somewhat close to the NBM/previous forecast for the long
term period.

The period starts off with a shortwave moving out of the Great
Lakes Tuesday night and across the local area on Wednesday.
This will result in some showers and possible thunderstorms for
the Wednesday and Wednesday evening period.

An upper trough move over the region on Thursday, however it
appears we remain mostly dry. As the trough moves off the
coast, a low associated with it will close off, however guidance
is showing this low closing off a bit further away from the
region than last night. So for now will keep POPs either dry or
at just a slight chance. Either way, right now it looks like a
drier end of the week and first part of next weekend than it did
yesterday.

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

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
A weakening cold front will stall near the area terminals
today.

VFR at most terminals, however, LIFR at KJFK and KGON with IFR
at KISP. These low cigs are due to low stratus/fog over the area
waters. Conditions are expected to improve around 14z.
Also, can not rule out a few isolated showers through 14z. A
return to VFR is then expected between 14-15z. IFR or lower
is expected to return again after 00Z. Higher confidence of
stratus after 00z Monday with lower confidence of fog.

Light and variable winds to start, then winds become S-SE around
10kt. Light and variable winds expected once again tonight.

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

Timing of improvement at KJFK may be off by an hour. Timing of a
return to IFR or lower tonight may be off by 1-3 hours.

OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...

Monday: IFR. Chc morning showers, then PM showers likely and
chc of TSTM. SE gusts 20-25kt possible for coastal terminals.

Tuesday: IFR/MVFR early, improving to VFR by noon.

Wednesday: Chance of aftn TSTM and MVFR.

Thursday: Mainly VFR. Slight chc shra/TSTM.

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

&&

.MARINE...
Dense fog is no longer anticipated on the south shore bays and
NY Harbor. The dense fog advisory remains in effect until 10 am
on the ocean and it is mainly for the ocean away from the
immediate coast. It is possible the Advisory will need to be
cancelled sooner especially if conditions improve.

A weak pressure gradient and lack of significant swell will lead
to conditions below SCA levels through Sunday night. A
strengthening S- SE flow on Monday could into result in marginal
SCA conditions on the ocean waters, mainly late in the day into
the first half of the night. 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
low, but should become better resolved over the next 12-24
hours. Chances remain highest for the heaviest rain across
portions of NE NJ and the Lower Hudson Valley. This is where WPC
continue with a slight risk for excessive rainfall. These
locations are likely to see around 1-1.5 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 southerly flow at 5-10 kt and a southerly swell of 1 ft 8-9s
will keep the rip current risk low today.

The rip current risk increase to moderate on Monday as SE winds
strengthen, building waves to 3 to 4 ft into the afternoon. The
risk may start out low in the morning before becoming moderate
in the afternoon. This forecast is supported by the latest
RCMOS.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 10 AM EDT this morning for ANZ350-353-
     355.

&&

$$

SYNOPSIS...BC/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...BC
AVIATION...BC
MARINE...BC/DS
HYDROLOGY...BC/DS
TIDES/COASTAL FLOODING...