537
FXUS61 KOKX 242045
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
445 PM EDT Fri May 24 2024

.SYNOPSIS...
High pressure will be in control through tonight. Weak low pressure
then passes to our north Saturday night into Sunday. A series
of frontal systems impact the area during the first half of next
week. An upper level disturbance may impact the area towards
the end of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A weak cold front or trough will be in the vicinity through the
night, but with little consequence as it remains dry. NBM looked
good for low temperatures, but blended in MAV MOS for the spots that
typically experience stronger radiational cooling.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Upper ridging approaching from the Great Lakes moves across the area
Saturday and begins to weaken. Weak high pressure remains at the
surface to start, but a warm front associated with weak low pressure
shifting east out of the Great lakes reaches us late in the day.
CAMs show a weakening line of convection moving into the upper
ridging and reaching the forecast area very late in the day/early
evening. Some timing differences exist, with the 3km NAM a few hours
behind most guidance. Went along the lines of NBM for timing. CAPE
will be lacking during this period, with up to around 500 J/kg
SBCAPE early in the evening and limited to well NW of the city.
Speed and directional shear will be lacking too, so while there may
be a rumble of thunder possible, not expecting severe thunderstorms
with whatever manages to reach the forecast area. Highs will be
above average, ranging mostly in the mid 70s to lower 80s. Low
temperatures will above normal too with partly to mostly cloudy
conditions.

The trailing cold front of the weak system will be over us Sunday
morning. It may linger over the forecast area all day or slowly
drift just offshore. Either way, this puts at least part of the
forecast area in the warm sector for some portion of the day. Don`t
think we`ll see anything in the morning, but as CAPE increases,
there could be isolated/scattered thunderstorms in the afternoon and
evening. Better chances would be away from the coast where
instability will be greater. Shear profiles not impressive once
again, so not anticipating severe weather. High temperatures a
degree or two warmer than on Saturday and starting to feel a little
muggy with dewpoints around 60.

A stronger storm system strengthens to our west Sunday night.
Another warm front will therefore approach during the night. Lift is
lacking, but should increase along with moisture late at night ahead
of the approaching front. PoPs therefore capped at chance.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...

Key points:

* Generally above normal Monday through Wednesday. Tuesday is
  expected to be the warmest day. The end of the week cools
  down a bit.

* Unsettled Monday-Wednesday with multiple frontal systems
  affecting the area.


An amplifying upper trough across the Great Lakes and into the
Northeast during this period will feature some potentially
active weather through midweek. Thereafter, it gets a bit more
uncertain with an omega block setting up across the Lower 48,
featuring a potential upper low cutting off across Northeast.

Stayed very close to the NBM during this period, but did try to
reflect some trends noted in the 12Z guidance. At the onset of
the period, another strong low lifts across the Great Lakes and
into Canada, sending a moisture-laden frontal system into the
area Monday into Monday night. Global models generally support
the highest rainfall amounts from NYC and points north and west
with 1-2 inches. The Canadian is producing quite a bit more, but
is an outlier at this time. WPC has portions of this area under
a Slight Risk of Excessive Rainfall. The heaviest rain (w/embedded
thunderstorms) looks to spread in across western area Monday
afternoon, but may take until evening to get out across eastern
LI and SE CT. Still though, there will be a chance of showers
and plenty of clouds. The trend here has been slower, so this
will need to be watched as well.

Warm front/cold front exits the area Tuesday morning with what
should be mainly a dry day outside of a late day shower. Where
it gets interesting, is with another shortwave dropping into the
upper trough over the Great Lakes Tuesday and into the area on
Wednesday. There are some timing issues, which could become
significant in how quickly the airmass can destabilize ahead of
an approaching cold front on Wednesday. The 12Z GFS has very dry
profiles and a mid level cap, with a strengthening mid level
flow. At this time, just have a mention of scattered convection.

For the end of the week, high pressure builds in on Thursday,
but this will depend on how quickly the energy exits to the
east and there are differences. The 12Z ECMWF cuts off an upper
low across the area by Friday. This could result in clouds and
showers each afternoon.

Temperatures do cool down a bit at the end of the week, closer
to normal, but with an amplifying upper trough an/or closed
low, this may start trending down.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR through the TAF period.

W-SW winds except S-SW near the coast. Winds light and variable
tonight (mainly N). N winds Sat morning becoming S-SE on
Saturday. Uncertainty remains high as to how far inland any sea
breeze can get.

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

No unscheduled amendments are expected.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

18z Saturday: VFR.

Sunday: Morning IFR/MVFR possible coastal terminals...otherwise
VFR.

Monday: Chance of showers and possibly a tstm, with MVFR cond
possible.

Tuesday: VFR.

Wednesday: Chance of showers and possibly a tstm, with MVFR cond
possible.

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

&&

.MARINE...
Sub-SCA conditions are expected across the forecast waters
through Sunday night with a weak pressure gradient and lack of
significant swell.

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. Winds and seas come down
by Tuesday  morning.

&&

.HYDROLOGY...
A frontal system will impact the area Monday into Monday night,
potentially bringing several rounds of moderate to heavy
rainfall. There is a great deal of uncertainty with where the
axis of heavy rain will fall, however the highest chances will
be for the higher terrain north and west of NYC. The Weather
Prediction Center has placed most of the area in a marginal risk
for excessive rainfall, with areas north and west of NYC in a
slight risk.

&&

.TIDES/COASTAL FLOODING...
A southerly flow at 5-10 kt and a southerly swell of 1 ft 9s
should keep the rip current risk low through Sunday. This is
also supported by latest RCMOS at area beaches.

&&

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

&&

$$

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