-- Discussion containing changed information from previous version are highlighted. --
272
FXUS61 KOKX 051139
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
739 AM EDT Wed Jun 5 2024

.SYNOPSIS...
High pressure moves farther out into the Atlantic today as a warm
front approaches the waters. This warm front moves in tonight and
then eventually northeast of the region along with the associated
cold front and low pressure on Friday. A broad area of low
pressure meanders nearby over southeast Canada this weekend and
into early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast mainly on track. Temperatures and dewpoints are within
a few degrees comparing hourly forecast with respective observed
values.

Fog south of Long Island with mainly low clouds along the coast.

From the morning into the start of the afternoon, the low
clouds and fog will be slower to dissipate for Long Island and
to the south but expecting a decrease in coverage for the latter
half of the morning.

In the afternoon, any remaining fog burns off and low clouds
scatter out for most locations expect along immediate coastline.

Only other weather feature for the afternoon into this evening
will be pop up showers and thunderstorms. These will be forming
well ahead of an approaching warm front. With combination of
where surface based CAPE will be relatively highest (up to a few
hundred J/kg) and where low level winds will exhibit more
convergence, that will be the western extremes of the region.
That is where there will be a chance for showers and
thunderstorms with otherwise in the nearby vicinity to the east,
a slight chance of showers and thunderstorms. Expecting any
convective activity to stay primarily to the north and west of
NYC.

Not much vertical forcing present, with actually more of an
upper level confluence pattern across the region. Upper level
ridge starts to move in by early tonight.

With mainly a dry day expected, high temperatures away from the
coast are forecast to rise into the low to mid 80s with the rest
of the area in the 70s. High temperatures forecast were from the
NBM.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Upper level ridge axis moves across tonight and then will shift
east of the region Thursday. It will be weakening as it does so.
An elongated NW to SE oriented upper level trough eventually
moves into the region Thursday night through Friday night.

With warm front and trough of low pressure moving in from the
south and west tonight, would expect rain showers to increase in
coverage. The passage of the warm front will make for a warm and
humid airmass to incorporate the area.

The forcing is not too strong and along with marginal elevated
instability, just left the thunderstorm mention of slight
chance. Low level omega increases more Thursday and with more
CAPE (up to around 1000 J/kg), will have a greater chance of
thunderstorms. Otherwise, showers are expected for much of
Thursday. For Thursday night, the shower and thunderstorm
activity is expected to decrease with the low and storm system
passing farther east of the region.

Mainly dry conditions expected for Friday and Friday night.
There could be a pop-up shower or thunderstorm across the
interior Friday afternoon into early Friday evening with upper
level disturbance aloft with the cutoff mid level low and its
associated cold pool. Mid 70s to lower 80s for max temperature
forecast Thursday and nearly same range for Friday, but a
greater fraction of the region has lower 80s compared to the
previous day.

High PWAT airmass still indicated by models with values up to
near 2 inches for late tonight into Thursday. This will make
for heavy downpours at times. See hydro section for more
details. These high PWATS are above the 90th percentile and even
the max according to the OKX sounding climatology from SPC.
Models indicate the PWATS to considerably lower across the
region Thursday night to around 0.7 to 1.2 inch. PWATS stay
under an inch thereafter through Friday night.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A relatively unsettled period this weekend into early next week with
an upper low cutting off and meandering over the Great Lakes region
and southeast Canada much of the time, with multiple vorticies
rotating around it that may periodically enhance rain chances
locally.

The broad low nearby likely instigates diurnal shower activity with
varying coverage each day, especially inland. As the cold pool moves
aloft, also can`t rule out the possibility of thunderstorms with
added instability. Global guidance continues to offer differing
solutions with any potential vorticies however and this will need to
be resolved for further clarity on when rain chances will be
highest.

Temperatures, while hampered by cloud cover and rain at times,
should still manage to get into the 70s and lower 80s most
afternoons, or about typical for this time of year. For now,
continued to cap PoPs at 50%, otherwise, national blend was followed
with subtle adjustments.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
High pressure shifts farther offshore today ahead of an approaching
warm front from the southwest. The front lifts through the region
Thursday morning.

Generally IFR this morning with low stratus and mist around.
Patchy fog, mainly at KHPN. Gradual improvement thru 15Z or so,
then VFR into early evening. Conditions likely decline to IFR
or lower once again tonight with showers developing. Embedded
thunder can`t be ruled out overnight into Thursday morning, but
chance is too low to include at this time. Steadiest of the
showers exits by mid morning Thursday, but improvement may take
until late morning or early afternoon.

Southerly flow persists into Thursday, speeds generally at or
under 10 kt.

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

Timing of return to VFR later this morning may be off by a couple
of hours.

Timing of category declines and SHRA late this evening may be off by
a few hours.

Isolated thunder possible overnight into Thursday morning.

OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...

Thursday: IFR early, improvement into afternoon. MVFR or lower
possible in showers and thunderstorms.

Friday: Chance of MVFR with showers and possible thunderstorms.

Saturday/Sunday: Chance of MVFR in showers.

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

&&

.MARINE...
Patchy dense fog with marine weather statement out until 10AM
for the NY Harbor, ocean waters 20 nm south of Long Island and
the South Shore Bays.

Conditions on the forecast waters remain below SCA thresholds
today through tonight. For Thursday through Friday night,
conditions could become marginal for SCA on the ocean.
Otherwise, non-ocean waters look to remain below SCA thresholds.

Conditions are expected to remain below SCA levels through the
weekend.

&&

.HYDROLOGY...
Rainfall amounts of 0.50 to 1.00" with localized higher amounts
are expected tonight into Thursday. Minor nuisance poor
drainage flooding will be the primary threat especially in urban
and low lying areas. The flooding potential will be limited due
to the expected speed of the showers and thunderstorms which
with a progressive pattern aloft, should be a relatively faster
steering flow.

&&

.TIDES/COASTAL FLOODING...
With a new moon this week, astronomical levels are elevated. An
onshore southerly flow will also support increasing surge and should
be sufficient to continue to get some of the vulnerable locations
along the western LI Sound and the South Shore Bays at or just above
minor flood benchmarks. A Coastal Flood Advisory has been issued
once again for coastal Fairfield, Westchester, and Nassau for this
evening`s high tide, with a Coastal Flood Statement in place for
coastal Queens, where the most vulnerable spots may see brief minor
flooding.

The persistent flow and astronomically high tides will likely lead
to additional minor flooding in subsequent evening high tides into
late this week.

There remains a moderate rip current risk on the ocean beaches
through Thursday due to building seas and a strengthening
southerly flow. The rip current threat magnitude is expected to
be higher on Thursday compared to today.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 9 PM this evening to 1 AM EDT
     Thursday for CTZ009.
NY...Coastal Flood Advisory from 9 PM this evening to 1 AM EDT
     Thursday for NYZ071.
     Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for
     NYZ179.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JM/DR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DR
AVIATION...DR
MARINE...JM/DR
HYDROLOGY...JM/DR
TIDES/COASTAL FLOODING...