421
FXUS61 KOKX 060559
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
159 AM EDT Thu Jun 6 2024

.SYNOPSIS...
A warm front approaches from the south tonight and lifts north
of the area Thursday morning. A cold frontal passage will follow
Thursday night. A broad area of low pressure meanders nearby
over southeast Canada Friday and into early next week. High
pressure follow for the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The forecast is on track with only minor changes needed.
Front edge of showers and thunderstorms associated with the warm
front are making their way through northwestern New Jersey as
of 11 pm. This should continue to move eastward through the
night. Previous discussion follows.

An approaching warm front over the Mid Atlantic states early
this evening will move across the area late tonight into Thursday
morning. A moisture-laden airmass with PWAT around 2 inches
with modest thermal forcing will produce widespread showers with
embedded thunderstorms. Latest CAMs show much of the activity
moving into western portions of the area around or just after
midnight. Rainfall rates will generally be less than 0.25"/hr
with localized higher amounts up to an inch/hr with stronger
embedded convection. Main impacts look to be minor nuisance
flooding, primarily in urban areas. Severe weather is not a
threat overnight. The bulk of the rainfall falls with the warm
front. There is also the potential for fog overnight, especially
at the coast as higher dew point air moves across the cooler
nearshore waters. However, confidence is low with SST in the mid
60s and the fact that it did not occur last night. Prefer to
see a larger difference between the SST and dew points.

Rain associated with the warm front exits far eastern LI and SE
CT by late morning. The forecast area will dry out for the
remainder of the morning into the early afternoon before
convection develops along and ahead of an approaching pre-
frontal trough. Airmass destabilizes in the warm sector with the
potential for CAPE values increasing to 1000-2000 J/KG north
and west of NYC by early afternoon, then shifting eastward
through the evening hours. The severe weather threat is low
with mid level winds around 30 kt, and CAPEs more typical of
heavy rain with slower updrafts. That being the case, should we
be able to achieve potential CAPEs in excess of 2000 J/KG, this
may be enough for a marginal severe weather. SPC has the forecast
area under a Marginal Risk with the exception of eastern LI and
SE CT. While rainfall will be heavy with any showers and thunderstorms,
storm motion will be west at 25 to 30 kt. This should limit the
flood threat to mainly the minor nuisance poor drainage variety,
but isolated flash flooding can`t be completely ruled out. The
threat ends by late evening Thursday.

Overnight lows will be in the 60s to around 70, which is above
normal by about 10 degrees. For highs on Thursday, went with the
warmer NBM guidance in the warm sector with highs in the low to
mid 80s from NYC and points north and west, and in the 70s to
around 80 elsewhere. It will be coolest along the immediate
south shore of LI.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Any lingering convection ends by late Thursday evening for
eastern LI/SE CT. An upper low over the eastern Great Lakes
drops into the Northeast during this time with the potential for
scattered showers Friday afternoon for the interior. It will
also be a bit cooler on Friday with the exception of coastal
locations that will be able to warm up to 75 to 80 due to a
more westerly flow. WSW winds on Friday may also gusts up to 20
mph in the afternoon.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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.

After Tuesday, global guidance varies. They agree on the meandering
low finally pushing out into the open Atlantic. They disagree on
what happens afterwards with some of the guidance hinting at a
ridging pattern taking hold, while others bring in another trough
from the west.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A warm front approaches, lifting north of the region this
morning, followed by a cold front this evening.

Conditions vary from VFR at KSWF to LIFR at KJFK. Most of the
terminals are either MVFR or IFR, which is what can generally
be expected, with LIFR condition likely at the terminals right
along the coastlines. Any restrictions to visibility look to
occur with heavier showers early this morning, but fog still
cannot be ruled out.

Embedded thunder will be possible early this morning but will
remain too isolated to include in the TAF at this time.
Steadiest of the showers exits around 10-12z this morning. We
get a break in the precipitation, then another round of
showers and thunderstorms is then possible this afternoon.
Higher confidence in thunder for this period and will continue
to carry a PROB30 for TSRA. Any storms will be capable of gusty
winds and heavy downpours.

Southerly flow persists today, speeds around or slightly above 10
kt. Winds tonight become more westerly behind the cold front.

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

Amendments likely due to changing flight categories. A
thunderstorm cannot be ruled out overnight, especially with the
steadier rainfall between 06Z and 12Z.

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

OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...

Thursday Night: Mainly VFR. MVFR or lower possible in showers
and thunderstorms early Thursday evening.

Friday: Mainly VFR. Chance of showers and thunderstorms for KSWF.

Saturday-Monday: Chance of MVFR in showers.

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

&&

.MARINE...
Fog may become an issue overnight as high dew point air moves
across the waters. However, with water temps on the ocean in the
mid 60s this did not happen last night. Confidence is low at
this time.

SCA has been issued for the ocean waters for Thursday and
Thursday night for marginal Southerly gusts 20-25kt and seas
building to 4 to 6 ft. Seas around 5 ft may linger into Friday.

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

&&

.HYDROLOGY...
Rainfall amounts of 0.50 to 1.00" with localized higher amounts
are expected overnight into Thursday morning. 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...
Have extended the ongoing Coastal Flood Advisory for coastal
Fairfield, Westchester, and S Nassau counties for this evening into
the Thu evening high tide cycle, and added the tidal waterways of NE
NJ to the coastal flood statement for this evening`s high tide
cycle. Elevated astronomical high tides associated with the new moon
combined with onshore flow will continue to support water levels
touching or just surpassing minor flood benchmarks in these areas.

It is uncertain whether the Fri evening high tide cycle will also be
impacted, as multiple high tide cycle surge events such as this can
sometimes last longer than model forecasts.

There remains a moderate rip current risk on the ocean beaches
through Friday due to building seas and a strengthening
southerly flow. There is a chance this will need to be elevated
to a high risk.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory until 2 AM EDT early this morning for
     CTZ009.
     Coastal Flood Advisory from 11 PM this evening to 3 AM EDT
     Friday for CTZ009.
NY...Coastal Flood Advisory until 2 AM EDT early this morning for
     NYZ071.
     Coastal Flood Advisory from 11 PM this evening to 3 AM EDT
     Friday for NYZ071.
     Coastal Flood Advisory from 8 PM to 11 PM EDT this evening for
     NYZ179.
NJ...None.
MARINE...Small Craft Advisory from 6 AM this morning to 6 AM EDT Friday
     for ANZ350-353-355.

&&

$$

SYNOPSIS...BR/DW
NEAR TERM...JP/DW
SHORT TERM...DW
LONG TERM...BR
AVIATION...BC
MARINE...BR/DW
HYDROLOGY...BR/DW
TIDES/COASTAL FLOODING...