000
FXUS61 KOKX 301443
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1043 AM EDT Sun Apr 30 2023

.SYNOPSIS...
Deepening low pressure over the southeastern states tracks northeast
today and over the region tonight. The low then meanders over
the Great Lakes Monday before slowing moving over the northeast
through the middle of the week. An upper level trough will remain over
the area through the end of the week. High pressure begins to build
in over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast remains on track with generally minor adjustments to
temperatures and dew points.

The SPS for locally dense fog for Long Island will continue
through 11AM as fog slowly lifts.

Included Orange and Rockland counties in the Flood Watch in
effect this afternoon through this evening as antecedent rains
of 1-3 inches have primed the area ahead of additional
anticipated rainfall into this evening.

Low pressure heads our way today with its center passing through the
forecast area this evening. Moisture depth and lift will be on the
weaker side this morning, so mainly chances of light rain/drizzle
with areas of fog to start.

As the low center draws closer this afternoon, moisture and lift
will increase. PWATs rise to around 1.5 inches, and large-scale lift
is enhanced by frontogenetic forcing, isentropic lift, mid-level PVA,
and upper divergence from the left-exit region of a jet streak.
Looks like there could be two separate periods where rainfall could
be heavy at times. This first occurs during the first half of the
afternoon where CAMs appear to reflect the aforementioned sources of
lift via a WNW-ESE oriented band of moderate to locally heavy
rainfall pushing in from the south. Then as the low center draws
nearer, elevated convection becomes more possible during the second
half of the afternoon into the evening. A llj comes into play as
well, but would have more impact over the eastern zones. Given the
low FFG values (mainly 1-hr) in response to the 2 to 3.50 inches of
rainfall that has recently fallen for some areas, have decided in
collaboration with WFO PHI to go with a Flood Watch for flash
flooding potential for all of our NJ zones this afternoon and
evening. FFG values are higher elsewhere, and currently do not have
enough confidence for sufficient flash flooding coverage to warrant
expansion of the watch elsewhere. See the hydrology section below
for more details. Not expecting any severe-level wind gusts with any
thunderstorms that occur due to a low-level inversion that will
likely hamper the occurrence, so the main focus will be the flooding
potential. Elsewhere where there is no Flood Watch, expecting mainly
minor/nuisance flooding, but can`t completely rule out flash
flooding.

Rain ends by late at night with the low shifting north of the area.
It`ll be breezy during the afternoon and nighttime with a lull in
the winds during the evening N and W of the city. High temperatures
mostly in the low 60s.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Low pressure to our north will continue to interact with a large
closed upper low over the Great Lakes and Northeast on Monday and
Tuesday. Monday should start out dry, but there is a chance for an
afternoon shower, mainly NW of the NYC metro. Shower chances
increase late Monday night into Tuesday. This is due to  potential
of more organized energy and positive vorticity advection occurring
as the upper low nears. There also appears to be a bit higher
probability Tuesday morning NW of NYC with the aforementioned
energy. Chances persist into Tuesday afternoon with steepening lapse
rates from the cold pocket aloft and some limited daytime heating.
High temperatures for both Monday and Tuesday will be below
normal.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Little change to the expected pattern in the extended. Upr trof will
remain over the area thru Fri. Cyclonic flow aloft will keep temps
blw average with chances for shwrs thru the period. Highs generally
in the 50s and lows in the 40s. The cold pool aloft will keep steep
lapse rates locked in and the area primed for convective pcpn,
particularly during the daytime hours. Any strong dpva could
help to enhance convection and produce some isold low topped
tstms, perhaps with some small hail. High pres then attempts to
build in from the west over the weekend as ridging builds over
the Midwest. This will result in lessening chances for shwrs,
and a warming trend. Portions of the area could hit the lower
70s by Sun.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Low pressure will approach today, moving over the terminals this
evening, and then pass to the north tonight.

IFR to LIFR will remain at the terminals through this evening,
with improvement from south to north aft 04-06Z, becoming VFR
late tonight.

Light rain will be moving in this morning, with periods of
moderate to locally heavy rainfall. Timing of isolated
thunderstorms for late this afternoon and into this evening
still looks reasonable, although may be trending to an hour or
two later.

Northeast to east winds increase a few more knots this morning,
and gradually become more east to southeast through the
afternoon, with gusts possible. Gust, 25-30kt, may be more
occasional at the onset. Winds start to veer towards the W/SW
late aft 04-06Z. Gusty WSW flow on Mon.

The latest modeling indicates winds aloft in the 35-45kt range, so
LLWS is very marginal and has been removed from most of the TAFs.

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

High confidence of IFR or less through much of the TAF period.
Occasional wind gusts today may be higher than forecast.

Timing/coverage of tstms this aftn and eve remains uncertain.

The afternoon haze forecast for all NYC arpts today is MODERATE
(YELLOW).

OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...

Monday: VFR. Slight chance of afternoon rain showers with MVFR.
SW wind gusts near 20-25 kt.

Tuesday: VFR. Chance of afternoon rain showers with MVFR. SW wind
gusts 15-20kt.

Wednesday: VFR. Chance of afternoon rain showers with MVFR. W/NW
gusts 15-20kt.

Thursday: Mainly VFR. Chance of MVFR or lower in any rain showers.

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

&&

.MARINE...
Issued a dense fog advy for all but the harbor. Otherwise, the
fcst is on track.

SCA has been extended on the ocean waters as well as eastern LI
Sound. Even after winds subside a bit on Monday, seas will remain
elevated due to a lingering swell. Elevated seas probably last
through Tuesday night, so the SCA will likely need to be
extended in time. Wind gusts this afternoon into evening could
briefly reach gale force on the ocean. For the remaining waters,
winds increase as the pressure gradient tightens in response to
an approaching low pressure center. SCA has been posted here
from noon today through noon Monday.

Seas on the ocean could remain at sca lvls on Wed. Winds and seas on
all waters are expected to remain blw sca lvls Thu-Sat

&&

.HYDROLOGY...
-- Changed Discussion --
Rainfall of 1.5 to as much as locally 3.25 inches has fallen
through Saturday mid afternoon, and an additional 1 to 1.75,
with locally up to 2 inches across Connecticut, is possible from
through this evening. Minor nuisance flooding will be possible
once again this afternoon into this evening across poor
drainage and urban areas.

No hydrologic impacts are expected Monday through next weekend.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
A strong SE flow due to a deepening low pressure today may bring
evening high tide levels to minor flood benchmarks. The main concern
continues to be for the south shore Back Bays of southern Nassau and
southern Queens, western Great South Bay along southwest Suffolk,
and SW CT coast along the Western Long Island Sound. Astronomical
tides are low, so approximately 2 to 3 ft surge is needed to bring
water levels to minor flooding at these locations this evening.

A coastal flood statement remains in effect for southern Nassau,
southern Queens, southwest Suffolk, and coastal Fairfield as a
consensus of the guidance brings water levels to just touching minor
flooding benchmarks. A few of the more vulnerable locations could
see a few tenths above minor, but widespread minor flooding is not
expected at this time. Elsewhere, water levels should remain below
minor flooding during the evening high tide.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...Flood Watch through this evening for NYZ067-069.
NJ...Flood Watch through this evening for NJZ002-004-006-103>108.
MARINE...Dense Fog Advisory until 11 AM EDT this morning for ANZ331-332-
     335-340-345-350-353-355.
     Small Craft Advisory until noon EDT Monday for ANZ331-335-338-
     340-345.
     Small Craft Advisory until 6 PM EDT Monday for ANZ332-350-353-
     355.
-- End Changed Discussion --

&&

$$
SYNOPSIS...12/JC
NEAR TERM...JC/MW
SHORT TERM...JC/DS
LONG TERM...12
AVIATION...12/MET
MARINE...12/JC
HYDROLOGY...12/JC
TIDES/COASTAL FLOODING...