000
FXUS61 KOKX 011959
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
359 PM EDT Mon May 1 2023

.SYNOPSIS...
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Low pressure lingers in the Northeast through mid to late week. High
pressure then gradually builds into the region from the Great Lakes
this weekend.
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&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Main upper level jet remains south of the region. Mid to upper
level lows remain north of the area. At the surface, a trough
moves across with areas of low pressure in the Great Lakes and
another low moving well offshore.

In terms of weather, there will be periodic forcing with the
synoptic pattern. Going into early this evening, some surface
based instability, potentially up to a few hundred J/kg of CAPE
north and west of NYC will help allow for scattered showers and
possibly an isolated thunderstorm. If any isolated thunderstorms
do form, they will have instability in the -10 to -20 degree C
area so some small hail will also be possible.

Later on tonight, instability lowers with the loss of diurnal
heating. However, while thunderstorms will no longer be
probable, an increase in positive vorticity advection aloft will
provide more forcing for more showers to develop.

With the abundance of clouds and winds staying up in the
boundary layer, lows tonight will be staying mainly in the 40s.
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&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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The synoptic pattern will not change much with mid and upper
levels lows staying northwest of the region. Main upper level
remains south of the area.

Positive vorticity advection aloft continues during the day
Tuesday with a main shortwave moving across. Showers likely much
of the area, mainly in the morning into early afternoon. SW
breezy winds expected. Overall, expecting temperatures to
average below normal for high temperatures. Forecast highs stay
in the mid to upper 50s.

For Tuesday evening, POPs lower with a lull in the rain shower
activity as the models convey the local area to be in between
shortwaves with some subsidence aloft.

With abundant clouds and another shortwave approaching late
Tuesday night as well as light SW winds, not expecting low
temperatures to drop too much. Rain shower chances return for
late Tuesday night, mainly north and west of NYC with slight
chance elsewhere. Forecast lows are mainly in the low to mid
40s with some upper 30s for most interior parts of the region.
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&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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Continued unsettled weather to start the long term as the stubborn
upper low drifts overhead on Wednesday. The cold pool aloft and
associated steep lapse rates should be able to generate a fair
amount of cloud cover and scattered shower activity across the
region.

Model soundings indicate the presence of weak surface-based CAPE, a
hundred joules or two, which may allow for a couple of rumbles of
thunder and even some small hail. Confidence in coverage however
remains too low to include an explicit mention in the forecast at
this time, but not entirely out of the question.

W/SW flow on Wednesday veers northerly as the surface low slips
offshore, and this flow largely continues into the weekend. Coastal
sea breezes, especially Friday, will be the exception to this. The
upper low moves offshore Thursday, but troughing and low heights
linger. While probabilities are lower, a few showers are expected
Thu/Fri, especially in the afternoon, as the troughing is slow to
shift east. Overall, QPF will be light between the three days,
largely between a tenth and a quarter of an inch.

Surface high pressure attempts to build in from the Great Lakes over
the weekend as the trough shifts offshore and ridging develops over
the Midwest. This should result in drier conditions, and a warming
trend. So while highs remain stuck in the low-to-mid 50s on
Wednesday, or about 10-15 degrees below normal for early May, this
nudges upwards to around 60 on Thursday and Friday, into the 60s
Saturday, and into the 70s by Sunday. The adventurous should use
caution if tempted to hop in the ocean or sound for a swim this
weekend, water temperatures remain in the lower 50s, making those
who do susceptible to cold water shock. With subtle local
adjustments, national blended guidance was largely followed for this
update.
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&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
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A broad area of low pressure remains over the region through Tuesday.

VFR with scattered showers into tonight with no impacts to flight
categories. Showers become more numerous Tuesday morning.

Gusty WSW winds continue into early this evening, and then diminish
with the gusts ending. At a few locations gusts may be more
occasional. Gusty SW winds likely develop Tuesday morning, however,
gusts will be more in the 20-25kt range.

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

End time of frequent gusts may be off by 1-2 hours.

OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...

Tuesday: VFR. Showers likely. Low chance of MVFR. SW gusts 20-25 kt.

Wednesday - Thursday: Mainly VFR. Chance of showers and MVFR at
times.

Friday: VFR in the morning. Chance of afternoon showers with MVFR
possible.

Saturday: VFR.

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

.MARINE...
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SCA conditions remain on all waters until 8PM this evening.
Then, while wind gusts will be lowering, some residual higher
seas east of Connecticut River and Orient Point in Eastern Long
Island Sound will allow for SCA to linger until 10PM this
evening. Then, the non-ocean waters will be mostly below SCA
through the rest of the short term through Tuesday night
although in NY Harbor and Western Long Island Sound there will
be some marginal SCA gusts during the day Tuesday.

For the ocean, due to residual high seas, SCA remains through
the short term through Tuesday night, until 6AM Wednesday, east
of Fire Island Inlet. For ocean west of Fire Island Inlet, SCA
length a little less, until 2AM Wednesday, with sub-SCA
conditions thereafter for rest of Tuesday night.

Seas subside on Wednesday with conditions on all waters remaining
below SCA levels thru the weekend.
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&&

.HYDROLOGY...
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Residual minor flooding can be expected to continue through this
afternoon and potentially into this evening. Rain showers not
expected to amount to much through Tuesday night, with less than
a quarter of an inch on average.

Otherwise, no hydrological impacts are expected into early next
week.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ331-
     335-338-340-345.
     Small Craft Advisory until 10 PM EDT this evening for ANZ332.
     Small Craft Advisory until 6 AM EDT Wednesday for ANZ350-353.
     Small Craft Advisory until 2 AM EDT Wednesday for ANZ355.
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&&

$$
SYNOPSIS...JM/DR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DR
AVIATION...MET
MARINE...JM/DR
HYDROLOGY...JM/DR