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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 230330
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1130 PM EDT Wed Mar 22 2023

.SYNOPSIS...
-- Changed Discussion --
Low pressure north of the Great Lakes tonight will track across
eastern Canada through Thursday, sending a weak warm front or
surface trough across the area overnight, followed by a cold
frontal passage Thursday night. The cold front stalls to our
south on Friday as high pressure briefly noses down from eastern
Canada. A warm front lifts towards the area on Saturday. Low
pressure developing along the warm front moves across Saturday
night. High pressure then builds in from the north and west for
Sunday into Monday. High pressure departs Monday night. Low
pressure develops and approaches the area towards the middle of
next week.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
Minor adjustments made this update to account for latest
observations and trends. Temperatures a bit warmer than
forecast, especially over the metro area.

An area of low pressure along with a an upper trough across
southeast Canada will start to drag a cold front towards the
region overnight. This front will still remain well to our west
tonight with warm advection the main mechanism for increasing
moisture.

The models have been hinting as a surge of low level moisture
across eastern Long Island and southeast CT this evening into
tonight. A general consensus of the guidance indicates that the
bulk of any showers with this moisture surge will remain east of
the area. However, an isolated shower cannot be completely
ruled out over the east end of Long Island and in New London
County CT. Some of the light QPF on the models may be more of an
indication of some low stratus development rather than
measurable precipitation.

Otherwise, the bulk of the dynamics with the aforementioned
low will be located well to our north and west tonight. The
flow aloft will generally be westerly, but there could be some
subtle shortwaves in the flow along with warm advection that
could generate a few showers early Thursday morning, mainly
across the western half of the area. Any of this activity looks
to be light.

Lows tonight will be above normal in the 40s across the area,
possibly even around 50 for the NYC metro.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Low pressure will continue working its way across southeast
Canada on Thursday, slowly dragging a cold front through the
region by Thursday night. The flow in the middle and upper
levels continues to be zonal with the bulk of the dynamics
remaining well north of the area. This creates a challenge in
trying to time any weak disturbance or brief area of enhanced
lift ahead of the front. The 12z CAMS disagree on timing and
location of showers. The 12z global models are in a bit better
agreement overall with an initial wave of showers weakening in
the morning with little in the way of activity the rest of the
morning into the afternoon. There may be an increase in shower
coverage late in the day and evening as the actual cold front
moves across the region. Based on these uncertainties and low
forecast confidence, have capped PoPs off at 50 percent. There
may be a period where measurable rain becomes more likely, but
felt it is not clear at this time when exactly this will occur.
Any showers that do occur will be light and total amounts should
remain around one tenth of an inch or less.

The front moves south of the area Thursday night. Probabilities
of showers drop off through the evening with just a lingering
slight chance near the coast early Friday morning. The bulk of
the guidance shifts the axis of moisture well south of the area
overnight, so chances are increasing for completely dry
conditions returning.

Temperatures continue above normal on Thursday despite cloud
cover and potential showers. Highs look to reach the middle and
upper 50s for most with low 60s possible in the NYC/NJ metro.
Lows Thursday night continue above normal in the 40s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Mainly dry conditions for much of the area on Friday with
frontal rain staying south of the region. Forecast highs are
mainly in the lower 50s with decreasing NW winds. Northeast NJ
and parts of NYC may see some light rain as they will be closer
to the frontal boundary but chances for rain are less than 30
percent. The front and associated rain approach Friday night,
eventually getting close enough to warrant elevated chances for
rain overnight Friday night.

For interior locations and especially NW Orange County NY,
temperatures and dewpoints are cold enough to allow for the
precipitation to be a mix of rain and snow. For NW Orange
County, particularly higher elevations, precipitation type
could be mostly snow where temperatures are forecast to be near
freezing. For this location in NW Orange County, some light snow
accumulations of less than 1 inch are forecast. Otherwise, no
measurable snow accumulations expected for other interior
locations with temperatures more in the mid 30s. Temperatures
will be in the upper 30s to lower 40s along the coastal areas,
allowing for plain rain there.

The warm front slows down with eventual low pressure development
along it to the south and west of the area on Saturday. Rain
chances will be highest during the day Saturday. This will keep
temperatures on the cooler side despite some low level warm air
advection increasing in the afternoon towards the evening.
Also, surface winds will be easterly and gusty. Forecast highs
are in the 40 to 50 degree range for most locations.

The weather prediction models convey the low to move across
Saturday night mainly in the first half and then moving farther
offshore late Saturday night. Rain remains forecast until late
Saturday night.

Drier air advects in on an increasing westerly flow that will
be gusty late Saturday night and into the very early morning
hours of Sunday. Expecting lows to have less vast of a spatial
spread as a result, mainly in the upper 30s to lower 40s.

High pressure builds in from the north Sunday into Monday and
then shifts offshore by Monday night. Dry conditions are
expected to continue Sunday into Monday but rain could return
for Monday night. A developing low pressure area to the south
and west approaches the area and the forecast will have a slight
chance for rain Monday afternoon, increasing to a chance of
rain Monday night.

The forecast retains chances of rain Tuesday and into early
Tuesday night with lowering POPs going into the middle of next
week. There could be some wintry precipitation with rain and
snow across some of the interior at times with this event,
Monday night as well as Tuesday night with colder temperatures
forecast. However, uncertainty in the forecast is greater for
this timeframe with low confidence in the forecast. Models have
varied in their depiction of the position, strength and speed of
low pressure offshore largely apparent in the Tuesday night and
Wednesday morning runs of the GFS, ECMWF and Canadian weather
prediction models.

Looking at the long term and thunderstorm potential, slight
chance thunderstorms mainly Saturday afternoon into the first
half of Saturday night, mainly across the ocean zones and
coastal areas. Model Showalter indices are more negative across
the ocean and approach zero farther north. This is indicating
some elevated instability across the ocean that will decrease
farther north.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Low pressure north of the Great Lakes tonight will track across
eastern Canada through Thursday, sending a weak warm front or
surface trough across the area overnight, followed by a cold
frontal passage Thursday night.

Much of the guidance is supporting a period of IFR ceilings
developing to the south this evening and working north across
the terminals, mainly from a KJFK to KHPN line and points east.
As winds gradually veer to the SSW the second half of the
night, any IFR ceilings at the NYC terminals are likely improve
to VFR for a time, but improvement is expected to be slower for
the eastern terminals (KISP,KBDR, KGON). Even KHPN may hold on
a bit longer due to the weak SW flow having a difficult time
scouring out the low-level moisture. An additional shot of warm
advection and showers moving into the area from late Thursday
morning into the afternoon will likely bring MVFR ceilings to
all terminals with possible IFR at the eastern terminals,
especially at KISP and KGON. Improvement to VFR is expected
Thursday evening with an approach of a cold front. The cold
front is likely to pass through the terminals Thursday evening,
from around 01-02Z at KSWF, and around 04-06Z at the coastal
terminals.

S/SE winds will diminish to less than 10 kt and then gradually
veer to the SSW overnight, increasing to 10 to 15 kt by around
15Z. A few gusts up to 20 kt possible THursday afternoon. Winds
will continue to gradually veer through the day, becoming more
WSW toward 00Z Friday.


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

Amendments are likely for the timing of changing flight
categories overnight into Thursday. IFR ceilings will be in
close proximity overnight and may stay just east or possibly
even get into KEWR and KTEB for a time. Gusts on Thursday look
to be more occasional at this time versus frequent.

 ...OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...

Thursday Night: Chance of MVFR in SHRA first half of night,
then VFR. NW G15-20kt following cold frontal passage.

Friday: Mainly VFR.

Saturday: IFR possible in rain. E/SE winds G25-30kt, becoming NW
after midnight.

Sunday: Becoming VFR. W winds G25-30kt.

Monday: Mainly VFR.

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

&&

.MARINE...
Conditions on the waters will remain below SCA levels through
tonight.

The flow increases ahead of a cold front on Thursday with gusts
on the ocean, especially east of Fire Island Inlet reaching
marginal SCA levels. At the same time, seas will build to 5 to 7
ft through Thursday evening. Winds will weaken Thursday night,
but the ocean seas will likely remain elevated above 5 ft.
SCA is in effect on the ocean from Thursday afternoon through
Thursday night. Conditions on the non-ocean waters will remain
below SCA levels through Thursday night.

SCA conditions forecast on the ocean for Friday and Friday night
with below SCA on the non-ocean waters. The weekend features
mainly SCA conditions forecast on all the waters with potential
for some gales on the ocean and maybe even the eastern non-
ocean waters Saturday afternoon into Saturday night. Mainly
below SCA conditions forecast for Monday and Monday night next
week.

&&

.HYDROLOGY...
No hydrologic concerns anticipated through the middle of next
week. Rain forecast Friday night into Saturday is only around
0.5 inches with locally higher amounts possible.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from noon Thursday to 6 AM EDT Friday for
     ANZ350-353.
     Small Craft Advisory from noon Thursday to 2 AM EDT Friday for
     ANZ355.

&&

$$

SYNOPSIS...JM/DS
NEAR TERM...JM/DS
SHORT TERM...DS
LONG TERM...JM
AVIATION...DW
MARINE...JM/DS
HYDROLOGY...JM/DS