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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 172358
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
758 PM EDT Wed Apr 17 2024

.SYNOPSIS...
A slow moving warm front approaches from the southwest and
moves through the area into Thursday. High pressure briefly
builds in for Thursday night into Friday before a cold front
passes through Friday night into Saturday morning. High pressure
then follows from Saturday afternoon through early next week. A
weak frontal system will impact the region mid week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Made minor adjustments to the probabilities this evening, and
with little to no CAPE or instability across the region into
early this evening have removed mention of thunder.

A high amplitude upper level ridge over southeastern Canada and
western New England will start to deamplify over the Mid
Atlantic this evening. As this occurs, a weakening stacked low
over the Great Lakes region will eventually lift a surface warm
front associated with this low will approach from the southwest
today.

The warm front will lead to isentropic lift in association with
overrunning moisture with rain showers across the region this
evening. Instability will continue to be the challenge with the
overall thunder potential but given that there has been some
lightning upstream the forecast now includes a slight chance of
some embedded thunderstorms later this evening. Confidence is
low (15%) on the likelihood of widespread mention of thunder
especially with a modest low level inversion keeping much of the
area stable. The 12z suite of CAMs still indicated the
potential for some short lived embedded heavier showers moving
through southwestern portions of the forecast area overnight
tonight within the New York City metro area.

During the overnight expect the shower coverage to increase
although decrease in intensity. As the WAA lift decreases,
showers will transition from potentially heavy at times to more
of a steady light rain.

Temperatures are expected to be near normal for this time of year.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Shower coverage looks to lower Thursday as isentropic lift
weakens over the area and high pressure building in from the
northeast brings in a cooler and drier air mass in the lower
levels.

The high building in with the weak low to our south will mean a
strengthening easterly flow develops across the area that
starts to increase late tonight. It does not look to be overly
windy, with sustained winds of 15 to 20 mph and gusts to 25 mph
by Thursday morning. Winds start to decrease Thursday afternoon
as the high continues to nose into the region, with the weak low
well out to sea by this point.

The easterly flow will also mean cooler than normal temperatures for
Thursday, with highs only in the upper 40s to lower 50s.

Mainly dry conditions from Thursday night (except perhaps some
lingering showers for eastern areas) through Friday morning with
high pressure over the region. The chances for showers increase
Friday afternoon and Friday night as the associated cold front
approaches and begins to move through late Friday night.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Little change in the long term and stuck fairly close to the
previous forecast/NBM.

A cold front approaches and passes through Friday night into
Saturday morning. Moisture will deepen along with a chance of
showers with its passage. High pressure then builds in behind
the front with dry weather for Saturday afternoon. The high will
continue to build into the region through the rest of the
weekend and remain in control of the weather through Monday.
High temperatures near normal on Saturday, but cooling off
slightly for Sunday. Temperatures rebound a few degrees on
Monday.

A 500mb trough then shifts through the Great Lakes on Tuesday
with an associated weak surface low and cold front. It appears
that we should by dry through the day, but cannot rule out a
shower for western zones by the end of the day. Rain chances
increase Tuesday night into Wednesday. Temperatures remain in
the lower and middle 60s.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Persistent pattern during the TAF period with low pressure and
a warm front staying south and west of the region with high
pressure to the northeast of the region.

Rain showers intermittent this evening will eventually become
more steady late tonight. The rain could be more moderate to
heavy late tonight and there also could be an isolated embedded
thunderstorm. Conditions becoming more MVFR this evening with
lowering expected to IFR late this evening into overnight.

Rain showers still expected for early Thursday but will become
more intermittent with rain not as likely Thursday afternoon but
there will still be a chance. Mainly IFR conditions are
expected.

The IFR will be mainly for ceilings with visibilities expected
to be MVFR to VFR within the TAF period.

Wind direction will be SE to E tonight and then more E to ENE
Thursday. Wind speeds will be near 10 kt tonight and then
increase Thursday to near 12-15 kt with gusts mainly in the
20-25 kt range. KSWF expected to have lower winds near 10 kts or
less without gusts during the TAF period.

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

Timing of IFR start and end time could be a few hours off from
TAF. There could be fluctuation between MVFR and IFR late
tonight into Thursday.


OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...

Thu night: Showers end with slowly improving conditions
Thursday night. MVFR conditions with a chance of IFR. E-ENE wind
gusts 15-20 kt in evening will diminish overnight.

Fri: VFR early, then MVFR afternoon and at night with a chance
of showers.

Sat: MVFR with showers ending in the early morning, becoming
VFR. W-WNW wind gusts 15-20 kt.

Sun through Mon: VFR.

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

&&

.MARINE...
No changes to the winds and seas at this time.

Winds and seas remain below SCA criteria through early evening.
However, easterly winds will increase tonight as strengthening
high pressure builds in, and by late tonight will likely reach
25 kt on the ocean waters and the entrance to the harbor. A few
hours later, all waters will see SCA wind gusts. A SCA is in
effect for all waters from late tonight through the day on
Thursday.

Winds gusts diminish Thursday night as the high continues to
build in over the area. Non ocean waters will likely drop below
25 kt early Thursday night. The ocean waters will likely have
SCA gusts hang on for the first few hours of Thursday night
before they also come down below 25 kt.

Seas build to 4 to 7 ft on the ocean by Thursday morning into
the afternoon, diminishing thereafter. However, they remain
above or right around 5 ft Thursday night, so an extension to
the SCA over the ocean may be needed for Thursday night and
perhaps into Friday with a persistent, though slowly weakening
easterly flow. Waves finally drop below 5 ft on the ocean by
Friday night.

High pressure building over the area waters Saturday through the
first part of next week should keep conditions sub-advisory waters
through at least Tuesday night. Conditions may build back to SCA
levels for Wednesday with the next low pressure and associated cold
front to approach.

&&

.HYDROLOGY...
There is the potential for 0.25" to 0.75" of rainfall through
Thursday afternoon. Although a brief heavy shower is possible,
no hydrologic impacts are expected with this event and
thereafter through the first half of next week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Thursday for ANZ331-
     332-335-340-345.
     Small Craft Advisory from 2 AM to 6 PM EDT Thursday for ANZ338-
     350-353-355.

&&

$$

AVIATION...JM