discussion on 2024-04-17

000
FXUS61 KOKX 170958
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
558 AM EDT Wed Apr 17 2024

.SYNOPSIS...
A slow moving warm front approaches from the southwest today
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 /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --The forecast is on track with only minor changes needed.
Previous discussion follows.

High amplitude upper level ridge over southeastern Canada and
western New England will shift east today and weaken on its southern
end. Meanwhile, a stacked low over the Great Lakes region will
weaken as it heads into the ridging over southeastern Canada. A
surface warm front associated with this low will approacher
from the southwest today. Finally, a weak surface low may
develop off the mid- Atlantic Coast and head east this morning.

Isentropic lift in association with overrunning moisture from the
warm front will increase today. Rain showers from will move in from
the west by the early this afternoon and spread eastward into the
evening. Conditions look rather stable at the surface and aloft
to preclude any mention of thunder, though some of the CAMs are
showing embedded heavier showers moving through southwestern
portions of the forecast area overnight tonight within the New
York City metro area. However, if they do occur, expect them to
be short lived.

Temperatures are expected to be near normal for this time of year.-- End Changed Discussion --

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Shower coverage looks to lower late tonight into 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. However, showers should still be pretty widespread
tonight, with POPs transitioning from definite to likely wording
across the forecast area. Coverage continues to lower for Thursday
with POPs transitioning from likely to a chance Thursday morning
into Thursday afternoon.

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 TUESDAY/...
An inverted trough extending north from low pressure to our south
will linger near the forecast area Thursday night through Friday.
Moisture will be shallow during this time, but there could be just
enough isentropic lift in the vicinity of the trough for some
drizzle. Cloudy otherwise, with high temperatures in the middle to
upper 50s on Friday.

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 and Monday.

A 500mb trough then shifts through the Great Lakes on Tuesday with
an associated weak surface low. 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.

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
High pressure over the terminals weakens today as a warm front
slowly approaches from the southwest.

VFR through most of the day. Showers/rain become likely around 22z,
however there is a chance that some light precip starts at early as
20z. Most of the precip though 00z should remain VFR, however can
not rule out a brief period of MVFR conditions with the rain. MVFR
conditions become more likely towards 00z, then dropping to IFR
around 02-04z as the light rain become more steady.

Winds will be light and variable early this morning. Winds increase
around daybreak with speeds between 08-12kt taking in more of an
easterly component. Wind direction will generally be between 080-120
for much of the TAF period.

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

Timing of the wind changes possible this morning depends on the how
quickly high pressure weakens and the speed of the warm front
approach. Timing of the onset of light rain and MVFR conditions late
Wednesday may be off by 1-2 hrs.

OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...

tonight through Thu night: IFR conditions and possibly LIFR at times
with showers Wednesday night through Thursday. Showers end with
slowly improving conditions Thursday night. Winds Thursday east
around 15kt with gusts 20-25kt, highest along the coast.

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

Sat: MVFR with showers ending in the morning, becoming VFR.

Sun: VFR.

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

.MARINE...
Winds and seas remain below SCA criteria today and for the first
part of tonight. 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 has been issued 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 from
late this afternoon through Thursday afternoon. Although a
brief heavy showers 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.

SYNOPSIS...BC/JP
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...BC
AVIATION...BC
MARINE...BC/JP
HYDROLOGY...BC/JP