FXUS61 KOKX 040746

Area Forecast Discussion
National Weather Service New York NY
346 AM EDT Sat Apr 4 2020

High pressure briefly builds over the region Saturday. A weak front
extending from southern Quebec into the Mid-Atlantic pushes through
New York state late Sunday. Dry conditions return Monday as second
high pressure system shifts over eastern Pennsylvania. Active
pattern returns mid week as a series of low pressure systems bring
increased rain chances Wednesday through Friday.



The mature low pressure system over the Atlantic drifts southeast
Saturday as a mid level ridge builds into central New York state.
Subsidence from the approaching ridge will dry out the mid and upper
atmosphere as RH values above 700 mb are below 25%. However enough
moisture in the low levels is expected to keep clouds overhead all
throughout the day. Despite the clouds little to no chance for rain
is forecast. Mild temperatures will be just around normal for this
time of year in the mid to upper 50s Saturday afternoon.

The aforementioned ridge axis stretching from Maine to West Virginia
moves off the east coast Saturday night into early Sunday morning.
Cloudiness should hold temperatures in the low 40s near the city
though some surrounding areas could see temperatures in the low 30s
prior to sunrise.


Sunday begins dry but some showers could be possible late in the
day towards the evening.Near the surface the high from the
ridge aloft shifts east of the area allowing for south wind in
return moisture into the area. Precipitable water values
increase from 0.50 to 0.80 inches. At the same time a shortwave
trough in southern Quebec and a weak frontal boundary extending
into the Mid-Atlantic pushes through the northeast states Sunday
evening. The front could provide the necessary lift needed for
isolated showers Sunday night. Though with the main area of
positive vorticity advection being off to the north only slight
chances for showers are forecast for now.

Following the frontal passage the atmospheric column dries
considerably as a surface high builds into central New York
state. Monday could be the first sunny day in over five days
with afternoon temperatures rising into the low 60s.


A quiet night Monday night into Tuesday morning with overnight
minimums falling into the 40s throughout the area as the
surface high once over central New York travels offshore. This
brings an end to the dry weather owing to a moisture return from
south winds.

Previous Long Term Discussion:

A complex frontal system extending east from low pressure
across the nation`s mid-section will approach into Tuesday.
There is some disagreement as to how the front will set up and
how close it actually gets to the region. Some global guidance
has enough of a confluence zone to the north to promote surface
high pressure building to our north, which could fend off the
warm front, at least at the surface for a time later Tuesday
into early Wednesday. The big question is when and where will
the warm front stall and become stationary. In any event, there
will be a good deal of clouds moving back into the region late
Monday night into Tuesday. The timing and the advancement east
of precip, which will be in the form of rain will prove to be
difficult due to the uncertainty that currently exists. After
collaboration with surrounding offices through it prudent to go
with slight chances POPs beginning early Tuesday morning and
through Tuesday night. Then raised to chance POPs on Wednesday
as potential surface low draws closer. Chose to continue with
low end chance POPs, mainly due to model uncertainty.

A strong shortwave associated with an intensifying upper level low
will then slide down out of the northwest territories of Canada for
later in the week. If this does indeed pan out then a cold pool
aloft will exist with a good deal of at least daytime heating
associated cloud cover into Friday. High pressure will then
gradually build in late in the week and into the start of the
following weekend with diminishing winds and dry weather expected.
Temperatures on average will remain several degrees above normal
through much of the long term, with temperatures trending cooler
during the second half of the period.



Low pressure well offshore drifts away from the Eastern Seaboard
through the day.

Mainly MVFR through this morning as ceilings lower to between 020-
030. Some improvement to low end VFR for the afternoon and early
evening. but MVFR may return overnight.

N-NE winds 10-15 kt through early this morning. then gradually
weakening through the remainder of the day. Frequent gusts around 25
kt remain possible at GON and possibly at ISP this morning. Wind
direction veers towards the E and then SE late.

.Saturday night... MVFR ceilings possible.
.Sunday...MVFR ceilings possible. Slight chance of a shower late in
the day.
.Monday-Tuesday...Mainly VFR. Slight chance of rain on Tuesday.
.Wednesday...MVFR or lower and rain possible.


Low pressure will continue moving away from the Eastern Seaboard
today. The pressure gradient over the waters will gradually relax
leading to a weakening of winds through the day. SCA gusts on the
Eastern Sound and Eastern LI Bays will end by noon and on the waters
east of Moriches Inlet this evening. However, seas will remain
elevated above 5 ft on the ocean waters due to lingering easterly
swells through Sunday. Therefore, the SCA has been extended through
22z Sunday on the ocean waters. Ocean seas should then fall below 5
ft Sunday night. Otherwise, a relaxed pressure gradient over the
waters through Tuesday will lead to sub-SCA conditions. An
approaching frontal system for the middle week could build seas and
increase wind gusts, but sub-SCA conditions should continue.


No hydrologic impacts are expected through the period.


Widespread minor coastal flooding is expected for LI shorelines,
NY/NJ Harbor and along Western LI Sound with this mornings high tide
cycle. Localized moderate flood impacts are possible for the south
shore back bays of LI.

Breaking waves of 4 to 8 ft continue this morning, gradually
subsiding through the day. Scattered areas of beach erosion and
localized washovers are possible during the times of high tide along
the Atlantic oceanfront and Orient Point with the highest threat
this morning.

Surge expected to gradually subside through the day. Localized minor
coastal flooding is possible along the south shore back bays of LI
with this evenings high tide and possible again during Sunday
mornings high tide. Coastal flood statements are possible.
Elsewhere, forecast tide levels fall below minor benchmarks for
Saturday evening and Sunday morning high tide.


NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is undergoing
its final stages of testing, and is operating at full power.


CT...Coastal Flood Advisory from 7 AM to 10 AM EDT this morning for
NY...Coastal Flood Advisory from 7 AM to 10 AM EDT this morning for
     Coastal Flood Advisory until 11 AM EDT this morning for NYZ080-
     Coastal Flood Advisory until 7 AM EDT this morning for NYZ074-
     Coastal Flood Advisory until 10 AM EDT this morning for NYZ079-
NJ...Coastal Flood Advisory until 7 AM EDT this morning for NJZ006-
MARINE...Small Craft Advisory until noon EDT today for ANZ330-340.
     Small Craft Advisory until 6 PM EDT Sunday for ANZ350-353-355.



NWS OKX Office Area Forecast Discussion