discussion on 2023-05-19

000
FXUS61 KOKX 191758
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
158 PM EDT Fri May 19 2023

.SYNOPSIS...
High pressure moves further offshore today and tonight. An area of
low pressure develops just south of the area and moves through
Saturday, with a cold front quickly following into Saturday
evening. A weak cold front moves through on Sunday. High
pressure builds in for the beginning of next week and remains
in place through the middle of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --Adjusted high temperature forecast upward a little over most of
the area based on the latest observations, except for areas NW
of the city, where highs might fall short due to mostly cloudy
conditions. Cloud cover otherwise varies through the day with
mostly cirrus for the coast and cumulus inland. Dry weather
continues with high temperatures near normal from the mid 60s to
lower 70s.

For tonight moisture begins to move up along the coast, mainly
towards and after midnight. At the same time a cold front
transverses the Ohio Valley. Clouds will lower and thicken with
the area under a SE flow. Look for increasing lower level
moisture and clouds as per BUFKIT fx soundings. Towards and just
after midnight have PoPs going to slight chance, and towards
daybreak from 9 to 12z have chance PoPs. Followed closely the
RGEM, NAM 3K, HREF guidance for rainfall onset timing into early
Sat AM.-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
Beginning 12z Sat have the entire area increasing to Categorical
PoPs for much of the CWA. The most widespread period of steady rain
looks to be from 15z to 21z Sat with the arrival of best thermal
forcing via 35 kt 850 hPa jet. Have also shifted the axis of
rainfall a touch further west than previous package(s) which relied
more on the global guidance as higher res consensus is demonstrating
a bump up of QPF further west. There remains differences in the east
to west placement of moisture axis which of course impacts the
confidence on the higher QPF placement and coverage. Took more of a
compromise / blended approach with respect to rainfall amounts
through the day Sat. Have essentially settled in on 1 to 1.5 inches
of rain across the NE portions of the area before the activity
tapers and ends Sat night. Further west expect mainly a 0.5 to 1
inch rainfall. Stood fairly close to WPC Guidance. It should be
noted that the HREF is more aggressive with higher rainfall totals,
with it having over 2 inches across NE portions of the area. In any
event, rainfall has averaged well below normal this past two weeks,
thus it is a needed rainfall.

For Sat evening look for a cold front to move through which will
shift the winds to a drier westerly direction into Sat night. Look
for it to taper off after some showers occur along the cold frontal
boundary early on. Cannot rule out a rumble of thunder Sat.
night, but thunder probs remain relatively low at this time.
Any showers with the cold front should be relatively light as
the thermal forcing will have lifted well to the north and east
by this time. Otherwise gradual / partial clearing takes shape
on dry and cold air advection. A fair amount of clearing sets up
into early Sun AM. Lows will range in the 50s as the noticeably
drier push of air occurs late and dewpoints lower closer to
daybreak.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
A secondary and dissipating cold front or trough enters and attempts
to shift through during Sunday. Moisture is lacking by this time, so
dry weather expected. Temperatures aloft should rebound in the
afternoon, and with a westerly wind flow, high temperatures should
reach the 70s across the area, even at most coastal sections.

A surface ridge then slowly shifts through the Northeast and remains
in control of the weather through the middle of next week. Dry
weather expected through Thursday. High temperatures near normal on
Monday, then after a slight cool down on Tuesday, temperatures
slowly moderate for Wednesday and Thursday.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --High pressure east of Long Island continues to move east through
this evening. A weak wave of low pressure approaches from the
south and impacts the area Saturday.

VFR through late this evening at all terminals. MVFR ceilings
move in after 05Z Saturday and then drop to IFR around 09Z.
The best chance for high end LIFR cigs look to be between 12 and
18Z Saturday and have included this in a prevailing group. Cigs
then slowly improve thereafter, becoming IFR around 18Z and MVFR
around 22Z.

-SHRA could bring MVFR visby as early as 09z and then more
steady moderate rain is expected by 12z, with MVFR/IFR vsby.

A S/SE flow 10-15KT continues this afternoon. Gusts up to
around 20 kt likely, ending toward sunset, with winds shifting
more to the SE, then E toward daybreak Saturday. Winds remain E
through Saturday afternoon and then become more S at 18Z.


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

No unscheduled amendments are expected through the day today.

Gusts in the afternoon may be more occasional, and may end 1 to 2
hours earlier than is forecast.

Amendments are possible as cigs lower tonight. Lowering to IFR
may happen an hour or two earlier. Increasing back up to MVFR
Saturday afternoon may happen an hour or two later.


OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

Saturday Afternoon: IFR to LIFR with showers. Possibly
improving to MVFR west late in the day. An isolated TSTM
possible for eastern terminals, with a low chance for LLWS at 2
kft for these areas as well.

Sunday through Wednesday: VFR.

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

&&

.MARINE...
With high pressure moving further offshore today look for a
southerly flow to prevail, and more of a SE flow tonight. Some
gusts will likely approach 20 kts out on the western ocean and
some of the near shore waters this afternoon and early this
evening, but conditions fall short of small craft with respect
to winds and seas. For Friday night a SE flow prevails with 3 ft
ocean seas. During Saturday AM seas will climb to small craft
levels as seas get to 5 to 7 ft by afternoon and stay elevated
through a good portion of Sat night. The winds gusts to around
20 kt or thereabouts for the ocean and possibly the LI South
shore bays into the first half of Sat night, followed by
decreasing winds out of the west into early Sun morning.

4 to 6 ft waves slowly diminish Sunday with high pressure building
in, falling below SCA Sunday night. With high pressure in control
through the middle of the week, sub-SCA conditions are expected.

A high pressure ridge then slowly shifts through New England Monday
into Tuesday with E-NE winds 10-15 kt prevailing. An easterly swell
may however contribute to 5 ft seas at times on the ocean both
days.

&&

.HYDROLOGY...
Rain amounts from early Saturday morning through Saturday evening
have increased in the last couple of runs. QPF overall is
expected to be higher, especially across the eastern 2/3rds of
the Tri- State area from previous thinking. However, with the
dry antecedent conditions in the last couple of weeks, no
hydrologic impacts are anticipated at this time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 11 AM Saturday to 6 AM EDT Sunday
     for ANZ350-353.
     Small Craft Advisory from 11 AM Saturday to midnight EDT
     Saturday night for ANZ355.

&&

$$
SYNOPSIS...JE/JP
NEAR TERM...JC/JE
SHORT TERM...JE
LONG TERM...JP
AVIATION...JT
MARINE...JE/JP
HYDROLOGY...JE/JP