Area Forecast Discussion
Issued by NWS Upton, NY

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535
FXUS61 KOKX 211936
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
236 PM EST Thu Nov 21 2019

.SYNOPSIS...
High pressure builds into the region today before sliding offshore
tonight. A cold front then crosses the area on Friday, followed
briefly by high pressure early on Saturday. A progressive upper
level pattern continues through the weekend bringing increased
rain chances Saturday night into Sunday, and by the middle of
next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast generally remains on track. Adjusted temperatures
upward slightly with abundant sunshine observed amidst
subsidence from building deep layer ridging. A few high level
clouds may begin to move in from the west late well ahead of
the next approaching low pressure system.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
High clouds increase this evening as the 500 mb ridge axis gets east
of the area. Clouds will continue to lower through the late evening
with bases getting down to around 10 kft towards and just after
midnight. Slight chance POPs get introduced late tonight for
northwestern sections as a shortwave in the mid and upper
levels approaches from the west. With the shortwave at 700 mb,
700 mb RH levels do increase, but other levels remain fairly dry
late tonight so it appears that it will be difficult to get
much of anything down to the ground. It appears that it will be
a situation where light precip northwest of the area dries up as
it heads southeast into our region into early Friday morning.

During Friday morning northern branch energy dives southeast as
energy in the southern branch attempts to catch up with the base of
the progressing trough. It appears that the southern branch will not
phase with the northern branch with southern branch moisture and
energy remaining south of the area and getting off the Mid Atlantic
coast during the day on Friday. Therefore any meaningful
precipitation will remain south of the area. The cold front should
drive through the area towards mid day on Friday. By 20z or so the
trough axis will swing east of the area with gusty northwest winds
developing across the area. Both GFS and NAM soundings show mixing
not getting much above 5kft. Therefore wind gusts should be capped
at about 25 to 30 mph.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Following the cold front, an upper level ridge builds into the
Northeast late Friday night into Saturday as a drier and cooler
airmass work south into the Lower Hudson Valley. Temperatures
Saturday may only reach the mid 40s by the afternoon throughout the
region despite the relatively clear skies. Throughout the day a
trough axis extending south through northern Mississippi River
Valley shifts east deepening a low pressure system over Tennessee.
Locally the region begins to feel the effects from this system as a
cirrus shield enters the forecast area from the southwest late in
the afternoon spurred on by 120kt upper level jet max over Northern
Alabama.

Depending on the timing of this system our northern most counties
could see mixed precip and trace amounts of freezing rain with
the initial precipitation late in the evening and into the
overnight hours Saturday night into early Sunday morning. Model
soundings do show an slight warm layer aloft but refreeze by be
possible prior to rainfall reaching the surface. This is
strictly for our northwest most counties. Areas closer to the
NYC metro and Long Island show a mainly rain event. Rain lingers
through the day Sunday with breezy northwest winds following
the cold front.

The region sees mostly seasonal temperatures through the first half
of the week next week as another ridge axis pushes east through New
York State. Monday is slightly cooler with highs in the upper 40s
while Tuesday should be slightly warmer with highs in the low 50s.
Rain chances return mid week with the next system. Models are
indicating at Wednesday rain event though much uncertainty still
existing over the exact timing and location of driving system. This
will continue to be monitored as changes arise.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
High pressure remains south of the region through tonight. A
cold front approaches from the west on Friday, crossing the area
Friday afternoon.

Primarily VFR through the TAF period. A brief period of MVFR
ceilings in rain is possible on Friday with the frontal
passage, but the probability remains too low to include in the
TAFs at this time.

Winds will continue to back to the W and then SW into the
evening at speeds of 10 kt or less. Light S-SW flow this
tonight increases early Friday morning. Sustained winds 10-15
kt with gusts around 20-25 kt become likely at coastal terminals
around day break. Winds shift to the NW during the afternoon,
with continued gusts to 20-25 kt.

     NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.

KLGA TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.

KEWR TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.

KTEB TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.

KHPN TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.

KISP TAF Comments: Timing of wind shifts through this evening
may be off by 1-2 hours.


.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.Friday...Low chance of MVFR in rain showers, otherwise VFR. SW
winds around 15 kt shift to the NW with gusts 20-25 kt in the
afternoon and evening.
.Saturday...VFR.
.Saturday night...Becoming MVFR to IFR in rain. Wintry mix
possible at KSWF.
.Sunday...Rain with MVFR/IFR, ending during the afternoon.
NW winds gusting to around 20 kt in the afternoon.
.Sunday Night-Tuesday...VFR.

&&

.MARINE...
With high pressure building to the south of the coastal waters
today and a weakening pressure gradient winds will be lighter
and seas lower. Winds and seas will then build during Thursday
night on a southwest flow ahead of an approaching cold front.
Winds and seas increase to SCA levels for all coastal waters
early on Friday, with potential gale force gusts out on the
eastern two thirds of the ocean waters mainly during Friday
afternoon and Friday evening.

SCA conditions could linger into Saturday morning over the ocean
waters south of Long Island as northwest winds 18-23 kt with waves 4-
5 feet relax throughout the day. The next system late Sunday into
Monday could again bring increased waves 5-6 feet for the ocean
waters. These conditions subside by the daylight hours on Monday.

&&

.HYDROLOGY...
No hydrologic impacts are anticipated through the period.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is operating
at reduced power until further notice.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 5 AM Friday to midnight EST Friday
     night for ANZ335-338-355.
     Small Craft Advisory from 5 AM Friday to 5 AM EST Saturday for
     ANZ330-340-345.
     Gale Watch from late tonight through Friday evening for ANZ350-
     353.

&&

$$
SYNOPSIS...JE/DJ/16
NEAR TERM...MD/JE
SHORT TERM...JE
LONG TERM...DJ/16
AVIATION...FEB
MARINE...JE/DJ/16
HYDROLOGY...JE/DJ/16
EQUIPMENT...



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