-- Discussion containing changed information from previous version are highlighted. --
874
FXUS61 KOKX 202048
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
448 PM EDT Thu Jun 20 2024

.SYNOPSIS...
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High pressure over the western Atlantic will remain in control
through late week. A cold front sliding down from the north
Friday into Friday night will lift to the north on Saturday and
remain to the north on Sunday. A cold front will approach Sunday
night and move through on Monday. High pressure will build in
for Tuesday. A warm front will lift north Tuesday night, with
another cold front moving through Wednesday night.
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&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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Seeing only some sct high clouds over the area and a few Cu over
inland sections. Pre-frontal trough with moisture convergence
may still help spark some showers/tstms across the northern
zones. Any storms could produce a strong wind gust or small
hail, but with weak shear, the threat of severe thresholds being
met will be limited to just off to our north, but not
completely out of the question over here. This agrees well with
SPC marginal risk still skirting our northern zones.

Following and afternoon where Central Park hit 90 degrees for
the first time this year, temps tonight will fall only to the
mid 70s in most of the city, with upper 60s/lower 70s elsewhere,
and mid 60s across normally cooler portions of eastern Long
Island. It will also be muggy inland where dewpoints will be
closer to 70.
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&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
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** Key Points **

* Heat advisories expanded to cover NYC, S
  Westchester/Fairfield and interior SE CT through Saturday

* Gusty thunderstorms possible on Friday especially inland

Have bumped up high temperatures for both Fri and Saturday based
on today`s obs and recent performance of GFS/ECMWF MOS
guidance. Based on this, temps across most of NE NJ should reach
the mid/upper 90s, with lower 90s across the Hudson Valley and
parts of interior S CT, also possibly the north shore of
Nassau/Suffolk on Long Island, and 80s elsewhere. Dewpoints
should mix out to the mid 60s from NYC north/west, but low
level moisture more likely to pool inland closer to the
approaching cold front and across most of southern CT, with
dewpoints closer to 70. This yields max heat index values just
over 100 in parts of urban NE NJ and in the valleys of Orange
County, and mid or upper 90s across a good deal of NYC and
remaining points north/west.

Tstms appear likely with the approaching front mainly across
the interior Fri afternoon, with that threat gradually expanding
S toward NYC metro and Long Island toward late day and early
evening. Steep low level lapse rates suggest a few storms could
produce strong winds, and SPC forecasts a marginal risk for the
interior.

This front should stall somewhere over the area late Fri night,
then lift back north on Sat. Sat could see the highest
temperatures for this heat event especially for NYC metro and NE
NJ as H8-10 thicknesses peak close to 1432m and H8 temps reach
20-21C per GFS/ECMWF, and temps at EWR/CDW reaching 100 (with
corresponding heat index close to 105) is not entirely out of
the question. Temps inland across S CT will not be as warm (near
90) but higher dewpoints there should still enable the heat
index to reach 95 especially farther away from the Sound.

With a sfc trough over the area and passing mid level shortwave
aloft there is once again chance for an afternoon or evening
tstm.

Lows both Fri/Sat night will range from the upper 60s to mid
70s, with mid 60s for Sat night across parts of SE CT and
eastern Long Island.
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&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
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** Key points **

* Above normal temperatures on Sunday transition to near or slightly
  above normal Monday through Wednesday. The end of the week cools
  down a bit.

* Unsettled Monday-Wednesday with multiple frontal systems affecting
  the area.

Upper level ridging just to our west starts out this period. The
ridge axis crosses Sunday night. Meanwhile at the surface, high
pressure over the Canadian maritimes retreats farther into the
northwestern Atlantic. Over the Great Lakes region, low pressure
strengthens as it heads into southeastern Canada. An old frontal
boundary attached to this parent low will move north as a warm
front.

Monday night should be mostly dry for the entire area, with just a
slight chance for showers  for the western third of the forecast
area as the warm front moves toward the region. Better chances for
precipitation on Monday as the warm front advances. The warm front
does not look like it moves through until the first half of Monday
night, which will then be followed quickly by the associated cold
front.

Some lingering showers for eastern areas Tuesday morning with
the departing front, and showers start to enter the forecast area
from the west with the next front in the afternoon. Otherwise,
mostly dry conditions are expected.

A cutoff low dives south from south Central Canada and affect the
may affect the area as early as Wednesday morning or as late as
Thursday given which model you look at. Followed NBM closely given
uncertainty during this time frame.

Temperatures on Monday will be at or just below normal thanks to
clouds and rain. Tuesday will be a few degrees above normal thanks
to more in the way of sun, with cooler temperatures for Wednesday
and Thursday.
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&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
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VFR as high pressure remains over the Western Atlantic through
the TAF period. A cold front slowly sags south towards the
region on Friday.

S-SSW winds 10-15 kt this afternoon. There could be some
occasional gusts 15-20 kt until early this evening. Winds will
weaken tonight and should back to the SW with outlying
terminals going light and variable. Winds increase Friday
morning and become S-SSW 10-15 kt by afternoon.

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

Occasional wind gusts to 15-20 kt possible until early this
evening.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...

Friday afternoon and night: Mainly VFR. Showers and
thunderstorms possible, mainly Lower Hudson Valley and
Southern CT. MVFR or IFR possible at KGON at night.

Saturday: Mainly VFR. Showers and thunderstorms possible in the
afternoon and evening.

Sunday: Mainly VFR. Showers and thunderstorms becoming likely
late day into the night. S-SW wind gusts 15-20 kt.

Monday: Mainly VFR. Chance of showers and thunderstorms.

Tuesday: VFR.

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

.MARINE...
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S winds could briefly gust to 25 kt into early this evening near
the NY Harbor entrance and the adjacent coastal waters into
early this evening. Otherwise, conditions will remain below
SCA levels through at least Saturday night.

Waves increase on the ocean waters to 5 ft on Sunday with an
increase in southerly flow and peak Sunday night to 5-7 ft.
Although seas diminish late Sunday night into early Monday
morning, a prolonged period of 4-6 ft seas are possible through
Monday night.

Gusts 25-30 kt across the ocean waters also look likely on
Sunday as a cold front approaches, as well as on the south shore
bays. Gusts up to 25 kt are also possible across the eastern
sound and Peconic and Gardiner`s Bays. While winds diminish for
non ocean waters for the first half of Sunday night, the ocean
waters look to continue to gust through Sunday night, and
possibly into Monday morning E of Moriches Inlet.
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&&

.HYDROLOGY...
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Showers and thunderstorms Friday afternoon through Saturday are
expected to produce an average of 1/2 to 1 inch to an inch of
rainfall well north of NYC, with 1/4 to 1/2 inch just north of
NYC, and generally 1/4 inch or less for NYC and Long Island.
Locally higher amts are possible if storms train along the
approaching front. There is therefore at least a marginal risk
for localized flash flooding during this period.

Another round of moderate to locally heavy rainfall will be
possible Sunday and into Monday morning. Uncertainty remains
high for hydrologic impacts for this time period.
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&&

.TIDES/COASTAL FLOODING...
There will be a moderate rip current risk for all ocean beaches
through Friday due to a S-SW wind wave.

&&

.CLIMATE...
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Here are current record high temperatures for today and Friday.

Thursday, June 20:

NYC: 98(1923)
LGA: 98(2012)
JFK: 94(2012)
EWR: 98(2012)
ISP: 93(1995)
BDR: 93(1953)

Friday, June 21:

NYC: 97(1988)
LGA: 98(2012)
JFK: 97(2012)
EWR: 100(1953)
ISP: 95(2012)
BDR: 96(2012)

Saturday, June 22:

NYC: 98(1988)
LGA: 99(1988)
JFK: 94(2012)
EWR: 101(1988)
ISP: 94(2012)
BDR: 93(1949)
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Heat Advisory until 6 PM EDT Saturday for CTZ005>008.
     Air Quality Alert until 11 PM EDT this evening for CTZ005>007-
     009-010.
     Air Quality Alert from 11 AM to 11 PM EDT Friday for
     CTZ009>012.
     Heat Advisory from noon Friday to 6 PM EDT Saturday for CTZ009.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ067>075-
     078>081-176>179.
     Air Quality Alert from 11 AM to 11 PM EDT Friday for
     NYZ067>075-078>081-176>179.
     Heat Advisory from noon Friday to 6 PM EDT Saturday for NYZ071.
     Heat Advisory until 8 PM EDT Saturday for NYZ067>070.
     Heat Advisory from noon Friday to 8 PM EDT Saturday for
     NYZ072>075-176-178.
NJ...Air Quality Alert until 11 PM EDT this evening for NJZ002-004-
     006-103>108.
     Heat Advisory until 10 PM EDT Saturday for NJZ002-004-006-
     103>108.
     Air Quality Alert from 11 AM Friday to 11 PM EDT Sunday for
     NJZ002-004-006-103>108.
MARINE...None.
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&&

$$

SYNOPSIS...BG/JP
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JP
AVIATION...DS
MARINE...BG/JP
HYDROLOGY...BG/JP
TIDES/COASTAL FLOODING...JP
CLIMATE...BG