540
FXUS61 KOKX 210139
AFDOKX

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

.SYNOPSIS...
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.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The forecast by and large remains on track with only minor
adjustments for this update over the next several hours. This
mainly had to do with clouds across mainly northern portions of
the area. With convection during the evening across MA and
interior New England have added some clouds across northern and
northeastern portions of the area. Some convective debris clouds
works in for a few hours, but no real sensible wx adjustments.
The outflow from the area of storms across MA has worked south
into Southern CT. Just a wind shift for a bit out of the north
with a minor drop in dew points. Otherwise dew points should
level off late in the overnight.

Following an afternoon where Central Park hit 90 degrees for
the first time this year, temps overnight will fall only to the
middle 70s in most of the NY and NE NJ metro, with upper
60s/lower 70s elsewhere, and middle 60s across normally cooler
portions of eastern Long Island. It will also be muggy across
much of the interior where dewpoints will be closer to 70.

&&

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

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Key points:

* Well above normal temperatures on Sunday transition to above
  normal Monday through Wednesday with temperatures closer to normal
  by the end of next week.

* Unsettled Sunday night through early Monday night with a cold
  front moving through. Unsettled conditions return towards the end
  of the week as another frontal system impacts the region.

The area will already be warm sectored Sunday morning with a warm
front draped across northern New England and a cold front across the
mid-West. The attendant low will be somewhere over the north
central/eastern Great Lakes region at the start of Sunday morning.
South to southwesterly flow and warm air advection noted in forecast
soundings will mean continued hot and humid conditions. Highs on
Sunday should top out in the 90s for areas north and west of NYC,
with the warmest readings across northeast NJ (middle 90s). Long
Island and coastal CT should see highs in the middle to upper 80s.
With dew points in the lower 70s and possibly even the middle 70s
(NBM is typically too low on dew points), maximum heat index values
could approach 105 for some areas across northeast NJ and the Lower
Hudson Valley, but right now, the most likely outcome is widespread
heat index values between 95 and 104, likely prompting the
continuation of heat headlines for areas that already have them in
effect.

A surface (thermal) trough may initiate some showers and
thunderstorm Sunday afternoon out ahead of the cold front across the
usual spots of northeast NJ, Lower Hudson Valley, and southwestern
CT, but don`t expect anything strong to severe with only weak lift
noted in forecast soundings associated with the trough.

Better chances for stronger storms will be associated with the
passage of the cold front Monday into early Monday night. However,
it`s too soon to tell how strong or where any storms will occur.

The cold front pushes off the East Coast for by the second half of
Monday night (though this may be +/- a few hours given model
differences) and high pressure builds in behind it, bringing an end
to uncomfortably humid conditions by late Monday night.

High pressure over the area for Tuesday will mean dry conditions. The
next chance for showers and thunderstorms will be late Wednesday
through Thursday with the approach of another cold front which at
this point looks to push through late Wednesday night into early
Thursday morning.

As for temperatures, slightly cooler for Monday and, with less humid
conditions. However, temperatures will still be above normal for
this time of year, with highs ranging from the middle 80s to lower
90s. With a warm front lifting north on Tuesday night, highs will be
warmer on Wednesday with more widespread 90s across the interior.
The cold frontal passage on Wednesday night will bring temperatures
down to more seasonal levels on Thursday.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
High pressure draped across the Western Atlantic and stretching into
the Mid Atlantic states remains in control for tonight into most of
Friday. A cold front slowly sags south late Friday into Friday
evening.

Mainly VFR tonight and through the day Friday. Pockets of brief MVFR
or IFR possible in showers and t-storms, mainly for northern most
terminals late Friday.

Some lingering occasional gusts 15-20 kt through 02z for KJFK. Winds
weaken overnight 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. Winds gradually lighten again into Friday
evening.

A few showers and t-storms begin to pop up further north late Friday
afternoon / evening and could impact some of the northern most
terminals. Brief MVFR and IFR conditions are possible. This has been
handled by PROB30 groups for KSWF, KHPN, KTEB, KBDR, and KGON
towards 21-22 Friday.

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

Occasional wind gusts to 15-20kt possible until 2z this evening for
KJFK. Any showers and t-storms late Friday could begin as early 20z
for KTEB.

OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...

Friday night: Mainly VFR. Showers and thunderstorms with MVFR or IFR
possible for mainly the Lower Hudson Valley and Southern CT.

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

&&

.MARINE...
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 to 7 ft. Although seas diminish a bit late Sunday night
into early Monday morning, a prolonged period of 4 to 6 ft are
possible Sunday night through Monday night. 25 to 30 kt gusts
across the ocean waters also look likely on Sunday as the cold
front approaches, as well as the south shore bays. 25 kt gusts
are 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, ocean waters look to continue to gust
through Sunday night, and possibly into Monday morning for the
eastern ocean zone.

Sub small craft conditions are likely to return on the ocean for
late Monday night into Tuesday.

&&

.HYDROLOGY...
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.

&&

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

&&

.CLIMATE...
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)

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 6 PM EDT Saturday for CTZ005>008.
     Heat Advisory from noon Friday to 6 PM EDT Saturday for CTZ009.
NY...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...Heat Advisory until 10 PM EDT Saturday for NJZ002-004-006-
     103>108.
MARINE...None.

&&

$$

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