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859
FXUS61 KOKX 211426
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1026 AM EDT Fri Jun 21 2024

.SYNOPSIS...
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A cold front approaches from the north today and stalls over or
just north of us this afternoon into tonight, slowly retreating
back north as a warm front this weekend. Another cold front
then approaches Sunday night and passes through during Monday.
High pressure returns for Tuesday with a warm front lifting
north through the region Tuesday night. Another cold front
approaches on Wednesday and passes through at night into
Thursday.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
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Forecast continues on track this morning.

A cold front over central New England sinks south towards the
region this aft/eve, stalling over or just north of the
forecast area late in the day into night. A weak outflow
boundary also lies across Southern CT this morning.

Marginal to moderate instability development likely in a weak
shear to the north of afternoon sea breeze boundaries this
afternoon. With trigger from subtle shortwaves aloft, and focus
along sea- breeze boundaries and outflow boundary, scattered
SHRA/TSTMs development likely this afternoon and evening across
LoHud and S CT. With westerly steering flow, and more stable
airmass along the coast, question on how far south this
convection sinks into NE NJ, NYC and LI. PoPs remain capped at
low chance across southern portions of the forecast area. Shear
remains weak and mid level lapse rates will be relatively
stable, but can`t rule out a strong to severe wind gust north of
the city, consistent with SPC`s marginal risk for severe
weather today. Only a low and isolated chance of flash flooding for
the Lower Hudson Valley and southern CT from slow
moving tstms in a 2" PWAT environment.

Surface dewpoints away from onshore wind influence probably have a
more difficult time mixing out during peak heating this afternoon as
compared to yesterday. This is due to higher progged dewpoints
through the boundary layer. This higher moisture content will also
lessen the efficiency of insolation for potential high temperatures.
With 850mb temps from around 17C across NE sections to 19C for
SW sections, highs in the mid 90s for a good portion of NE NJ
and NW NYC metro, with upper 80s to lower 90s for most other
areas. Immediate south-facing coasts end up mostly 80-85. Heat
advisories remain unchanged for this period, although it`s
possible that between today and yesterday, portions of Northern
Nassau and NW Suffolk county end up meeting the 2-day criteria.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The stalled front most likely starts out over the northern zones or
just north of us on Saturday before it retreats north as a warm
front. It may be slowed down or pushed back southward at times by
outflow of potential thunderstorms that may pop up in the afternoon
as MLCAPES for many inland spots rise above 1000 J/kg and some
guidance shows subtle low-mid level shortwaves traversing the area.
Shear will be a little stronger, so again at least a strong wind
gust could occur with any storms that develop. 850mb temps climb by
late in the day, ranging from around 18C across NE sections to 19-
20C for SW sections. Boundary layer moisture will probably again
make it difficult for surface dewpoints to mix out, but at the same
time work against ambient temperatures. Additionally, with more
morning cloud cover/higher afternoon convection potential for the
northern zones, and an earlier sea breeze for coastal areas, highs
for Saturday may be slightly cooler than today for most areas in
spite of warming temperatures aloft. The exception would be NE NJ
where there`s a better chance of more morning sunshine and lower
chances of afternoon convection. Expecting highs mainly in the mid
90s again for NE NJ. Heat advisories remain unchanged for Saturday,
however it looks like portions of the Lower Hudson Valley and most,
if not all of southern CT will fall short of 95 heat indices. Didn`t
want to cancel advisories, especially with at better chance of
reaching 95 on Sunday for most these areas.

For Sunday, a cold front approaches from the west, with a pre-
frontal trough possibly touching off showers and thunderstorms
starting mainly in the afternoon. Stronger lift arrives in the form
of the cold front and shortwave during Sunday night, thus higher
PoPs during this time frame. Shear will be stronger this time, and
initially, CAPES should be sufficient in the afternoon for strong to
severe thunderstorms. Too early to have confidence in how much
instability is still around by the time the shortwave and cold front
push through, so trends will need to be monitored. Flooding threat
will in part depends on what transpires today and tomorrow. For now,
still only anticipating at most a low risk of flash flooding.

Some disagreement among models regarding 850mb temps, but an average
appears to yield 19-20C for most of the area. Once again, boundary
layer moisture probably makes it difficult for surface dewpoints to
mix out, and work against potential ambient temperatures. Warmer
high temperatures versus Saturday across the board. Also, high
enough confidence to extend heat advisories through Sunday for
most of the zones that had been in advisory through Saturday.
The exceptions are Northern Middlesex and Northern New London
Counties were there`s high enough confidence that criteria will
fall short for both Saturday and Sunday, and after collaboration
with WFO ALY, have not extended the advisory for Northern Fairfield
and Northern New Haven Counties.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key points:

* Temperatures remain above normal Monday through Wednesday with
  temperatures closer to normal by the end of next week.

* Unsettled Monday with a cold front moving through.

* Another round of showers and thunderstorms Wednesday into Thursday
  with another cold front.


The cold front pushes across the region early Monday morning.
Chances for showers and thunderstorms can be expected with the
passage of the cold front.

High pressure builds into the area behind the cold front, bringing
an end to uncomfortably humid conditions. High pressure over the
area Tuesday will result in 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, with less humid
conditions. Temperatures however,  will still be remain 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 /14Z FRIDAY THROUGH TUESDAY/...
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High pressure remains across the Western Atlantic. A cold front
slowly moves south late today into this evening.

Mainly VFR today. Showers and thunderstorms are forecast to
develop north of area terminals 18-20z and drift south and east
toward the coast as they dissipate. The question is how much
coverage do we get down to coastal terminals. Opted to flip the
PROB30 to a TEMPO for TSRA at all terminals except KJFK and
KISP, which was switched to SHRA where confidence is lowest in
any thunderstorm persisting that far south.

Brief period of MVFR or even IFR conditions with any convection.
Depending on how much, if any, precipitation falls, some patchy
fog/stratus may develop tonight. Confidence too low to include
in the TAF at this time.

Winds back to the S or SSW and increase 10 to 15 kt by
afternoon. Occasional 20 kt gusts possible by late day. Winds
gradually lighten again this evening, with similar flow expected
to today expected on Saturday.

The afternoon KJFK, KLGA, and KEWR haze potential forecast is
YELLOW...which implies slant range visibility 4-6SM outside of
cloud.

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

Amendments possible for timing and coverage of showers and
thunderstorms late this afternoon/evening.

Occasional gusts up to 20 kt late this afternoon possible.

OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...

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,
mainly in the morning.

Tuesday: VFR.

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

&&

.MARINE...
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Conditions will remain below SCA levels through at least Saturday.
Marginal SCA conditions possible for ocean waters leading to NY
Harbor and surrounding near-shore waters with afternoon coastal
jet development and seas of 3 to 5ft.

Higher confidence in SCA over the ocean waters as seas increase
above 5 ft Saturday night and remain at advisory levels through
Sunday night as S-SW flow strengthens. Gusts around 30kt
possible Sunday into Sunday night. Some of the non-ocean waters
may see advisory conditions as well during Sunday into Sunday
night as gusts approach 25 kt.

Small craft conditions remain likely on the area waters Monday with
seas above 5 ft.  Conditions fall below small craft late Monday
night into Tuesday morning.
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&&

.HYDROLOGY...
Showers and thunderstorms this afternoon through tonight are
expected to produce an average of 1/2 to 1 inch to an inch of
rainfall well north of NYC, and up to a half inch possible elsewhere.
Only a low chance of localized flash flooding is possible for areas
well north of NYC.

Additional showers and thunderstorms will be possible both days this
weekend - moreso during Sunday/Sunday night. Uncertainty remains
somewhat high for hydrologic impacts for this time period as it will
in part depend on what occurs today/tonight. Therefore, only a low
chance at most for flash flooding is anticipated this weekend.

Another round of moderate to locally heavy rainfall will be possible
Monday. Again, 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...
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Here are current record high temperatures for today thru Sunday...


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)

Sunday, June 23

NYC: 96(1888)
LGA: 95(1965)
JFK: 94(2010)
EWR: 97(1965)
ISP: 91(1999)
BDR: 91(2010)
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Heat Advisory until 8 PM EDT Saturday for CTZ005>008.
     Heat Advisory until 8 PM EDT Sunday for CTZ009.
NY...Heat Advisory until 8 PM EDT Sunday for NYZ071>075-176-178.
     Heat Advisory until 8 PM EDT Sunday for NYZ067>070.
NJ...Heat Advisory until 8 PM EDT Sunday for NJZ002-004-006-103>108.
MARINE...None.
-- End Changed Discussion --

&&

$$

SYNOPSIS...BC/JC
NEAR TERM...JC/NV
SHORT TERM...JC
LONG TERM...BC
AVIATION...BC
MARINE...BC/JC
HYDROLOGY...BC/JC
TIDES/COASTAL FLOODING...
CLIMATE...