121
FXUS61 KOKX 210816
AFDOKX

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

.SYNOPSIS...
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.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front approaches today and stalls over or just north the
forecast area late in the day into night. SBCAPES across the
northern zones may increase to 1000-2000 J/kg. With lift from
approaching front and subtle shortwaves aloft, showers and sct TSTMs
will be likely across these zones in the afternoon and evening. PoPs
capped at chance across the rest 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. Thanks to the
extended period of dry weather we`ve been having, only a low chance
of flash flooding is anticipated for the Lower Hudson Valley and
southern CT as PWATS around 2 inches will be present with slow-
moving showers/TSTMs.

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.
So 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 upper
80s to lower 90s for most other areas as 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.

&&

.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 /08Z FRIDAY THROUGH TUESDAY/...
High pressure remains across the Western Atlantic. A cold front
slowly sags south late today into this evening.

Mainly VFR tonight and through much of the day Friday. Showers
and thunderstorms are then forecast to develop north of the area
terminals and move towards the coast. There are some questions
with respect to timing and coverage, however there is enough of
a threat to include PROB30s at all the terminals. Expect brief
periods of MVFR or even IFR conditions with any convection.

Winds remain light through sunrise then back to the SW.
Winds then increase and become S-SSW 10-15 kt by afternoon.
Winds gradually lighten again into Friday evening.

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

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

OUTLOOK FOR 06Z 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.
Ocean waves increase above 5 ft Saturday night and remain at
advisory levels through Sunday night as S-SW flow strengthens,
possibly with gusts around 30kt 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.

&&

.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...
Here are current record high temperatures for today and Saturday...


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 8 PM EDT Saturday for CTZ005>008.
     Heat Advisory from noon today to 8 PM EDT Sunday for CTZ009.
NY...Heat Advisory from noon today to 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.

&&

$$

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