911
FXUS61 KOKX 201522
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1122 AM EDT Sat Jul 20 2024

.SYNOPSIS...
High pressure moves offshore today, with a surface trough lingering
over the area through the weekend. A weak cold front approaches from
the north on Sunday and likely dissipates before reaching the area.
A wave of low pressure passes to the south Monday night into
Tuesday. A stationary boundary will then be over the region the rest
of Tuesday into much of Wednesday. The front may lift north
temporarily late Wednesday into Thursday before sagging south and
pushing through as a cold front early on Friday. Weak high pressure
should return late Friday into next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
High clouds associated with an approaching shortwave trough have
overspread the area producing mostly cloudy skies. Closest
showers were well to the west across NE PA. Latest CAMs continue
to support shower development to the north and west of NYC this
afternoon.

High pressure will be offshore today with a S/SW flow. The
airmass will gradually destabilize through this afternoon, but
mainly north and west of NYC. The CAMs continue to show
isolated to scattered convective activity north and west of NYC
in the afternoon and then spreading east through the evening
and overnight. Thinking much of this activity will just be
showers with model soundings not showing any CAPE above
-15C. The Lower Hudson Valley looks to be a bit more unstable
than the rest of the area, with a deeper CAPE profile, so have
kept mention of thunder there.

Highs will be just a few degrees warmer than Friday, with
dewpoints in the 60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The surface trough continues to linger on Sunday, becoming a bit
more pronounced, while the flow aloft becomes more zonal. A
weakening cold front also approaches from the north, but will
likely dissipate before reaching the area. Most CAMs are hinting
at some convective activity popping up around NYC and Long
Island, likely due to increased surface convergence between sea
breeze boundaries and the surface trough. Similar to today,
left out thunder due to lack of a deep CAPE profile. Only
expecting a slight chance of some pop up showers.

A wave of low pressure will pass to the south Monday night into
Tuesday and likely bring more widespread showers and
thunderstorms. Chances start Monday afternoon and ramp up into
Monday night.

Highs Sunday and Monday will be back in the upper 80s, with
dewpoints in the 60s to low 70s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A frontal boundary will lock up over the region Tuesday and likely
into much of Wednesday. This should lead to a rather warm and humid
period of unsettled weather. A series of shortwaves are suggested by
global NWP leading to an extended period of chance and embedded
likely PoPs Tuesday through Thursday night. The most favored time of
day will be the afternoon and evening as per any diurnally favored
convection. PWATs are likely going to run at or above the
climatological 90th percentile. Any embedded thunderstorm activity
will likely lead to intervals of moderate to locally heavy rainfall.
See the hydrology portion of the AFD for more information.

Weak high pressure likely returns for Friday and into next weekend.

Temperatures through the period are likely to be near to slightly
above normal, with more of a tendency for above normal temperatures
for the night time due to high humidity and a tendency for clouds.
Cloud cover should preclude the need for any heat headlines during
this time frame. However, if the frontal boundary gets further north
and the region gets more clearly in the warm sector for any length
of time then heat headlines would be a possibility Wednesday into
Thursday.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
High pressure remains near the today. A surface trough will
linger nearby this afternoon into Saturday night.

VFR prevails. Slight chance of an afternoon / early evening shower N
and W of the NYC metro terminals. Will include a TEMPO at KSWF,
otherwise, confidence remains too low at the other terminals to
include any precip at this time.

Light WSW winds this morning, with the winds increasing mainly 7-10
kt this afternoon out of the SW. Sea breeze of 10-13 kt possible at
southern coastal terminals like KJFK and KISP. Variable to light WSW
winds return late this evening and overnight.

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

No unscheduled amendments are expected.

OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...

Sunday: Mainly VFR, brief MVFR possible in showers.

Monday: VFR. Potential MVFR for PM/Night in SHRA.

Tuesday and Wednesday: Periods of MVFR or lower likely with
SHRA/TSRA.


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

&&

.MARINE...
With a weak pressure gradient over the area, winds and waves will
remain below Small Craft Advisory criteria. The stretch of 2 ft
ocean seas is likely to continue through Tuesday night. A S-SW
flow may increase towards Wednesday with marginal small craft
conditions becoming possible by Wednesday night.

&&

.HYDROLOGY...
There are no hydrologic concerns through early next week.

The region will be in a humid and unsettled pattern towards mid week
with anomalously high PWATs. Therefore at this time there appears to
be at least a limited risk of localized flash flooding from any
thunderstorms that produce heavy rain. It remains too soon to lock
down any details around hydrologic related impacts for the Tuesday
through Thursday time frame. ML based progs are indicative of the
potential for a marginal to slight risk of excessive rainfall.

&&

.TIDES/COASTAL FLOODING...
Today, a moderate rip current risk is forecast for the ocean
beaches, with surf heights 2-3 ft and an onshore flow increasing to
10-15 kt in the afternoon. The moderate risk continues on Sunday
with similar conditions.

Minor coastal flood benchmarks may be approached along the western
south shore bays of Nassau and Queens for the Monday and Tuesday
night high tide cycles. There remains a good deal of uncertainty
around this, thus trends in the water level forecast will need to be
monitored for these locations.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JE/JT
NEAR TERM...JT/DW
SHORT TERM...JT
LONG TERM...JE
AVIATION...BC/JE
MARINE...JE/JT
HYDROLOGY...JE/JT
TIDES/COASTAL FLOODING...