000
FXUS61 KOKX 240746
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
346 AM EDT Sat Jul 24 2021

.SYNOPSIS...
High pressure will be in control today. A warm front approaches
tonight and passes through on Sunday, followed by a cold front
late Sunday night into Monday morning. Weak high pressure then
regains control through Tuesday. A series of frontal systems
will approach from the northwest Wednesday into Thursday,
possibly into Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Deep-layered ridging keeps us dry today with mostly sunny
conditions. Highs at or slightly below normal with dewpoints
around 60.

The ridge aloft flattens tonight and a surface warm front
approaches. Theta-e ridging and isentropic lift increase with
moisture, and at least scattered showers should be pushing through
some of the forecast area after midnight. Included the mention of an
isolated thunderstorm as there will be some elevated instability
with the best lift beginning to push through.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The warm front passes through during Sunday morning, ushering
scattered showers and isolated thunderstorms off to the east with
it. Mainly dry conditions follow for the rest of the day, however
CAPEs in the warm sector will be rising with a pre-frontal surface
trough potentially supplying a focus for afternoon convection. The
best combination of instability and lift will be over the NW half of
the forecast area, but will cap PoPs at chance as implied by CAMs
reflectivity. A trailing cold front then begins to moves through
during the overnight hours, keeping the shower/TSTM chance in the
forecast through the night. TSTMs could be strong to severe in the
afternoon and evening with the greatest threat of severe weather
being tied to wind gusts. Bulk shear will be in the range of 25-30kt
during this time, coinciding with the highest CAPEs and a fairly dry
sub-cloud layer.

For high temperatures, went close to NBM numbers. This could
potentially be underdone by a couple of degrees over western half of
the forecast area, but given the uncertainty of cloud cover here in
the afternoon, NBM was the best compromise - being on the warmer
side among model output.


The cold front sinks south through the area Monday morning with low
chances of a shower or thunderstorm for the southern half of the
area, then dry in the afternoon. 850mb temps rise to around 17C, and
with a westerly boundary layer wind flow, highs should reach the
upper 80s to lower 90s for most of the area. The boundary layer
winds and RH profile likely allow afternoon dewpoints to drop a few
degrees in most areas except LI and coastal CT. Max heat indices
therefore end up 90-95 for most areas. Dry weather then continues
for Monday night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
An amplifying heat ridge over the western states and a downstream
trough with its axis just to the east will be the main driving
factors for the long term weather.

The flow aloft becomes briefly zonal on Tuesday. At the surface the
forecast area will be between two cold fronts, one off shore and
another approaching from the northwest, with weak high pressure over
the region.

As the western ridge and trough to our NE both amplify mid to late
week, a series of northern stream disturbances should take aim at
the Northeast and Mid Atlantic. This could make for some interesting
severe weather in areas near the southern edge of the westerlies and
an associated NW-SE oriented quasi-stationary front that may set up
during this time. It is too early to know how the local area might
be affected, other than to forecast mainly diurnally driven
showers and thunderstorms Wednesday through Thursday.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
High pressure remains over the terminals through Saturday
morning, and then begins slowly sliding southeast into the
Atlantic Saturday afternoon into Saturday evening. A warm front
approaches from the west Saturday night.

VFR through the TAF period.

Light and variable winds for all terminals overnight. A
northeasterly flow Saturday morning transitions to
southeasterly by the early afternoon, then southwesterly in the
evening, with sea breeze enhancements likely.

Showers associated with the warm front will affect terminals
after 06Z Sunday.

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

No unscheduled amendments expected overnight.

.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.Saturday night...VFR. Chances for showers and MVFR increase
late at night.
.Sunday...MVFR or lower possible. Showers likely in the morning
with a slight chance of a thunderstorm. Chance of showers and
thunderstorms afternoon into the night.
.Monday...MVFR or lower possible with a chance of showers,
mainly in the morning. A slight chance of a thunderstorm.
.Tuesday...Mainly VFR.
.Wednesday...Chance of MVFR with a chance of showers and
thunderstorms.

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

&&

.MARINE...
Winds and seas are expected to remain below SCA criteria through
tonight with high pressure in control.

Sustained SW flow increasing to around 20 kt on the ocean waters
Sunday and Sunday evening should push ocean seas up to 5-6 ft. Gusts
around 25 kt expected here, and possibly on some of the other waters
as well during this time. Have enough confidence for a SCA on the
ocean, and will mention occasional gusts to 25 kt for some of the
other waters. A lingering swell then maintains SCA conds on the
ocean on Monday. Thereafter, winds and waves are expected to
remain below SCA criteria through the middle of next week.

&&

.HYDROLOGY...
No hydrologic impacts are expected into next week. It is too early
to know if thunderstorms mid to late week could pose any hydrologic
impacts.

&&

.TIDES/COASTAL FLOODING...
Isolated minor coastal flooding along the western south shore
bays and southern Fairfield seems likely with the evening high
tides cycles tonight.

A low rip current risk is forecast today as surf heights and
incoming swell should remain low.

A high risk is forecast for Sunday as winds and seas ramp up
after a warm frontal passage. The risk will be exacerbated by
greater than usual tidal ranges with tonight`s full moon.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 8 AM Sunday to 6 AM EDT Monday for
     ANZ350-353-355.

&&

$$
SYNOPSIS...JC/JP
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JP
AVIATION...JP
MARINE...JC/JP
HYDROLOGY...JC/JP
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion