Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 240133
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
933 PM EDT Fri Jun 23 2017

.SYNOPSIS...
A cold front will slowly approach tonight, eventually moving
across Saturday morning into Saturday afternoon. A secondary
cold front moves across Saturday night. High pressure builds to
our southwest Sunday into Monday. A weak cold front will move
through our area later Monday. High pressure builds towards the
Mid Atlantic coast Tuesday and Wednesday, before moving offshore
Thursday. Unsettled weather return for the end of the week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Severe thunderstorm watch has been cancelled. Primary threat
with any remaining thunderstorms will be localized flash
flooding in a very tropical air mass as the remnants of Tropical
Storm Cindy move northeastward along an approaching cold front.
More details can be found in the hydrology section below.

Previous discussion...

Elevated instability as diagnosed from Showalter indices only
slightly negative so have lowered coverage of thunderstorms
overnight to isolated in forecast overnight. Shear further
increases with low level jet tonight as SW winds increase to
45-55 kt between 3 and 4 kft, so any thunderstorm that develops
could be strong with gusty winds with a marginal threat that
thunderstorms could be severe.

Lows tonight were a blend of NAM12/GMOS and adjusted slightly
higher. Overall, temperatures will not drop much from this
evening through the night. Boundary layer moistens overnight
with patchy fog developing, especially in areas that are outside
the rain showers.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Starting out Saturday morning, the remnant low of Cindy with
the showers and thunderstorms will be near to just southwest of
the region. Heavy rain threat remains early in the morning with
patchy fog early especially in areas outside of rain showers. It
moves south of Long Island Saturday afternoon as the cold front
moves across. The showers and thunderstorms move offshore in
the afternoon as winds become more westerly. Depending on how
fast clouds decrease, the surface temperatures could warm up
quickly. Expecting an above normal day regarding temperatures
with boundary layer mixing giving highs mid to upper 80s most
places with some lower 90s in Northeast NJ using GMOS with
slight adjustments.

For Saturday night, a secondary cold front moves across which
will result in winds becoming more northerly late Saturday night
after its passage. Dry conditions, light winds and continued
mostly clear conditions will result in radiational cooling. A
vast range of lows will be seen in the region from upper 50s in
rural inland sections to lower 70s in parts of NYC from the MET
guidance.

A moderate risk of rip currents is forecast for Saturday.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Dry conditions expected on Sunday as a ridge of high pressure builds
towards the Mid Atlantic coast. Expect high temperatures to be in
the low to mid 80s on Sunday. A weak surface cold front will affect
the local area Monday afternoon into Tuesday. The system will not
have a great deal of moisture associated with it, but cooler
temperatures aloft may  spark off a shower or t-storm late Monday
into early Tuesday. High temperatures on Monday and Tuesday are
expected to be in the mid to upper 70s to lower 80s.

High pressure continues to build towards the area on Wednesday and
slowly moves offshore on Friday. A few showers are possible Friday
afternoon. Temperatures will start out in the upper 70s to near 80
on Wednesday then slowly increase to mid to upper 80s by Friday.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A cold front approaches this evening, then slowly moves through
the terminals by around 12 to 16Z tomorrow morning. Initial area
of thunderstorms will gradually decrease in intensity as they
approach the western-most terminals this evening - including the
NYC metro area. Additional showers and thunderstorms are
expected overnight with the approach of the cold front, with
heavy rain and reduced visibility possible at times.

Winds for most of the night will be from the south-southwest
with occasional gusts to around 20 kt possible. A low level jet
will move up the coast, with a brief period of LLWS possible
primarily at LGA/JFK/ISP and to a lesser extent elsewhere.
Following the front tomorrow morning, winds will shift to west-
northwest with increasing gusts through the day and decreasing
cloud cover.


     NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Amendments possible for showers and
thunderstorms. Wind gusts may be stronger than forecast for
tomorrow.

KLGA TAF Comments: Amendments possible for showers and
thunderstorms. Wind gusts may be stronger than forecast for
tomorrow.

KEWR TAF Comments: Amendments possible for showers and
thunderstorms. Wind gusts may be stronger than forecast for
tomorrow.

KTEB TAF Comments: Amendments possible for showers and
thunderstorms. Wind gusts may be stronger than forecast for
tomorrow.

KHPN TAF Comments: Amendments possible for showers and
thunderstorms. Wind gusts may be stronger than forecast for
tomorrow.

KISP TAF Comments: Amendments possible for showers and
thunderstorms. Low chance of IFR conditions developing
overnight. Wind gusts may be stronger than forecast for
tomorrow.

.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.Saturday night-Sunday Night...VFR. Gusty WNW flow diminishing
in the evening.
.Monday-Tuesday...VFR. A chance of shra/tsra Monday afternoon into
Tuesday.
.Wednesday...VFR.

&&

.MARINE...
Conditions on the waters are becoming more rough. Sub SCA winds
on non-ocean waters are expected through Saturday night. Ocean
stays in SCA through much of Saturday night. Less SCA winds
Saturday night with an overall weak pressure gradient with
residual higher seas.

Conditions across the area waters are expected to remain below
small craft advisory levels Sunday through the middle of the
week.

&&

.HYDROLOGY...
The potential for minor urban and poor drainage flooding with
localized possible flash flooding will remain with the showers
and thunderstorms forecast through early Saturday. Total rain
expected is 0.5 to 1 inch with locally higher amounts. The
precipitable waters increase to near 2.3 to 2.4 inches early
Saturday with tropical moisture from the remnants of Cindy
getting entrained along the front.

There is a threat for flash flooding late tonight through
Saturday morning from a likely complex of showers and
thunderstorm associated with a frontal wave (remnants of Cindy)
moving through the areas. Uncertainty exists on the exact track
of this wave...which could be from the Northern Mid- Atlantic
to Southern New England.

There are no hydrologic impacts expected Sunday and through the
end of the week.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides are running very high, especially during the
evening high tide cycles tonight and Saturday.

Less than 1 ft of surge is needed during these evening high tide
cycles for minor flooding, and in some cases less then 1/2 ft.
The expected S/SW flow is not favorable for surge, but a
background anomaly will likely be enough for minor coastal
flooding of the most vulnerable coastal locales along the south
shore bays of Western Long Island, along Jamaica Bay, and along
western Long Island Sound during this time.

&&

.EQUIPMENT...
KOKX weather radar is scheduled for maintenance starting today June
23rd for a period of 3 days.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ355.
     Small Craft Advisory until 6 AM EDT Sunday for ANZ350-353.

&&

$$
SYNOPSIS...Fig/JM
NEAR TERM...JMC/MD/JM
SHORT TERM...JM
LONG TERM...Fig
AVIATION...MD/MET
MARINE...Fig/JM
HYDROLOGY...Fig/JM
TIDES/COASTAL FLOODING...
EQUIPMENT...



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