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266
FXUS61 KOKX 292017
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
417 PM EDT Sat Jun 29 2024

.SYNOPSIS...
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A warm front moves northeast of the region going into this
evening. A cold front approaches tonight into early Sunday and
moves across the area Sunday afternoon into Sunday night. High
pressure builds into the area from the northwest Monday through
Tuesday and pushes offshore late Tuesday into Tuesday night. A
warm front lifts north of the area on Wednesday. A cold front
approaches Wednesday night and stalls near the area through the
end of next week into the first half of next weekend.
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&&

.NEAR TERM /UNTIL 8 AM SUNDAY MORNING/...
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Large scale numerical weather prediction models show a consensus
with mid level height falls tonight into Sunday morning. They show
highest mid level positive vorticity advection tonight with some
negative vorticity advection Sunday morning.

At the surface, a warm front will be moving farther northeast of the
region. The local region will become more within the warm sector of
low pressure system to the west.

The models indicate 0-6 km bulk shear around 30 kt tonight into
Sunday morning. Elevated instability as diagnosed from negative
Showalter Indices from the models are from near -1 to almost -4
degrees C. Some thunderstorms could be strong with potential for
gusty winds.

CAMs depict convection moving in this evening with much of the area
seeing convection in between 8pm this evening and 4am overnight.

PWATs increase to a little over 2 inches, generally near 2.2 to 2.3
inches. Flooding will be possible with thunderstorms but would
expect mostly localized minor flooding.
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&&

.SHORT TERM /8 AM SUNDAY MORNING THROUGH MONDAY/...
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Large scale numerical weather prediction models show a
consensus with mid level height falls continuing Sunday
afternoon through Sunday night. This will be ahead of an
approaching strong shortwave from eastern part of the Great
Lakes through SE Canada. The height falls appear to occur more
rapidly compared to the previous night.

The models indicate a return of positive vorticity advection
Sunday afternoon into early Sunday evening.

The models show 0-6 km bulk shear increases to near 40-50 kt
and potentially above 50 kt as well. This combined with surface
instability as conveyed by CAPE values between 2000 and 4000
J/kg across the region near NYC and locations north and west.
Less CAPE to the east with more marine influence. There will be
potential for strong to severe thunderstorms with damaging winds
and large hail possible. Primary threat would be damaging
winds.

The forcing further is evident from the local region being
relatively closer to the right rear quad of an upper level jet
streak from SE to NE from New England into the Canadian
Maritimes. This will provide for greater divergence aloft.

CAMs show ongoing convection south of Long Island for early
Sunday morning in the 6am to 10am timeframe. Then, shower
activity sparse with mainly dry conditions thereafter until
around 1-2 pm. From 1-2 pm, convection starts to redevelop north
and west of the forecast and may start to move into parts of
the Lower Hudson Valley. Between 2 and 5pm, the convection
develops and solidifies into a squall line as it moves southeast
farther into the local region, reaching through Southern CT,
northeast NJ, Lower Hudson Valley, NYC into much of Long Island.
Convection expected to linger across much of the area Sunday
evening with much of the activity gradually shifting to more
eastern locations.

PWATs will remain a little above 2 inches Sunday into early
Sunday evening for much of the region, again near 2.2 inches.
Flooding will remain possible with thunderstorms.

Also to note, some indication with max updraft helicity across
parts of the region, mainly across interior. This signals a
potential for rotation within thunderstorms. A brief tornado
cannot be ruled out.

Overnight, dry conditions expected to re-establish across the
region from NW to SE.
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&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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The cold front will continue to push offshore Monday morning as the
upper level trough over western and central portions of the
Northeast treks southeast. This will be the focus for some lingering
showers for eastern areas Monday morning and early afternoon. The
high continues to build in for Tuesday and pushes offshore late in
the day Tuesday into Tuesday night. Meanwhile, upper level ridging
over the Great Lakes noses into the Northeast. This allows a warm
front to lift north of the region sometime on Wednesday, and the
associated cold front to start moving through sometime on Thursday,
which then may stall somewhere near the area through the end of the
week.

With high pressure in place, conditions should be dry through
Wednesday as the warm front lifts north too far west to bring any
precipitation. Precipitation is expected with the approaching cold
front and chances for showers and thunderstorms look to continue
through the first half of next weekend.

As for temperatures, they are expected to be seasonable through
Wednesday. With upper level riding nosing in on Thursday, warmer
conditions are forecast, with highs in the upper 80s to lower 90s
away from the coast. Similar readings are expected through Saturday.
Humidity levels will also be on the rise. Prior to Wednesday night,
dew points will generally be in the 50s to around 60. From Wednesday
night onward, dew points rise into the 60s to around 70.
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&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
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A warm front approaches this afternoon and moves through this
evening. A pre-frontal trough approaches tonight and settles nearby
on Sunday.

VFR conditions prevail for the next few hours. Cigs lower to MVFR
this evening towards 22 to 00z, and then to IFR at most terminals
for the overnight. LIFR conds with tstms possible mainly after
midnight, with any LIFT conds likely confined to KHPN, KISP, KGON,
and potentially KJFK. There is the potential for some FG early Sun
morning, especially for eastern terminals and after any SHRA and
TSRA tapers late in the overnight. Confidence remains too low to
include in TAFs at this time.

Winds will be SE and S this afternoon, with most terminals S for
this evening. Winds at most coastal terminals gust to 20 to 25 kt
this afternoon, with a few gusts closer to 30 kt at KLGA and KJFK.
The winds are expected to become more SW Sunday morning. For eastern
most terminals possible LLWS from 6z to 12z Sun, but confidence of
occurrence remains too low to include in TAFs.

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

Timing of sub VFR conditions returning this evening may be off by a
couple of hours. Amendments may be needed with changing flight cats
this evening and through the overnight, and into Sunday morning.


OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...

Sunday afternoon and evening: VFR gives way to a period of MVFR and
possible IFR cond with TSRA containing gusty winds. VFR returns for
Sunday night.

Monday through Wednesday: VFR.

Thursday: Mainly VFR, with possible sub VFR later in the day and at
night in possible SHRA or TSRA.

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

.MARINE...
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SCA in effect for all waters until midnight. Then SCA remains on
South Shore Bays and ocean through Sunday early evening. The
ocean has SCA remaining through all of Sunday evening. Sub-SCA
conditions expected Sunday overnight into early Monday.

Winds and waves are expected to remain below SCA criteria from
Monday through Friday. However, late day winds in the NY Bight area
just E of Sandy Hook could gust close to 25 kt both Wed through Fri
afternoons.
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&&

.HYDROLOGY...
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Minor flooding possible with thunderstorms through tonight.
Minor flooding more probable Sunday into Sunday evening.
Localized flash flooding cannot be ruled out. Total rainfall
amounts through Sunday evening between a half to 1 inch, with
locally higher amounts possible.

Locally heavy rainfall may be possible Thu night into Fri with a
passing frontal system.
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&&

.TIDES/COASTAL FLOODING...
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The rip current risk is high this afternoon and evening with
strengthening SE winds and building seas.

The high risk continues into Sunday with swells of 5-6 ft and 7
second period.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...High Risk for Rip Currents through Sunday evening for NYZ075-080-
     081-178-179.
NJ...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ331-332-
     335-338-340.
     Small Craft Advisory until 8 PM EDT Sunday for ANZ345.
     Small Craft Advisory until midnight EDT Sunday night for
     ANZ350-353-355.
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&&

$$

SYNOPSIS...JM/JP
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JP
AVIATION...JE
MARINE...JM/JP
HYDROLOGY...JM/JP
TIDES/COASTAL FLOODING...