Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 261801
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
201 PM EDT Wed Apr 26 2017

.SYNOPSIS...
Weakening low pressure tracks very slowly northeast today south
of Long Island, passing southeast of Long Island tonight. The
low dissipates along the New England coast on Thursday. A
weakening cold front will approach from the northwest Thursday
and Thursday night, then also dissipates over the area on
Friday. Another cold front pushes south of the area Saturday
night. This front then moves back toward the area as a warm
front Sunday night into Monday with the associated cold front
moving through Monday night into Tuesday morning.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Any rainfall will be manifested as isolated to widely scattered
showers or just as drizzle for the remainder of the afternoon.
Temperatures and dewpoints mainly on track with dense fog
persisting across the eastern waters.

A closed upper low will lift slowly NE through the afternoon,
in tandem with the surface low both tracking south of Long
Island. This will keep the area under a weak NE flow.

Weak lift and saturated low levels will result in light rain
showers and/or drizzle for much of the day across parts of the
region. In addition, with the diminishing NE flow and saturated
low- levels, there will be some patchy fog.

Highs today will be near normal in the lower 60s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Weakening low pressure passes to the south and east of Long
Island tonight and dissipates along the New England coast on
Thursday.

Low-levels will remain moist with light NE winds. Widespread fog
and drizzle is forecast tonight. The fog may even become dense
overnight before gradually lifting on Thursday.

With a subsidence inversion on Thursday and the development of
a weak return SE flow, low clouds are likely to persist through
the day.

Overnight lows tonight will be mild in the lower to mid 50s,
with highs a bit warmer on Thursday, in the 60s to around 70.
The warmest readings will be across the interior Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
A surface cold front will approach the area Thursday night and
weaken as it does so. Although there does seem to be some lift and
instability in association with the front, it is not impressive and
only a slight chance of showers and a passing thunderstorm is
possible.

Bermuda type high pressure will set up over the north central
Atlantic. This will bring in some warmth and humidity to the area.
Temperatures away from the coast will reach the upper 70s to lower
80s, while temperatures near the coast will remain in the lower to
middle 70s, with perhaps some upper 60s along the immediate coast.
Dew points will rise into the upper 50s to perhaps some lower 60s.

The next cold front approaches from the northwest Saturday and
pushes south of the area late in the day. This front looks to be a
bit stronger than the previous one, with some lift noted in the
middle and upper levels, but again, nothing too impressive. Most
unstable CAPE values however are in the 1000-2500 J/kg range, mainly
away from the coast, where conditions will be warmest. Lifted index
values of -3 to -5 noted in the 00Z GFS. So, showers and a passing
thunderstorm is once again possible Saturday. If further model runs
continue with these values, some strong to severe storms are
possible, but its too early right now.

High pressure builds in for Saturday night and Sunday, with the cold
front settling to our south. The front will then move back north as
a warm front Sunday night into Monday, with a return to unsettled
conditions starting Sunday. The warm front lifts north on Monday,
with the cold front quickly approaching and moving through Monday
night into Tuesday.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Low pressure approx 50 miles SSE of KJFK will start to slowly
shift east this afternoon and evening.

Mostly IFR expected, however some prevailing or tempo MVFR cigs
expected mainly west of the Hudson River. A stray brief shower
or two is still possible this aftn.

NE-N winds around 10 KT becoming a little lighter late this
aftn. Winds eventually bcmg light and variable this evening.

     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: CHC cigs prevail or tempo 1000-1300 FT for a
couple hours this afternoon.

KLGA TAF Comments: CHC cigs prevail or tempo 1000-1300 FT for a
couple hours this afternoon.

KEWR TAF Comments: Tempo or prevailing IFR cigs still possible
this aftn. Timing of return to prevailing IFR may be off by an
hour or two.

KTEB TAF Comments: Improvement to MVFR cig may be delayed by an
hour or two. Thereafter, tempo or prevailing IFR cigs still
possible this aftn. Timing of return to prevailing IFR may be
off by an hour or two.

KHPN TAF Comments: CHC cigs prevail or tempo 1000-1300 FT for a
couple hours this afternoon.

KISP TAF Comments: Timing of vsby dropping below 3/4SM may be
off by a couple of hours or potentially might not happen at all
tonight.

.OUTLOOK FOR 18Z THURSDAY THROUGH SUNDAY...
.Thursday aftn...MVFR.
.Thursday night...MVFR with chc IFR.
.Friday...Chance showers/thunderstorms/MVFR AM, VFR PM.
.Saturday...Mainly VFR.
.Sunday...Mainly VFR.

&&

.MARINE...
Dense fog remains across the eastern waters today and could very
well extend through tonight. This could spread westward as well
late today into this evening across more western waters.

SCA for hazardous seas remains up on the ocean waters through
Thursday night due to an easterly swell as weakening low
pressure slowly lifts NE from the Delmarva this morning to the
New England coast on Thursday.

Waves remain above SCA criteria through Friday and much of Friday
night. Waves remain below 5 ft through Sunday night, though there
may be a brief period of 5 ft waves on the ocean as south to
southwesterly flow builds ahead of an approaching cold front.

Better chances of seeing SCA criteria on the ocean and back bays
Monday into Monday night as a stronger frontal system impacts the
region. Waves on the ocean build to 5 ft Monday, and up to 8 ft by
Monday night. Gusts of 25 to 30 kt are possible for the ocean and
back bays Monday into Monday night, diminishing late Monday
night.

&&

.HYDROLOGY...
No significant rainfall expected. Rain amounts through early
Friday are generally expected to remain below a quarter of an
inch. However, there may be isolated brief heavy downpours in
any thunderstorms that develop during the forecast period.

&&

.TIDES/COASTAL FLOODING...
Due to high astronomical tides and an easterly swell the next
couple of days, water levels may approach minor coastal flood
benchmarks, in particular across the south shore back bays of
western LI. Only 1/3 to 3/4 of a foot of surge is needed for
minor flooding. A coastal flood statement has been issued for
this evening`s high tide cycle for these locations.

In addition, the elevated water levels combined with a prolonged
period of 5-9 ft breaking surf tonight into Thu will result in
beach erosion issues and may cause some localized dune toe
erosion during the high tides.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT Friday
     for ANZ350-353-355.
     Dense Fog Advisory until 4 PM EDT this afternoon for ANZ330-
     340-350.

&&

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


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