Area Forecast Discussion
Issued by NWS Upton, NY

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611
FXUS61 KOKX 290251
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1051 PM EDT THU JUL 28 2016

.SYNOPSIS...
Low pressure approaches from the southwest tonight and passes
through the region Friday. The low departs late in the day Friday
with high pressure building to the north. Weak high pressure
briefly builds into the region for parts of Saturday. Unsettled
weather returns Saturday night through Sunday night with the
passage of another low pressure system. Drier weather is expected
for the first half of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The widespread area of heavy showers and thunderstorms have
weakened over Orange County, all that remains is some light rain
over the Lower Hudson Valley and Northeast New Jersey. An area of
light to moderate rain moving into Northwest New Jersey moving
northeast should move into the area over the next couple of hours.
Since much of the rain is not associated with thunder, took
mention of scattered thunderstorms out and went with isolated
instead. Otherwise, only minor changes made.

A coastal trough remains along with a deepening low over
Virginia. This low is associated with the vigorous shortwave
moving through the northern trough over the eastern states. A
combination of the deepening low and warm frontogenesis through
southern NJ to south of Long Island 03z to 06z will bring
increasing chances for showers, and with marginal instability
thunderstorms. A deep layered southwest flow around sub tropical
high pressure off southern coast and into the northern stream
trough was transporting tropical moisture into the region. There
will be potential for heavy rain developing later this evening
and overnight as lift increases with the frontogenesis. A flash
flood watch has been posted to this evening and into Friday.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Timing and tracking of the deepening low across the region during
Friday is still somewhat uncertain, although there is now more
consistency with the low tracking just south of Long Island
Friday afternoon. Increasing shear along the warm front late
tonight into Friday afternoon will increase the threat of severe
storms across metro NYC, Long Island, and into coastal CT, along
with continues heavy rainfall. Speed of the low has increased and
precipitation is now expected to taper off from the west during
the afternoon. Weak ridging builds behind the shortwave late
Friday into Friday night with surface high pressure building from
the northwest. Friday night will be dry with a cooler airmass
moving into the area.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Weak high pressure will remain over the region Saturday morning,
resulting in a dry Saturday morning. An approaching shortwave may
set off a few scattered showers and thunderstorms Saturday
afternoon, mainly west of NYC. East of NYC, conditions appear to
remain mostly dry. The unsettled weather becomes more widespread
Saturday night into Monday, as the shortwave and its associated low
pressure system moves across the region. Expect showers and
thunderstorms, through this time frame with some storms producing
locally heavy rainfall.

High pressure builds back into the region early next week, providing
mostly dry conditions. A few isolated showers or thunderstorms
cannot be ruled out during the first half of next week...mainly N
and W of NYC during the afternoon hours.

Temperatures will remain seasonable through the long term with
highs each day climbing into the 80s.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
  High Impact Weather Forecast until 18z Friday...

Low pressure approaches from the southwest overnight and passes
through the region Friday.

VFR through 6-9Z or so, then widespread MVFR/IFR conditions in
moderate to heavy rain with embedded thunderstorms are forecast
north of the low`s track, through 16z Friday.

There is a potential for thunderstorms with damaging wind gusts along
and south of the lows` track along coastal NJ, NYC, and
Long Island.

Weather conditions improve from west to east 18z-23z Friday.

Light south winds back to the east overnight. Then winds back to the
north after 12z as the low passes just south.

.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.Friday night until Noon Saturday...VFR.
.Saturday afternoon into Monday Night...Chance of showers/tstms
with MVFR or lower conds at times possible.
.Tuesday...Mainly VFR.

&&

.MARINE...
Winds and seas are expected to remain below small craft advisory
levels tonight through Friday. A wave of low pressure is forecast
to track through or near the waters Friday. Depending on the track
of the low briefly higher winds and seas near small craft levels
will be possible on the ocean waters east of Moriches Inlet.

Showers and thunderstorms will be possible from this evening
through Friday. Some of the thunderstorms Friday may produce gusty
winds in excess of 35 KTS, especially over the ocean waters. At
this time fog formation is not expected.

A light pressure gradient over the area waters will result in sub-
sca conditions this weekend and early next week. However, any
thunderstorms that develop on the waters may produce brief SCA
conditions.

&&

.HYDROLOGY...
A flash flood watch is in effect for the entire CWA tonight
through Friday for the potential of 2 to 4 inches with locally
higher amounts. The axis of heaviest rain at this time is expected
across northeastern New Jersey into the Lower Hudson Valley and
NYC, and into southwestern Connecticut. Uncertainty remains as to
where the heaviest rain occurs and depends on the track of low
pressure through the region. Also, the speed of the low will
affect the timing of precipitation.

Another round of showers and thunderstorms can be expected Saturday
night through Sunday...with some storms possibly producing heavy
rainfall. Exact precipitation amounts are unclear at this time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flash Flood Watch through Friday afternoon for CTZ005>012.
NY...Flash Flood Watch through Friday afternoon for NYZ067>075-
     078>081-176>179.
NJ...Flash Flood Watch through Friday afternoon for NJZ002-004-006-
     103>108.
MARINE...None.

&&

$$
SYNOPSIS...BC/MET
NEAR TERM...JP
SHORT TERM...MET
LONG TERM...BC
AVIATION...PW
MARINE...BC/JP/MET
HYDROLOGY...BC/MET



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