Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 271136
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
736 AM EDT WED JUL 27 2016

.SYNOPSIS...
Weak high pressure will remain through tonight, then weaken on
Thursday. A weak cold front will approach Thursday night, and
remain nearby into the weekend as a few waves of low pressure
pass nearby. High pressure will return early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Made some minor adjustments to temps and dewpoints to reflect
current observations.

Otherwise, expect sunny skies to start, then high clouds mainly
this afternoon as a mid level shortwave approaches in zonal flow
aloft. High temps should be a shade hotter this afternoon than
those of yesterday inland, still mostly lower 90s, while coastal
sea breezes cap temps in the upper 80s along the south shore of
Long Island and SE CT. Heat indices should be close to ambient
temps for the most part via lower dewpoints in the lower 60s, but
afternoon sea breezes bringing in more humid marine air with
dewpoints in the upper 60s could boost heat indices right along
the coast to just above ambient temps.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Expect mostly clear skies tonight as the aforementioned shortwave
passes by. GFS tries to produce some light precip in association
with this wave, but this does not look realistic as the air mass
in place should still be fairly dry and stable. Low temps will be
close to or slightly warmer than those expected for early this
morning, in the 70s invof NYC and across western Long Island,
and in the 60s elsewhere.

Thu looks like another hot and increasingly humid day, with high
temps in the lower 90s for NYC metro and inland sections, and upper
80s near south facing shores. Dewpoints increasing to the upper
60s to near 70 from NYC metro east should push heat index values
into the mid/upper 90s in those areas, with lower 90s elsewhere.

Zonal flow aloft turns a little more SW through the day on Thu,
and the combo of an approaching mid level shortwave and
convergence invof a weak inland thermal trough and along sea
breeze boundaries should spark at least isold convection. The 00Z
SBU NAM/GFS WRF and the NCAR ensemble are all signaling more
focused development along the sea breeze in NYC metro and across
Long Island where greater instability will also reside, as
increasing dewpoints push MLCAPE to 1000-1500 J/kg across Long
Island and 500-1000 J/kg most elsewhere, so have scattered PoP for
those areas in the afternoon.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A low pressure system will move from the Mid-Atlantic northeastward
Thursday night into Friday night, resulting in showers and
thunderstorms across the area. There is the potential for locally
heavy rainfall with precipitable water values in excess of 2 inches.
As the wave of low pressure departs, there may be a break in the
precipitation Saturday, but isolated to widely scattered showers
cannot be ruled out. More unsettled conditions are possible Saturday
night into Sunday, as another potential short wave moves through.
Will continue mention of chance pops due to model differences at
this time. High pressure builds in from Canada early next week.

Temperatures look to be near seasonable levels Friday into early
next week.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
High pressure builds in from the west today and then east tonight.

Vfr through the period.

Light northerly winds back to the W/WSW late this morning/early
afternoon...except likely holding NE at KLGA. Southerly sea breeze
development expected at coastal terminals in early
afternoon...expected at KLGA/KHPN by late afternoon...with
moderate potential of se sea breeze at KEWR/KTEB in late
afternoon. Winds diminish to light s/sw flow.

     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: High probability of southerly sea breeze this
afternoon...with most likely timing of onset between 16z and 18z.

KLGA TAF Comments: NE winds likely through 15 to 17z. High
probability in southerly sea breeze this afternoon...with most
likely timing of onset between 19z and 21z.

KEWR TAF Comments: Moderate probability of southeast sea breeze this
afternoon...with most likely timing of onset between 20z and 22z.
Sea breeze may waver near the airport for a few hours this
afternoon...before passing through.

The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: Moderate probability of sse sea breeze this
afternoon...with most likely timing of onset between 20z and 22z.
Sea breeze may waver near the airport for a few hours this
afternoon...before passing through.

KHPN TAF Comments: No unscheduled amendments.

KISP TAF Comments: High probability of southerly sea breeze this
afternoon...with most likely timing of onset between 17z and 19z.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.Thursday...VFR. Isolated showers and thunderstorms possible
Thursday afternoon, mainly NW of the NYC terminals.
.Thursday Night into Friday Night...MVFR or lower possible in
showers and thunderstorms. Patchy fog.
.Saturday into Sunday...Iso-Sct diurnal shra/tsra possible.

&&

.MARINE...
Sub-SCA conditions will prevail through the weekend.

&&

.HYDROLOGY...
There is potential for significant rainfall from late Thursday
night into Friday night. Locally heavy rainfall is possible, which
could cause flooding. It is still too early for specifics.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$


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