Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
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FXUS61 KOKX 291155
Area Forecast Discussion
National Weather Service New York NY
755 AM EDT FRI JUL 29 2016
Low pressure just off the southern New Jersey coast passes to the
south and east of Long Island through this afternoon. High
pressure will then briefly build into the region tonight into the
first half of Saturday, giving way to low pressure approaching
from the Ohio Valley later in the day. This low will pass to the
north as a few waves of low pressure pass along a frontal boundary
to the south into early next week. High pressure then returns for
the middle of the week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Flash flood watch has been dropped. Back edge of rain is
approaching the NYC metro and should clear eastern LI and SE CT
by late morning. Surface low continues to trend farther south and
more progressive. There have been pockets of embedded heavy rain
with up to half an inch hour, resulting in mainly minor poor
drainage flooding. An additional quarter to one inch of rainfall
is possible this morning from NYC and points east with the highest
amounts falling across eastern LI and SE CT.
Partly sunny skies will develop from west to east from mid morning
into early this afternoon.
Daytime highs will range from the upper 70s to lower 80s, possibly
warmer with more sun now expected. It will remain very humid with
dew points around 70 and little change in airmass on the backside
of the low this afternoon.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Weak ridging builds behind the shortwave tonight with surface
high pressure building from the northwest. Lows will be near
seasonable levels, but remaining muggy.
Weak high pressure will remain over the region Saturday morning,
resulting in a dry Saturday morning. Models have trended quicker
with the next approaching shortwave, which may trigger scattered
showers and thunderstorms as early as Saturday afternoon. Eastern
LI and SE CT may be able to remain dry most of the day. Highs
also will be near seasonable levels.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Latest NWP guidance in fair agreement with the H5 pattern across
North America consisting of strong high pressure over the southwest
US...a Bermuda high over the western Atlantic and a mean trough
extending from west of the Rockies to the east coast this weekend.
Early next week the high out west expands back into the southern
Plains sharpening the trough east of the Mississippi. The trough
moves east of the area on Tue with upper level ridging building in
for the middle of the week.
Model trends over the past 24 hours have sped up the weekend
system with pcpn moving in during the day Sat. The shortwave is
lagging behind the RRQ of a 65kt upper jet...but could have decent
warm rain processes with PW`s around 2 inches. However...the GFS
looks suspicious aloft between 00z and 12z developing a coupled
vort max/min in the mid levels thus enhancing pcpn total at the
sfc. So...while there will likely be overrunning Sat night with a
frontal boundary to our south...the best dynamics associated with
the shortwave appear to pass to the N on Sun with the majority of
the rainfall likely remaining to our N with areas N and W of NYC
having the best chance to see pcpn. A few weak waves of low pres
does develop along the boundary Sun and Sun night...but they look
to pass too far S to have any real impact on the region. Have
remained with chc pops for most of the area during this time
except NW zones which will be closest to the upper jet and
shortwave energy. There is also uncertainty with the location of
the frontal boundary. EC is further N with it on Sun tracking the
waves directly over the local area.
Upper trough axis approaches Mon and moves through Mon night with
sct showers/thunderstorms expected during this time. An isolated
shower is possible on Tue although there may not be enough
moisture and we could be capped as upper level ridging begins to
The remainder of the week looks dry with increasing heat and
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --Low pressure along the Mid Atlantic coast will pass to the south
today. Associated rain will bring mainly MVFR conditions, perhaps
brief IFR to KISP, before ending from mid to late morning NYC
metro and early this afternoon at KBDR/KISP/KGON. MVFR cigs could
linger a little longer than forecast after rain ends--otherwise
VFR conditions should take hold thereafter through must of
tonight. Some light fog with MVFR vsby could occur late tonight
outside of the NYC metro.
...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: MVFR cigs could persist another hour after rain
KLGA TAF Comments: MVFR cigs could persist another hour after rain
KEWR TAF Comments: MVFR cigs could persist another hour after rain
The afternoon KEWR haze potential forecast is yellow, which
implies slant range visibility 4-6SM outside of cloud.
KTEB TAF Comments: MVFR cigs could persist another hour after rain
KHPN TAF Comments: No unscheduled AMD.
KISP TAF Comments: MVFR cigs could persist another hour after rain
.OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
.Saturday afternoon into Sunday...Chance of showers and possibly a
tstm. MVFR or lower conditions possible.
.Sunday night-Monday night...Chance of showers. MVFR conditions
-- End Changed Discussion --
Winds and seas are expected to remain below small craft advisory
levels through Saturday. Low pressure is forecast to track south
of the waters today with strengthening E/NE winds through this
afternoon. Winds and seas are forecast to remain below SCA, but
could gusts up to around 20 kt, especially on the ocean waters
east of Moriches Inlet. Winds diminish tonight as high pressure
builds across the waters.
Sub-advsy conds are then expected through the rest of the forecast
An additional one quarter to one inch of rainfall is possible from
NYC and points east this morning. Minor poor drainage flooding is
The next chance for organized rainfall Saturday into Sunday.
Less than an inch is expected.