000
FXUS61 KOKX 181739
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
139 PM EDT Wed Oct 18 2023
.SYNOPSIS...
High pressure builds remains in control through Thursday. A
frontal system approaches Thursday night and impacts the region
Friday. A secondary low develops along the Delmarva Friday night
and deepens through Saturday night while tracking to the
northeast. The low departs to the northeast Sunday as high
pressure builds in from the west and settles over the region
early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Forecast mostly on track this afternoon. Moisture trapped
beneath a subsidence inversion between 7-10kft will continue to
lead to mostly cloudy conditions for much of the day. Sea breeze
convergence has developed some bands of cumulus of clouds along
it and cannot completely rule out an isolated shower. Have added
in a slight chance PoP this afternoon for the coastal region.
Skies may become partly cloudy over Long Island as weak sea
breeze circulation eventually helps mix out some of the
moisture.
Otherwise, surface high pressure will gradually build into the
region today, with a mostly dry day expected. Aloft, an upper
level low will be slow to exit. A few sprinkles cannot be ruled
out this afternoon. Otherwise, expect another day of more
clouds than sun with temperatures in the low to mid 60s.
Clearing skies tonight and light winds will allow overnight lows to
fall into the 40s for much of the region. The NYC metro area will
remain in the lower 50s. A a combination of MAV/MET and NBM were
used in the near term.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Thursday starts off with surface high pressure and weak ridging
aloft over the region. Expect a mostly sunny day. Winds will remain
relatively light to start, then become a bit more southerly as the
high starts to move east of the area during the afternoon. Highs on
Thursday will be in the middle and upper 60s, potentially
approaching 70s in the NYC/NJ metro area.
The surface high and upper level ridge shifts further east Thursday
night, allowing an upper level trough to approach from the west.
Some of the forecast guidance has a weak low developing Thursday
night off the Mid-Atlantic coast and starting to work its way
northward. Forecast guidance showing some of the lows associated
precipitation moving into the region Thursday night. There are
some model differences with the timing and placement of this
potential low development. It is possible that Thursday night
will remain dry, however will continue to maintain some slight
chance POPs mainly after 06z. With cloud cover increasing and a
southerly flow in place, lows will be in the 50s Thursday night.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A frontal system impacts the area Friday into Friday night. With
marginal instability and CAPE developing over the ocean and into the
eastern portions of the forecast area Friday night, with warm air
advecting northward with increasing isentropic lift there is the
chance of isolated thunder.
There remains differences with the timing and evolution of the
development of a secondary low off the coast in the vicinity of the
Delmarva Friday night into Saturday, however, confidence remains
that precipitation will be occurring with the development of this
low. And with additional marginal instability and CAPE during
Saturday, and with the low level low moving over the region, there
will again be a chance for isolated thunder mainly Saturday
afternoon.
With a strong pressure gradient increasing with the deepening low,
and cold advection setting up behind the departing low, a strong and
gusty west to northwest flow will be developing. The coldest air of
the autumn season will be moving into the region Sunday night.
Temperatures will be bear normal Friday and Saturday and below
normal, as much as 5 to 10 degrees, Sunday into the beginning of
next week. With clearing skies and winds becoming light both Monday
night and Tuesday night there is the potential for frost in the
outlying locations.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
High pressure remains overhead through tonight, moving offshore
Thursday. VFR through the forecast period.
General southerly flow this afternoon with speeds under 10 kt.
Winds lighten and become more SW this evening at the NYC
terminals, and light and variable at the outlying terminals. Low
chance of scattered clouds around 1500 ft along the coast
toward Thursday morning. Flow becomes S or SSE on Friday, with
speeds around 10 kt.
....NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of wind shifts may be off by an hour or two.
Low chance of brief MVFR cig/vsby at KJFK Fri AM.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
Thursday Afternoon: VFR.
Friday through Saturday: MVFR/IFR with showers.
Sunday: MVFR early, becoming VFR. W to NW wind gusts 25-30 kt.
Monday: VFR. Gusty NW flow.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
With high pressure in control, expect conditions to remain below
Small Craft Advisory Criteria through Thursday night.
With a persistent period of southeast flow Friday into Friday night,
ahead of an approaching frontal system, ocean seas may build to SCA
levels by late Friday night into Saturday morning, and build through
Saturday. As a secondary low develops along the Delmarva late
Friday, and deepens into Saturday night while tracking north, small
craft conditions are expected to develop on all the forecast waters
Saturday night and then continue into at least Sunday night, and
possibly into Monday as winds and seas gradually diminish. Small
craft conditions likely remain on the ocean waters into Monday
evening. The highest wind gusts on the ocean waters are expected
late Saturday night into Sunday evening with the potential for a
period of gales Sunday into Sunday night.
&&
.HYDROLOGY...
Potential for minor flooding Friday into Saturday. Otherwise no
other hydro problems expected.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BC/MET
NEAR TERM...BC/DS
SHORT TERM...BC
LONG TERM...MET
AVIATION...DR
MARINE...BC/MET
HYDROLOGY...BC/MET