Grassy Point, New York Weather Forecast Discussion

548
FXUS61 KOKX 131447
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1047 AM EDT Sat Sep 13 2025
.SYNOPSIS...
High pressure over the area gradually weakens this weekend
while slowly moving offshore. A weak cold front approaches
Sunday and moves across Sunday night. A new area of high
pressure then builds in from the north and west for early next
week. A weak low to the south may graze the area Wednesday
night into Thursday, followed by weak high pressure on Friday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Just made some minor adjustments with temperatures, dewpoints,
cloud coverage and patchy fog to better match with observed
trends. Otherwise, forecast remains on track.
Into the morning hours, mid level clouds more prevalent across
western areas. In addition, especially outside of clouds,
patchy fog for locations reaching saturation, particularly
inland and rural valley sections.
During the day, synoptic southerly flow from high pressure moving
offshore but overall weakening. A little bit of convergence with sea
breeze enhancement and some positive vorticity advection aloft will
enable for a few rain showers to develop. Model CAPE limited to near
100 J/kg or less, so left out thunder. The sparse coverage of
showers forecast as denoted from a few CAMs limited POPs to slight
chance. Some locations due to ambient drier low levels may end up
just getting some sprinkles.
Forecast high temperatures range from the lower 70s for eastern
coastline to lower 80s for parts of interior north and west of NYC.
These values are from NBM. The NBM high temperatures near the coast
seem to be in general agreement with a consensus of MOS but are a
few degrees higher for urban and interior areas.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
For tonight, the loss of diurnal heating will make for lessening
instability. Any remaining showers are expected to dissipate.
Otherwise, weakening high pressure will allow for a dry airmass with
southerly light winds becoming more variable. Patchy fog will be
possible late at night into early Sunday morning for those locations
that radiatively cool more, mostly across the interior where winds
become nearly calm.
Forecast lows tonight are mainly in the upper 50s to lower 60s.
Weakening high pressure will allow for a weak cold front to
approach the region Sunday. This weak cold front will move
across the region Sunday night.
More low level warm air advection expected for Sunday, allowing for
warmer surface temperatures. These will be several degrees warmer
than the previous day. Forecast high temperatures range from the mid
70s to mid 80s.
Models convey stronger shortwave energy aloft as diagnosed from
more positive vorticity advection along with more instability
(more between 100 and 200 J/kg CAPE) will present a possibility
for showers and thunderstorms. The front with its weakening
structure and limited moisture content will have associated
convective coverage limited to no more than sparse. The POPs as
a result are mostly slight chance to low end chance with low end
chance across north and eastern portions of New London CT. The
CAMs depict sparse convection developing during the afternoon,
mostly across the interior.
Post cold front, temperatures trend down slightly as winds
transition to more northerly and eventually more easterly. Dry
conditions will remain thereafter through Monday night. Lows
forecast Sunday night range from the lower 50s to mid 60s. Forecast
highs on Monday return to a lower 70s to lower 80s range. Lows
forecast Monday night range mainly from mid 50s to lower 60s.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Key Points:
* Dry conditions with seasonable temperatures are forecast through
  Wednesday afternoon.
* A weak low to the south may graze the area Wednesday night into
  Thursday.
* Dry and warmer conditions are possible for Friday.
Ridging will continue to build over much of the eastern CONUS Monday
and Tuesday. The modeling still indicates energy getting stuck
underneath the ridge across the southeast, likely forming a broad
cutoff low by mid week. The uncertainty lies with its location by
later this week, with the GFS faster (Wed night-Thu) and ECMWF
slower (Thu-Thu night). NBM guidance sides with the fast GFS idea.
After this low pulls away, weak sfc ridging should return with above
normal temps for Fri.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
VFR as high pressure over the area shifts just offshore today.
A weakening cold front will approach from the northwest this
afternoon.
VFR. Can`t rule out a stray shower mid to late afternoon at or
near KSWF/KHPN/KBDR.
Light winds increasing closer to 10 kt at the NYC metros and
right along the coast during the afternoon (KISP/KBDR/KGON). SE
sea breeze should reach KEWR by 19Z if not earlier. KSWF will be
the exception to this, with light WSW flow today.
Winds become S and diminish tonight, becoming light SW or
light/vrb after midnight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected.
.OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sunday: Mainly VFR. Slight chance of an afternoon shower or
tstm as another weak cold front approaches.
Sunday night through Wednesday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
With high pressure staying nearby and weakening, pressure
gradient will be weakening also. Winds and seas are forecast to
remain well below SCA thresholds through early next week.
Weak pressure gradient remains with weak low pressure
approaching nearby potentially for middle of next week, so
conditions look to stay below SCA thresholds.
&&
.HYDROLOGY...
Any rainfall this weekend is expected to be quite limited in
both temporal and spatial coverage. As such, no flooding is
expected and the rain is not expected to sufficiently wet the
ground. Less than a tenth of an inch of rainfall is forecast.
There are no hydrologic concerns through next week.
&&
.TIDES/COASTAL FLOODING...
Rip current risk for ocean beaches this weekend is low with
winds staying light and less onshore swell. Southerly winds stay
mostly in 5-10 kt range and waves stay near 2-3 ft.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BG
AVIATION...JMC/BG
MARINE...BG/JM
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion