Harriman, New York Weather Forecast Discussion

243
FXUS61 KOKX 181120
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
720 AM EDT Thu Sep 18 2025
.SYNOPSIS...
Low pressure gradually pulls away today with weak high pressure
nudging in from the southwest through tonight. A cold front moves
through Friday with high pressure building Friday night and
likely remaining in control through early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Clouds linger this morning with humid conditions remaining in place.
What is left of the mid and upper level trough will gradually
dissipate through the day. The WNW mid level flow picks up this
afternoon and this should aid in sky conditions improving from west
to east during the course of the day. BUFKIT profiles show the cloud
deck breaking up and lifting through the course of the morning.
Therefore partial sunshine develop for the late morning and early
afternoon, with clear skies setting up for the late day. Winds are
expected to remain light through the day as the pressure gradient
remains weak with low pressure staying weak and gradually lifting
away as it gets east of New England. With sunshine developing and no
real air mass change temperatures are expected to get warm for the
afternoon with mainly upper 70s and lower 80s, about 5 degrees above
normal for this time of year. It will remain a touch humid through
the day with dew points remaining in the 60s.
For tonight skies will be clear with the winds remaining light. Some
guidance suggests a light W wind, but winds will likely be variable
in direction with the weak pressure gradient remaining intact.
Another fairly mild night with lows primarily in the 60s close to
and in the metro and in the more urban areas, otherwise mainly upper
half of the 50s.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Friday will feature plenty of sunshine and remaining warm and a
touch humid. Temperatures will average a good 5 to 8 degrees above
normal with mainly upper 70s to middle 80s. A cold front is expected
to swing through out of the NW, but the front is expected to move
through dry. Dewpoints are not expected to drop until the afternoon
across mainly NW portions of the CWA as less humid air will trail
the front some. The more noticeable air mass change will be felt
Friday night into Saturday morning fall through the 50s, and some
40s dew points being indicated by all MOS / NBM guidance. Minimum
temperatures for early Saturday morning should fall down into 50s
for much of the coast, near 60 for the metro, but close to 50 well
inland to the N and NW. It appears that the winds will stay up
enough to preclude more in the way of radiational cooling. If the
winds out of the NE are overdone then temperatures may fall further
into the 40s for the interior locations. High pressure then moves
directly over the area later Saturday into Saturday night as the
pressure gradient decreases. Temperatures with the cooler airmass in
place should be about 10 degrees or so cooler during the day
Saturday compared to the previous day. With lighter winds Saturday
night temperatures may be a few degrees cooler than the previous
night with mainly upper 40s in the coolest spots, and 50s to around
60 elsewhere with the dry conditions lasting into the weekend.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Key Points:
*A noticeably cooler air mass arrives this weekend.
*Temperatures will be slightly below normal this weekend, but
trend warmer, especially towards the middle of next week.
*No precipitation is currently expected.
NBM primarily used during this forecast period.
Behind a cold front and high pressure prevailing the forecast will
remain dry. Highs will primarily in the lower 70s on Sunday with the
winds veering to the E/SE on Sunday as high pressure builds to the
east. Lows will generally be in the upper 40s to middle 50s, but
closer to 60 in and around the NYC metro.
Operational globals have varied solutions heading into next week
with how they handle Pac Jet energy moving in the PAC NW and western
Canada early next week. The 12Z GFS and 06Z ECMWF close off an upper
low over the Northern Plains by the middle of the week, while the
Canadian is much more progressive with a sheared out upper trough
approaching the eastern seaboard. The GEFs mean supports more
progression than the operational. For the time being, the western
periphery of the western Atlantic ridge looks to maintain enough
ridging to keep conditions mainly dry through the period. In
addition, a backing upper flow ahead of the troughing over the mid
section of the country will allow for a warmup through the middle of
next week. A frontal wave off the southeast coast on Monday does not
appear that it will impact the area.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Weak low pressure moves offshore today. A cold front approaches
tonight and moves across the terminals on Friday.
Improvements to VFR will continue this morning, but will take
longest to occur at KISP and KGON. Brief LIFR/VLIFR fog is
possible at SWF through 13z. VFR then prevails through Friday.
Light NE-N winds to start will shift to the NW-W through early
afternoon with afternoon SW sea breezes likely at coastal
terminals. Winds may remain W at KEWR and KTEB through late
afternoon before a light SE-S sea breeze develops. Winds will
veer to the SW after 00z and as speeds diminish to around 5 kt.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Brief MVFR ceilings possible at KJFK and KLGA through 13z.
Timing of sea breezes this afternoon could be off by 1-3 hours.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday through Monday: VFR.
&&
.MARINE...
Pockets of marginal small craft seas remain possible on the ocean
early today with primarily 4 ft seas, otherwise sub small craft
conditions should prevail. Seas will gradually lower tonight into
Friday. Ocean seas should average closer to 3 to 4 ft Saturday
morning with winds out of the NE getting to about 20 kt along with a
marginal small craft gusts possible, otherwise sub small craft
conditions should prevail through the weekend. Marginal small craft
seas are possible again towards Monday as ocean seas may get near 5
ft.
&&
.HYDROLOGY...
There are no hydrologic concerns through the entire forecast
period.
&&
.TIDES/COASTAL FLOODING...
With a subsiding ESE swell and generally weak offshore winds,
the rip current risk will be moderate for the beaches today,
and low for all beaches Friday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JE
NEAR TERM...JE
SHORT TERM...JE
LONG TERM...JE
AVIATION...DS
MARINE...JE
HYDROLOGY...JE
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion