Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS61 KOKX 241933

Area Forecast Discussion
National Weather Service New York NY
333 PM EDT Mon Oct 24 2016

High pressure slowly builds in from southern Canada through
Wednesday. The high moves east on Wednesday giving way to a
frontal system Thursday into early Friday. Another frontal system
impacts the area this weekend, followed by high pressure Monday.


Daytime heating and moisture trapped below a subsidence inversion
around 800 hPa have allowed stratocumulus to continue to develop and
stream across much of the area this afternoon. With loss of heating
tonight, these clouds should diminish in coverage.
However, there could still be FEW-SCT coverage North and West of the
city. Sky conditions overall will be mostly clear overnight.

Strong pressure gradient will continue tonight between low pressure
across the Canadian Maritimes and High pressure building from
central Canada. This gradient will prevent winds from completely
decoupling and make it challenging for frost development where
temperatures fall into the middle 30s. A few rural interior
locations could see winds fall below 5 mph with temperatures
dropping to just above freezing. Another limiting factor on frost
development will be dew points falling into the upper 20s and lower
30s late tonight with increasing cold advection. Have continued with
patchy frost across portions of interior CT early Tuesday morning.

Lows will range from the middle and upper 30s inland to the lower
40s near the coast.


Upper trough over northern New England and the Canadian Maritimes
will slowly translate east Tuesday into Tuesday night. Cold
advection will continue with 850 temperatures dropping to -4 to
-6C. A similar subsidence inversion to Monday will likely be present
per BUFKIT soundings around 800 hPa. There appears to be enough
moisture during the day trapped beneath this inversion to help
develop some stratocumulus. Sky conditions start the day partly
cloudy, with the potential to go mostly cloudy at times in the
afternoon. Gusty NW winds are once again forecast from the strong
pressure gradient between the low to the northeast and building
high to the west. Mixing up to near 800 hPa should allow for
gusts 25 to 30 mph in the afternoon, strongest near the coast.

High temperatures will end up well below normal for this time of
year in the upper 40s and low 50s.

Cold advection continues Tuesday night, but ideal radiational
cooling conditions are not anticipated as winds will remain up.
However, the coldest airmass of the season will be in place and
temperatures should be able to fall to near 30 degrees across the
interior, and middle and upper 30s most elsewhere. Have therefore
issued a freeze watch across all of interior southern CT, the Lower
Hudson Valley excluding Orange county where the growing season has
ended, and interior NE NJ. Elsewhere, do not think a widespread
frost will occur due to the winds and overall dry airmass in


Trough finally departs, allowing weak ridge to briefly build

Next shortwave tracks across the Great Lakes Region Wednesday night,
and slows as it closes off Thursday and Thursday night over the
northeast. The pattern remains progressive as yet another shortwave
follows this weekend.

Some differences in the global models are noted with regard to
timing, and speed of these systems as they move west to east.

At the surface, high pressure builds overhead, then moves east late
Wednesday/Wednesday night. A warm front approaches Wednesday night
from the west as low pressure tracks across the Great Lakes and
across PA/western NY.

The low and associated frontal boundary slows as it moves over the
area Thursday, passing to the east Thursday night into Friday.

High pressure builds to the south as another low moves across the
Great Lakes Region Saturday, passing to the north early Sunday. Some
questions arise on Monday with upper levels, and thus surface
features at that time. Could be unsettled.

As for sensible weather, WAA showers move in late Wednesday night and
through the day Thursday. Enough cold air ahead of the WAA, and time
of day being early morning could result in some snow showers briefly
NW zones. Some accumulations are possible across higher elevations
before a change to plain rain occurs.

Once this area of showers moves east Thursday night, generally dry
weather is expected ahead of next best chance Saturday ahead of the
upstream shortwave.

After a chilly start to the period Wednesday, temperatures will be
near normal in this progressive pattern, with no large swings in
temperatures expected.


VFR this evening as high pressure builds over the region with a
gusty NW wind flow - gusts to around 25 KT through sunset, then

Very similar weather as today on Tuesday - VFR with NW SFC WND
G25 KT and cooler.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/

KJFK TAF Comments: Peak winds just under 30 KT thru sunset. Wind
direction will vary +/- 20 degrees of FCST, but average at or just
right of 310 magnetic.

KLGA TAF Comments: Peak winds in the upper 20s KT range thru sunset.
Wind direction will vary +/- 20 degrees of FCST, but average just
right of 310 magnetic.

KEWR TAF Comments: Peak winds in the upper 20s KT range thru sunset.
Wind direction will vary +/- 20 degrees of FCST, but average just
right of 310 magnetic.

KTEB TAF Comments: Peak wind gusts in the mid 20s KT range thru

KHPN TAF Comments: Peak wind gusts in the mid 20s KT range thru

KISP TAF Comments: Peak wind gusts in the upper 20s KT range  thru

.Outlook for 18Z Tuesday through Saturday...
.TUE AFTN...VFR. NW winds G25-30 KT, diminishing Tuesday night.
.WED...VFR. NW-NNW G20 KT possible near the coast.
.THU...MVFR possible IFR THU NGT in rain. SE SFC WND 10-20 KT.
.FRI...VFR. W-NW SFC WND gusts around 25 KT.


Strong pressure gradient over the waters will continue through
Tuesday with SCA conditions. Winds may briefly weaken on near
shore waters tonight before increasing again during the day on
Tuesday. The SCA remains in effect through Tuesday evening and may
need to be extended into Tuesday night on the ocean waters as
winds are likely to remain around 25 kt.

Gusty NW winds will diminish Wednesday as high pressure builds.
Winds shift around to the east, then SE Wednesday night as Thursday
as the high departs, and a warm front and low pressure system

As the low passes by Friday, winds shift back around to the west/nw
and increase behind the departing low. These winds back yet again to
the west/SW ahead of next low pressure system Saturday.

Ocean seas subside and remain well below 5 FT Wednesday, Wednesday
night and into Thursday. Seas build once again ahead of and behind
the low pressure system that impacts the waters later Thursday, and
these rough seas continue Friday night, then subside Saturday.

Dry weather is forecast through Wednesday.

Low pressure impacts the area Thursday and Thursday night. Forecast
QPF is expected to produce anywhere from 1/2 to 3/4 of an inch of
rainfall. Local amounts over an inch are possible. No hydrologic
impacts expected at this time.


CT...Freeze Watch from late Tuesday night through Wednesday morning
     for CTZ005>008.
NY...Freeze Watch from late Tuesday night through Wednesday morning
     for NYZ068>070.
NJ...Freeze Watch from late Tuesday night through Wednesday morning
     for NJZ002-004-103-105-107.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ330-335-338-


HYDROLOGY...DS/PW is the U.S. government's official web portal to all federal, state and local government web resources and services.