Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 230134
Area Forecast Discussion
National Weather Service New York NY
934 PM EDT Sat Oct 22 2016
Deepening low pressure moves through Maine and southeastern
Canada through Sunday. Another cold front associated with the low
moves through the area late Sunday night into early Monday
morning. Canadian high pressure builds behind the front Monday
through Wednesday. Low pressure approaches and moves across the
area Thursday into Friday.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Deepening low pressure over central Maine will continue to move
north into southeastern Canada overnight, reaching as low as 978
MB by Sunday morning. Trends show drier air advecting in, and any
lingering rain should lift north of the area as the night
progresses. Expected rain to end around 06-08Z as the last of the
vorts rotates through the trough. Weak cold advection also
continues and with low level winds to around 40 to 50 KTs. Still
expect some of these winds to mix to the surface, although sfc
cooling should prevent frequent gusts of 40 kt. With the best
mixing through this evening there is still the potential for gusts
and perhaps some sustained winds to reach wind advisory criteria.
Largest pressure rises continue across cstl zones.
As such, will maintain the advisory for Nassau county and the NYC
zones until 04z, and continue through 10Z for the remainder of
the zones that were in the advisory, mainly eastern zones.
Temps will fall slowly or remain steady in this mixed environment.
Weak CAA and some clearing will allow for temp falls of a few
degrees later tonight.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday is expected to be dry with the upper trough remaining and
the upper low beginning to cut off. Gusty winds remain however low
level winds will be diminishing and cold advection shuts off 09Z
to 12z and weak warm advection starts. Winds early in the morning
will be the strongest and an occasional gust may approach 45 MPH
across the eastern zones before winds diminish.
A northern stream shortwave moves quickly through the northern
tier of the United States and moves into the upper trough Sunday
evening. A re enforcing cold front and the shortwave then move
through 06Z to 12Z Monday with a chance of showers. With minimal
lift will have only chance probabilities.
.LONG TERM /MONDAY THROUGH SATURDAY/...
Upper trough remains across the northeastern portion of the country
early to mid week, as ridge to the west eventually flattens per
global models. Differences arrive with handling of shortwave that
develops across the upper mid west as it traverses east late in the
At the surface, low pressure associated with lingering upper trough
moves slowly across eastern Canada, as high pressure builds out of
central Canada and into the Great Lakes Region through mid week. The
high briefly slides across the area Thursday before giving way to
low pressure Thursday and Friday. Frontal boundaries, first warm
front followed by the cold front, impact the area from late
Thursday, into Friday. For Saturday, forecast becomes less clear. A
possible weak frontal boundary may move through Saturday, but
confidence in this remains low at this time.
Generally dry conditions are anticipated Monday through Wednesday
night as initial shortwave and front clears the area, and high
pressure slowly builds. Cyclonic flow could result in more cloud
cover each day, especially into New England Tuesday and possibly
The best chance for rain looks to be late Thursday, Thursday night
into Friday. ECMWF slower with upstream system compared to usually
Temperatures will initially average right around normal Monday. Then
cooler canadian air settles in and expect readings to remain below
normal Tuesday and Wednesday.
Temperatures slowly moderate closer to normal Thursday through
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --Strong low pressure will move slowly north into Quebec over the
next 24 hours. As it does so, any lingering light rain and MVFR
cigs, mainly at/near KGON and KSWF, will give way to VFR
W winds 15-20 kt with gusts 25-30 kt, with an occasional higher
gusts 30-35 kt, are still ongoing this evening. These winds should
diminish a few kt overnight, and the resume by 13Z-14Z Sunday.
These winds should diminish during Sunday afternoon, with exact
timing and degree still a little uncertain.
.Outlook for 00Z Monday through Thursday...
.Sunday night-Monday Morning...Mainly VFR. Chance of showers
.Monday Afternoon-Tuesday...VFR. NW winds G20-25KT.
-- End Changed Discussion --
Deepening low pressure continues to track slowly to the north
across Maine and into southeastern Canada through Sunday night.
Winds and gusts have increased and gale conditions are observed
this evening. As the low continues to deepen and with cold
advection continuing into Sunday morning, gale conditions will
continue. The winds and gusts will begin to gradually diminish
late Sunday morning into Sunday afternoon. Gale conditions may end
by Sunday afternoon across NY harbor and the western Long Island
Sound. Will leave gale warning posted across all the forecast
waters through Sunday.
Gusty NW winds 25-30 kt are likely Monday through Tuesday as the
pressure gradient remains rather tight. Winds and seas are forecast
to decrease on Wednesday and into Thursday as high pressure builds.
Little additional QPF is expected for the remainder of the
evening. Dry late tonight through Sunday evening. For Sunday
night, around a tenth of an inch of rainfall is possible.
Rainfall amounts of 1/2 inch or more are possible Thursday into
Friday. No hydrologic impacts are anticipated.
CT...Wind Advisory until 6 AM EDT Sunday for CTZ007-008-011-012.
NY...Wind Advisory until 6 AM EDT Sunday for NYZ078>081.
Wind Advisory until midnight EDT tonight for NYZ072>075-
MARINE...Gale Warning until 6 PM EDT Sunday for ANZ330-335-338-340-345-