Area Forecast Discussion
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FXUS61 KOKX 231443
Area Forecast Discussion
National Weather Service New York NY
1043 AM EDT Sun Oct 23 2016
Low pressure over southeastern Canada will gradually weaken over
the next couple of days, while a clipper low and its associated
cold front move through the area early Monday morning. High
pressure builds across the area Tuesday and Wednesday, followed by
a Pacific frontal system at the end of the week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Surface low pressure centered near the St Lawrence river will
meander across southeastern Canada through today and into tonight
as the upper closed low and negative trough remain across eastern
Canada. The area remains in a gusty westerly flow through today
with mixing up to 850 MB will see gusts in 25 to 30 KT range most
of the day, especially into early this afternoon. With a well
mixed boundary layer across the region temperatures will be fairly
uniform...upper 50s to lower 60s.
Drier air and weak subsidence will keep area cloud free until
later this afternoon as clouds approach ahead of a shortwave
moving through the northern stream.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Northern stream shortwave moves quickly east tonight and passes
through the area after midnight. Decent lift along and ahead of
the associated mid level short wave will result in a brief period
of rain with up to a quarter inch possible. Most locations will
dry out by daybreak Monday with the possible exception of far
eastern LI and SE CT.
Cold advection will follow through the day Monday with another
shot of cold air following a short wave trough Monday evening.
Amplifying upper ridge over the western U.S. ahead of the next
Pacific storm system will help to amplify the downstream trough
across eastern Canada and the northeast. In addition, an upstream
block resides across the central Atlantic. This will result in a
deep-layered NW flow across the area with a shot of unseasonably
cold air to arrive Monday night and persist into mid week.
Gusty northwest winds will continue during this time with weakening
low pressure over eastern Canada and polar high pressure building
southeast from central Canada.
.LONG TERM /MONDAY NIGHT 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 through Wednesday night
as high pressure slowly builds. Cyclonic flow could result in
more cloud cover each day, especially into New England Tuesday and
The best chance for rain looks to be late Thursday, Thursday night
into Friday. ECMWF slower with upstream system compared to usually
Temperatures will be below normal Tuesday and Wednesday, then slowly
moderate closer to normal Thursday through Saturday.
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
High pressure builds to the south today with strong low pressure
over eastern Canada. A cold front moves through tonight into early
Gusty WNW winds continue today. Gusts 25-30 kt expected through
the late afternoon. A peak gust up to 35 kt cannot be ruled out,
but this will not be a frequent occurrence. Winds and gusts
diminish this evening, with winds backing to the SW around 7-10
VFR through the TAF period. There is a low chance for MVFR in
light rain late tonight into early monday morning.
.Outlook for 12Z Monday through Thursday...
.Monday Morning...Mainly VFR. Low chance for MVFR in light rain
early. Gusty SW-NW flow.
.Monday Afternoon-Tuesday Night...VFR. NW winds G20-25KT. Winds
diminish Tuesday night.
Little change to the winds, gusts and seas across the forecast
waters through today.
On the synoptic scale, a steep pressure gradient remains across
the waters between deep low pressure meandering across
southeastern Canada and high pressure centered across the
southeastern states. This will keep gales across all waters
especially with mixing depth increasing this morning into this
The pressure gradient weakens tonight with a clipper type low
passing through the area. The result will be wind gusts becoming
more occasional and diminishing. SCA conditions will be likely early
in the evening, but will eventually just be confined to the ocean
waters. However, after the associated cold frontal passage, winds
will resume gusting. Again, SCA conditions will be probable across
much of the waters for Monday through Tuesday. Winds diminish again
with a more substantial decrease of the pressure gradient Tuesday
night with a Canadian high approaching. High pressure remains
across the waters through early Thursday.
Up to a quarter inch of rain is possible tonight with a fast
moving area of low pressure. Rainfall of 1/2 inch or more is
possible Thursday into Friday. No hydrologic impacts are
MARINE...Gale Warning until 6 PM EDT this evening for ANZ330-335-338-