Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 251711
Area Forecast Discussion
National Weather Service New York NY
111 PM EDT Tue Oct 25 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.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Updated forecast to account from stratocu in the NW flow moving
across the area. Deep-layered cyclonic flow appears to be
providing enough lift to maintain the clouds even in a subsident
NW flow. Highs have also been nudged down a degree or two in many
The upper level trough will move east into the Canadian Maritimes
today with a shortwave going through the region around the base of
High pressure centered in Ontario builds slowly southeastward.
Gusty NW winds up to mph winds continue due to a tight pressure
gradient and well mixed airmass.
-- End Changed Discussion --
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The center of the high tracks to southeast Ontario and continues to
build into the local region tonight. There will be some slight
ridging aloft. The winds will become lighter in response to a
weaker pressure gradient. The cooler airmass will already be
within the region. The closer proximity of the high will result in
more subsidence and less clouds. The combination of factors will
lead to better efficiency of radiational cooling especially across
the interior. Freezing temperatures expected across much of the
interior where freeze warning is in effect.
Used MAV guidance for lows tonight which will range mainly
between 30 and 40.
For Wednesday, the high pressure center moves east into Quebec
with a continued decrease in pressure gradient across the local
region. Winds will be lighter but will still be a little breezy
from diurnal heating and inherent mixing. The cold air advection
at 850mb decreases as the weather pattern shifts. Cyclonic flow
aloft lessens as the upper level low in the Canadian Maritimes
shifts east while across the local region, there will be some
slight ridging aloft. Model guidance in pretty good agreement with
a downward trend in temperatures Wednesday as highs will be a few
degrees cooler than the previous day.
Used a blend of MET/MAV/ECS guidance for highs Wednesday which
will range from the upper 40s to lower 50s.
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A shortwave moving across the Great Lakes region late Wednesday
night into Thursday morning, will slowly move east, passing
across the local area Thursday night.
At the surface, high pressure continues to slide east as a warm
front approaches from the west as low pressure tracks across the
Great Lakes and across PA/western NY.
Warm air advection rain 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 light snow briefly NW
zones. Some accumulations are possible across higher elevations
before a change to plain rain occurs.
Rain is expected through thursday night, before ending during the
day on Friday. There is a chance some lingering rain showers could
continue into the afternoon across the eastern half of the CWA.
High pressure builds to the south as another low moves across the
Great Lakes Region Saturday, passing to the north early Sunday.
Drier weather returns for the start of next week.
Temperatures through the long term will remain slightly below or
right around normal.
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
VFR as high pressure builds over the region.
NW flow today with winds near 310 magnetic most of the day.
Increasing cloud cover may limit gusts slightly, so have made
minor adjustments in the 16Z amendments.
...NY Metro Enhanced Aviation Weather Support...
Detailed information...including hourly TAF wind component fcsts
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: Winds could be south of 310 magnetic at times
KLGA TAF Comments: Winds could be south of 310 magnetic at times
KEWR TAF Comments: Variability in wind direction and speed
possible through 18Z. Lighter flow will result in northerly wind
direction, with gusty flow producing winds around 300 magnetic.
The afternoon KEWR haze potential forecast is green...which
implies slant range visibility 7SM or greater outside of cloud.
KTEB TAF Comments: Gusts may only be occasional through 18Z.
KHPN TAF Comments: No unscheduled amendments are expected.
KISP TAF Comments: No unscheduled amendments are expected.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...VFR. NW-NNW G20KT possible near the coast.
.THU...MVFR conditions likely in rain. IFR conditions possible at
night. SE winds 10-20KT.
.FRI...VFR. W-NW winds G25-30KT.
.SAT...VFR. Chance of rain. SW winds G15-20KT.
-- Changed Discussion --SCA conditions continue on all waters this afternoon due to a
steep pressure gradient between a weak low in the Canadian
Maritimes and a strong high in Ontario.
For tonight, the pressure gradient weakens so gusts will decrease
likewise. SCA conditions will keep up across the ocean while non-
ocean waters will subside below SCA during the evening after 00Z.
For Wednesday, the pressure gradient is weak enough to
keep conditions below SCA on all waters.
Sub-SCA conditions are expected Wednesday night through much of
SW flow increases to 15-20 kt Thursday night out ahead of a frontal
system which should push ocean seas up to 5-6 ft. 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 frontal system Saturday into Sunday.
-- End Changed Discussion --
Dry weather remains 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 Warning from 2 AM to 9 AM EDT Wednesday for CTZ005>008.
NY...Freeze Warning from 2 AM to 9 AM EDT Wednesday for NYZ068>070.
NJ...Freeze Warning from 2 AM to 9 AM EDT Wednesday for NJZ002-004-
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ330-
Small Craft Advisory until 6 AM EDT Wednesday for ANZ350-353-