Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
353 PM EST Tuesday Nov 24 2015
Canadian high pressure builds in through tonight...then slowly
slides to the east through Friday. A weak low pressure trough will
develop along the middle Atlantic coast on Thanksgiving day as the
high retreats. A cold front will approach from the west on
Friday and pass through on Saturday...followed by high pressure
building in for the rest of the weekend. A warm front will slowly
approach from late Sunday night into Tuesday.
Near term /through Wednesday/...
cloud cover continues to decrease overnight amidst subsidence in
the wake of this morning's short wave trough. Confluence aloft
will aid in the strengthening of the surface high that will build
across the area tonight...decreasing already light winds further.
The combination of clear skies and light winds will create
favorable conditions for radiational cooling...with temperatures
expected to be near or slightly below climatological normals.
Little cloud cover is expected for Wednesday...with temperatures
rising to near normal values.
Short term /Wednesday night/...
as high pressure moves east of the area...onshore flow will return
with a subtle increase in moisture, particularly below 6000 ft,
expected. The NAM is an outlier with how quickly moisture returns
to the area and suggests drizzle will be possible for Wednesday
night. Given the antecedent dry conditions...currently expecting
any drizzle to be delayed until Thursday morning at the earliest.
Long term /Thursday through Tuesday/...
as the core of the high passes south of Nova Scotia...a weak
inverted trough will develop along the middle Atlantic coast and up
into the local area...helping focus 800 mb-9 moisture beneath a
subsidence inversion and provide enough low level
convergence/lift to make Thanksgiving day a mostly cloudy
day...with some potential for light rain or drizzle. Multiple
models have been signaling this for over a day now...but kept
measurable precipitation chances low...in the 20-30 percent range...since
the GFS also overplayed a similar event back on Nov 18th...where
broken-overcast stratocu but little if any precipitation did develop. Daytime
heating should bring a break in these conditions west of the
Hudson Thursday afternoon...then clouds should return throughout Thursday
night via cooling beneath the inversion...and last into Friday
morning. Thursday will be relatively mild despite cloud cover and
precipitation...with highs ranging from 55-60.
Friday looks dry and mild...with temperatures on the high side of guidance
and ranging from 60-65. The front will be slow to approach Friday
night...with chances for showers late at night and into Sat
morning. Dry colder weather will follow for Sat afternoon into
Sunday...with highs in the 40s to near 50s...and lows in the upper
20s and 30s.
Models continue to trend north/west with a closed low ejecting out
of the SW states this weekend..and heading toward the Great Lakes
on Tuesday. Most of the associated light precipitation with its leading warm
front should be in the form of rain...but with potential for low
level cold air damming at precipitation onset as high pressure moves
east...precipitation type at onset may not necessarily be in the form of
rain well inland late Sunday night into Monday morning.
Aviation /20z Tuesday through Sunday/...
high pressure will be over the terminals today and
tonight..providing VFR conditions.
A weak shortwave will exit the region this evening with decreasing
West winds winds veer to north tonight...NE Wednesday morning...and then southeast
... Metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts
can be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: no unscheduled amendments expected.
Klga fcster comments: no unscheduled amendments expected.
Kewr fcster comments: no unscheduled amendments expected.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 18z Wednesday through Sunday...
Wednesday night-Thursday night...chance of MVFR or lower ceilings.
Friday-Saturday...mostly VFR. MVFR ceilings possible in showers
Friday night into Saturday.
Sunday...chance of sub-VFR in rain late.
winds will remain 10kt or less on all waters through Wednesday.
Mainly sub-advisory conditions will continue through Friday with a
weak pressure gradient.
Small Craft Advisory conds may be possible on the ocean Friday night into Sat...first
via incoming swells generated by the pressure gradient between a
sprawling high pressure system along the coast and over the
waters...and a subtropical low or trough near Bermuda. Maximum wave
heights may reach 6-7 feet on Sat. Wind gusts in northerly flow
after a cold frontal passage on say may also reach 25 knots.
dry through Wednesday. Light drizzle possible Thursday with
minimal accumulations. A cold frontal passage Friday night into
Saturday may bring light precipitation (less than 1/4 inch).
water levels are expected to remain below minor flooding
benchmarks at high tide Wednesday morning.