Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service New York New York
1255 PM EST Monday Nov 30 2015

strong high pressure will build east across New England
today...then slowly retreat east out into the North Atlantic
tonight. Low pressure along an approaching warm front will pass
to the south and east Tuesday into Tuesday night. A cold front
will then pass through on Wednesday. High pressure will then
build in for the end of the week into the weekend.


Near term /until 6 PM this evening/...
scattered to broken stratocu today as moisture pools under a
strong subsidence inversion. Temperatures will be on the cool
side...rising to only the Lower/Middle 40s.


Short term /6 PM this evening through 6 PM Tuesday/...
big picture shows a split flow regime upstream...with a closed
low moving out of The Rockies into the plains states through
tonight. Upper ridging out ahead will quickly pass across this
evening...followed quickly by large scale warm air/moisture
advection aloft...and continued low level easterly flow as surface
high pressure retreats and as southern stream energy moving across
the Tennessee Valley toward the southern middle Atlantic coast induces surface
cyclogenesis just offshore. Operational models show enough lift
and low enough conditional pressure deficits at 295-300k layer to
enable precipitation to develop around or after midnight in NYC metropolitan and
the lower Hudson Valley...with chance pop for these areas and
likely toward daybreak for NYC and most of NE New Jersey.

Temperatures will be warming enough aloft to make falling precipitation all
liquid...but ultimately p-type will depend on surface temperatures at precipitation
onset. With some cold air damming remaining in place...temperatures could
be cold enough to allow for a period of light freezing rain...
especially if any early evening clearing of stratocu occurs just
after sunset...allowing for better radiational cooling before
higher clouds move in aloft...and/or if colder air drains down
into Orange County from the middle Hudson Valley. No hazards issued
at this time...but a Freezing Rain Advisory may eventually be needed for some
inland sections...mainly Orange County...and possibly for other
areas just to the southeast.

Lows tonight should range from the upper 20s in the valleys of
Orange the lower 30s across most of the
middle/upper 30s coastal the lower 40s in NYC.

Any early morning freezing rain should change to plain rain by
middle morning...with a steady light rain through the day. High temperatures
will be near 50 for NYC/Long Island...and in the 40s to the


Long term /Tuesday night through Monday/...
unsettled weather expected Tuesday night and Wednesday as complex
system impacts the area.

Initial area of low pressure along the warm front passes south and
east of Long Island Tuesday night. Aloft...ridge axis slides east as
upstream closed low/trough tracks across the Upper Middle west and
toward the Great Lakes region.

As this trough approaches...surface cold front and wave of low pressure
approaches Wednesday. Discarded quicker NAM solution as it is much
more progressive with handling of upper trough and surface front when
compared to GFS/gefs/ECMWF/ggem.

Will follow a blended model approach and expect timing of cold front
sometime around 00z Thursday...give or take a few hours.

Stratiform rain expected Tuesday night ahead of the warm front...then
will switch to convective wording...showers Wednesday ahead of the
cold front. Showers taper off between 00z and 06z Thursday.
Will cap probability of precipitation at likely or just under categorical for now...but
these probability of precipitation could very well be increased if subsequent model
runs support measurable quantitative precipitation forecast Tuesday night and Wednesday.

Upper trough passes across New England Thursday...and gusty northwest flow
prevails behind the cold front. Dry weather returns Thursday through
the weekend as high pressure builds.

Above normal temperatures Tuesday night and Wednesday will settle back closer
to seasonal averages Thursday through the weekend.


Aviation /18z Monday through Saturday/...
hi pressure over the region today will give way to low pressure passing S
of Long Island Tuesday.

Scattered-broken clouds around 2500-3500 feet today...becoming broken-overcast around
2000 feet tonight. Widespread MVFR overnight through Tuesday. Periods of IFR
possible Tuesday afternoon...mainly after 18z. Steadiest rain along and east of
a line from kjfk-klga-khpn after 16-18z Tuesday.

NE winds gradually veering to the east-northeast through this evening...then
remaining generally east-northeast through the day Tuesday. In the extended
tafs...there could be a shift to the north-northeast just before 00z Wednesday.

..NY 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: scattered-broken clouds today could result in
periods of both VFR and MVFR.

Klga fcster comments: scattered-broken clouds today will result in periods
of both VFR and MVFR.

Kewr fcster comments: scattered-broken clouds today will result in periods
of both VFR and MVFR.

Kteb fcster comments: scattered-broken clouds today could result in
periods of both VFR and MVFR.

Khpn fcster comments: scattered-broken clouds today could result in
periods of both VFR and MVFR.

Kisp fcster comments: scattered-broken clouds today will result in periods
of both VFR and MVFR.

Outlook for 18z Tuesday through Saturday...
rest of Tuesday...MVFR or lower with east winds becoming vrb overnight.
Wednesday...MVFR or lower with southerly flow.
Wednesday night...possible improvement to VFR by 12z Thursday. Winds shifting
to the west.
Thursday...VFR. West-northwest flow 10-20kt.
Friday...VFR. West flow 10-20kt.
Sat...VFR. Winds shifting to the north.


Small Craft Advisory conds this way to a lull this
afternoon/evening...then Small Craft Advisory conds should return late tonight into
Tuesday as east-NE winds increase between low pressure approaching from
off southern middle Atlantic coast and retreating strong high
pressure. If the low is stronger and/or tracks closer to the area
on Tuesday...the ocean waters could experience a period of minimal gales.
No gale watch/warning issued yet due to forecast uncertainty.

Easterly flow Tuesday night will lighten as an area of low pressure
passes to the east. As a warm front remains in the vicinity late Tuesday
night into Wednesday...winds may vary as they continue to lighten.
S/SW winds ahead of a cold front are expected Wednesday afternoon.
Then...gusty northwest winds prevail behind the cold front Wednesday night and
Thursday. Winds lighten Thursday night and Friday as high pressure builds
from the west.

Per wave watch...rough ocean seas Tuesday night due to the initially
strong easterly winds will subside Wednesday before building again
behind the cold front Wednesday night into Thursday. These seas do subside
once again late Thursday through Friday as the winds diminish.


quantitative precipitation forecast of around an inch Tue-Wed. Most of this should fall from late
Tuesday night into Wednesday evening. No flooding issues anticipated.


Okx watches/warnings/advisories...
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until 6 am EST Wednesday for anz350-353-


near term...Goodman
short term...Goodman
long term...precipitable water

National Weather Service Glossary of Abbreviations