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Area forecast discussion 
National Weather Service New York New York
1029 am EST Mon Dec 5 2016

Synopsis...
an upper level disturbance and surface trough will pass east by
this afternoon. High pressure will build in on Tuesday. Low
pressure developing off the mid Atlantic coast Tuesday evening
will pass to the south on Wednesday. A series of cold fronts will
then move across from Thursday into Friday. High pressure will
build in on Saturday, followed by a warm front passing to the
north on Sunday.

&&

Near term /until noon today/...
trough has shifted to eastern CT/Long Island, with light precip to
its east. Sfc obs indicate most precip is now rain or a rain/snow
mix, though judging from mesonet obs and radar intensity, far
northern reaches of Middlesex and western New London in CT may
still be seeing all snow and some light accumulation on roads.

Farther west, winds have shifted WSW, and there may be partial
clearing in NYC Metro. Gusts up to 20 mph possible.

&&

Short term /noon today through 6 PM Tuesday/...
high pressure builds in from the west this afternoon, and over
the region late tonight into Tuesday morning. This will provide
dry weather and clearing skies. By Tuesday afternoon, low pressure
will be deepening near Cape Hatteras. The northern fringe of the
precipitation shield could reach the area by dark, so low chance
pop has been maintained, although the timing has been slowed from
the previous forecast based on the model consensus.

A blend of the guidance, which was in good agreement, was used
for temperatures through the period.

&&

Long term /Tuesday night through Sunday/...
a progressive upper flow across the lower 48 states will feature
a southern branch short wave trough ejecting out ahead of an
amplifying upper low over the upper Midwest and south central
Canada at the onset of the period. This will allow for surface low
pressure to pass off the mid Atlantic coast Tuesday night into
Wednesday, with a mainly rain event for the forecast area. The 00z
GFS continues to be warmer aloft versus the ECMWF/NAM. A
compromise of the two solutions results in some snow across far
northern sections of the lower Hudson Valley and interior SW
Connecticut, with the potential for 1-2 inches. This will depend
on how quickly the cold air erodes Tuesday night with high
pressure retreating to the NE. Elsewhere, it will be a rain event
with the up to half an inch possible.

A building upper ridge along the West Coast of North America
Wednesday into Thursday will allow the upper trough/low to dig southeast
across the Great Lakes and into the northeast states Thursday
into Friday. This will result in a series of cold fronts passing
through the area and an unseasonably cold air mass moving in for
Friday and the weekend. This will also be accompanied by strong
northwest winds Friday into early Saturday. Outside of some snow flurries
or sprinkles it will be primarily dry with scattered clouds,
mainly north and west of NYC. Warm advection on Sunday ahead of
low pressure moving into the Great Lakes may result in scatted
rain/snow showers.

&&

Aviation /15z Monday through Friday/...
a frontal system exits east of the region with a westerly flow
developing into this afternoon. High pressure builds in thereafter
through the rest of the taf period. West-northwest winds will become gusty
into this afternoon as well with gusts 15-20 kt. Winds diminish
going into tonight.

Conditions are beginning to improve across the region but there are
still some MVFR and localized IFR conditions. Light rain confined to
near kgon until this afternoon and it has exited all other
terminals. All locations are expected to improve to VFR by 17-19z.
Lower confidence with improvement timing and this could be off by an
hour.

... Metro enhanced aviation weather support...

Detailed information, including hourly taf wind component forecasts,
can be found at: http:/www.Weather.Gov/zny/n90

Kjfk taf comments: MVFR may not materialize before 17z. An
occasional higher gust than forecast is possible this afternoon.

Klga taf comments: an occasional higher gust than forecast is
possible this afternoon.

Kewr taf comments: IFR/MVFR end times could be an hour later than
forecast. An occasional higher gust than forecast is possible
this afternoon.

The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kteb taf comments: MVFR end times could be an hour later than
forecast. An occasional higher gust than forecast is
possible this afternoon.

Khpn taf comments: MVFR end times could be an hour later than
forecast. An occasional higher gust than forecast is possible this
afternoon.

Kisp taf comments: IFR/MVFR end times could be an hour later than
forecast. An occasional higher gust than forecast is
possible this afternoon.

Outlook for 15z Tuesday through Friday...
Tuesday...VFR early, then MVFR possible with a chance of light
rain or drizzle. Possible light snow inland late in the day.
Tuesday night-Wednesday...IFR in drizzle and light rain. Possible
light snow inland Tuesday night.
Thursday...MVFR possible with a chance of rain.
Friday...VFR. Northwest winds 15-20 kt, gusts 25-30 kt.

&&

Marine...
northwest flow will pick up this afternoon and evening behind a
passing trough, and an Small Craft Advisory is in effect beginning late this
afternoon for the ocean and eastern sound. Elsewhere, winds are
too marginal to issue an advisory at this time. Conditions should
improve late tonight and Tuesday as high pressure builds over
the waters.

As low pressure passes to the south Tuesday night into Friday,
marginal Small Craft Advisory conditions are possible, with east winds on the ocean
waters approaching 20 kt and seas around 5 ft.

Thursday into Thursday night another frontal system will move
through, with a strong cold passing through Thursday night.
Strong/gusty northwest winds will develop behind the front, with the
potential for gales Friday into Saturday morning on all waters.

&&

Hydrology...
no hydrologic impacts are anticipated the next 7 days.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory from 4 PM this afternoon to 6 am EST
Tuesday for anz330-350-353-355.

&&

$$
Synopsis...jmc/dw
near term...jmc/Goodman/dw
short term...jmc
long term...dw
aviation...jm
marine...jmc/Goodman/dw
hydrology...jmc/dw

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