Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 061826
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
126 PM EST Tue Dec 6 2016

.SYNOPSIS...
High pressure shifts east this afternoon. Low pressure will track
off of Cape Hatteras tonight, and southeast of Long Island and out
to sea on Wednesday. A series of cold fronts will move southeast
across the region through Friday followed by cold canadian high
pressure Saturday Low pressure will approach Sunday and move
across the area early next week.

&&

.NEAR TERM /UNTIL 3 PM THIS AFTERNOON/...
Clouds will continue to lower and thicken this afternoon as high
pressure shifts to the east. There could be a late day shower in
the vicinity of the city and NE NJ. Temps should be able to warm
another degree or two. Adjusted the high temp forecast over the
southern zones accordingly.

&&

.SHORT TERM /3 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/...
Low pressure will develop along a warm front late today over the
Southeast, with the low deepening off of Cape Hatteras by around
00Z. The low will then hook to the right after 6Z and track out to
sea.

The NAM, GFS and ECMWF were tightly clustered on the track and
intensity of the low.

The thermal profiles progged are minimally supportive of snow
with the system. This quickly eliminates the coasts from snow
chances with a mild boundary layer on easterly component flow.
Across the interior, any accumulating snow will depend on wet
bulbing and elevation. As a result, only minor snow amounts are
expected for the majority of the forecast area at this time.

The main exception is across Orange county, where it appears they
are far enough inland to avoid a marine influenced boundary layer,
have enough deep lift to produce moderate precipitation rates and
maximize the wet bulb effect, and have some elevation to cool the
low levels orographically. Because of this, a Winter Weather
Advisory has been issued for the county. Much of the area could
only see a slushy inch or so, but elevations over a thousand feet
could pick up around 4 inches if everything comes together as
currently forecast.

As the lift weakens after 6Z and dry air aloft spills in, the
precipitation looks to transition to light rain and drizzle early
Wednesday morning into the early afternoon. There is a low chance
that some pockets of freezing drizzle develop across the interior
before 12Z. The most likely spot is where the advisory has already
been issued for snow.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Little change in the long term as a closed upper low remain
across southeastern Canada Wednesday night through Friday. A
shortwave will rotate around the closed low bringing a cold front
and surface trough moving through the Mid Atlantic Thursday. This
may result in isolated to scattered rain/snow showers, along with
a cold air mass. This cold front will bring temperatures around 5
to 10 degrees below normal by the end of the week.

The upper low opens and moves out late Friday and Friday night with
weak upper ridging. The upper flow become nearly zonal across the
continental United States Friday night and through the weekend.
With high pressure moving off the northeast coast Sunday a return
flow develops and warm advection sets up into Monday.

The next shortwave to affect the area will move on shore of the
Pacific northwest Friday night and quickly move across the country.
Cyclogenesis occurs across the central plains Sunday into Sunday
night with the low tracking through the Great Lakes. Precipitation
Sunday night may start as snow inland and transition to rain Monday
and will be dependent on how quickly the warmer air moves into the
area. If a warmer layer moves in aloft before the low level cold air
is scoured out there will be a chance for some freezing rain Sunday
night. With the uncertainty did not include in the forecast at this
time and leaned toward a warmer solution.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
High pressure will move offshore giving way to low pressure
approaching which will pass southeast of the area tonight. VFR
expected for the rest of the afternoon and then MVFR/IFR
thereafter with rain moving in tonight. The rain becomes more of a
drizzle overnight into early Wednesday and then some lingering low
level clouds/patchy fog persist for Wednesday. There is some snow
expected inland tonight with KSWF expecting to receive a period of
light accumulating snow of a few inches.

Winds are becoming more easterly near 10 kt with gusts expected to
develop between 15-20 kt tonight, mainly for coastal terminals.
Winds become light Wednesday morning and into the early afternoon
Wednesday with varying directions.

Overall confidence with the forecast lowers tonight and even more
for Wednesday because of the low confidence in wind direction
forecast for Wednesday morning into afternoon. Timing of MVFR/IFR
conditions could be 2-3 hours off from forecast.

     NY 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: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

KLGA TAF Comments: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

KEWR TAF Comments: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

KTEB TAF Comments: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

KHPN TAF Comments: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

KISP TAF Comments: Some occasional IFR conditions will be possible
this evening. Gusts at times could be a few kts higher than
forecast.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Wednesday afternoon...MVFR improving to VFR with more westerly
flow developing. IFR possible in the afternoon.
.Wednesday night-Thursday night...Mainly VFR.
.Friday-Friday night...VFR. NW winds 15-20 kt, gusts up to 25 kt
day through evening.
.Saturday-Sunday...Mainly VFR.

&&

.MARINE...
Northeast to east winds this afternoon, intensifying tonight. A
Small Craft Advisory has been issued for the ocean tonight into
Wednesday for this, with an advisory for the Harbor for tonight.
Elsewhere, winds and seas area expected to remain below small
craft levels.

Winds and seas will remain below SCA levels Wednesday night
through Thursday as low pressure remains to the north across
southeastern Canada. A cold front will move through Thursday and a
strong and gusty northwest flow will develops. Thursday night SCA
gusts develop on the ocean waters, and then during Friday winds
increase, to near gale force on the ocean waters, and SCA gusts on
the remainder of the forecast waters. SCA gusts continue into Friday
night, then subside late as high pressure begins to build to the
west. Saturday morning winds and seas are expected to be below SCA
levels on all the waters as high pressure continues to build. Winds
and seas increase once again early next week as another low pressure
system moves across the area.

&&

.HYDROLOGY...
A half inch or less of liquid equivalent is expected tonight.
Otherwise, no hydrologic impacts are anticipated the next 7 days.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Weather Advisory from 6 PM this evening to 6 AM EST
     Wednesday for NYZ067.
NJ...None.
MARINE...Small Craft Advisory from 6 PM this evening to noon EST
     Wednesday for ANZ350-353-355.
     Small Craft Advisory from 6 PM this evening to 6 AM EST
     Wednesday for ANZ338.

&&

$$
SYNOPSIS...BC/JMC
NEAR TERM...JMC/JC
SHORT TERM...JMC
LONG TERM...BC
AVIATION...JM
MARINE...BC/JMC/JC
HYDROLOGY...BC/JMC



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