Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 162344
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
744 PM EDT Tue Oct 16 2018

.SYNOPSIS...
High pressure over the region weakens tonight. A cold front then
approaches on Wednesday and passes through during the late day to
early evening hours. High pressure then builds to the southwest,
then south of the Tri-State through Friday. A cold front
approaches Friday night, then crosses the area on Saturday,
followed by yet another high building to the southwest and south
through Monday night. A warm front crosses the area next
Tuesday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Quick update to speed up the eve temp drop. Otherwise the fcst
was on track. A zonal flow aloft will continue tonight with weak
high pressure over the area. Dry weather continues with some
cirrus moving through. Lows ranging from the upper 40s in the
city to the mid 30s in some of the outlying suburbs. Can`t rule
out patchy frost for some these colder spots, but without the
likelihood of a clear sky and calm winds, will not include it in
the forecast at this time.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
The upper patten amplifies with a longwave trough axis approaching
the region and passing through Wednesday night. An attendant cold
front moves through during the late-day/early evening hours.
Moisture with the front isn`t very deep, but enough to warrant low
chances of showers north and west of the city during the
afternoon/early evening.

A tightening pressure gradient and cold air advection will bring
increasing winds and gusts Wednesday night. The wind will prevent
radiational cooling, however the cold air advection will still
manage to knock the temperatures down into the low-mid 30s across
the northern suburbs. Lows in the mid and upper 30s are expected for
most other spots, with the city averaging around 40.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Deep layered ridging builds over the area Thursday and Thursday
night, with its axis sliding offshore on Friday. There should
be sufficient subsidence under the ridge to have minimal cloud
cover and dry conditions during this time frame. Low level cold
advection on Thursday will limit highs to 10 to 15 degrees below
normal - with temperatures mainly from the lower 40s to around
50 across the region.

Lows on Thursday night will run around 5 to 10 degrees below
normal. Interior portions of the lower Hudson Valley and S CT
could see lows around freezing for the first time this fall. If
trends hold, Freeze Watches and possibly warnings could be
needed for at least parts of that area.

SW flow setting up in the afternoon should allow temperatures
to moderate on Friday, but still should end up around 5 degrees
below normal.

A 700-500 hPa shortwave and associated vorticity maxima
approach from the west Friday night and cross the area on
Saturday. There should be sufficient lift for scattered showers
across most of the region ahead of this feature - mainly late
Friday night/Saturday morning.

A full latitude trough then builds in Saturday night and
Sunday. Have slight chance pops only on Saturday night with the
best dynamics. For now have gone dry on Sunday, but depending on
exactly how cold the low level cold pool is, could end up with
some isolated showers/sprinkles.

Northern stream shortwave ridging builds over the area Sunday
night, followed by a northern stream shortwave trough passing to
the north on Monday. Associated subsidence should keep things
dry Sunday night, and the best dynamics should stay far enough
to the north, that when coupled with dry low levels, Monday
should be dry as well.

Continue to have fast flow aloft Monday night-Tuesday as the
region remains on the southern periphery of a northern stream
long wave trough. For now it appears that the low levels should
be too dry to support any precipitation, however with passing
shortwaves progged and low level warm advection do introduce
slight chance pops from N to S late Monday night and Tuesday. It
could be cold enough late Monday night, that if there is any
precipitation well NW of NYC, it could be possibly mixed with
snow.

Temperatures should be above normal Friday night and near normal
Saturday. Temperatures should then be below normal through
Tuesday.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR as high pressure builds to the south tonight, followed by a
cold frontal passage on Wed. W winds will start to increase
ahead of fropa by 13Z-14Z, then veer WNW and gust either side of
30 kt after 18Z. Peak wind gusts could be a few kt higher than
prevailing fcst.

 ...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: Peak wind G35KT possible 20Z-23Z.

KLGA TAF Comments: Peak wind G35KT possible 20Z-23Z.

KEWR TAF Comments: Peak wind G35KT possible 20Z-23Z.

KTEB TAF Comments: Peak wind G30-35KT possible 20Z-23Z.

KHPN TAF Comments: Peak wind G35KT possible 20Z-23Z.

KISP TAF Comments: Peak wind G30-35KT possible 20Z-23Z.

.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.Wednesday night...Mainly VFR. NW winds 15-20G25-30KT. Highest
winds in the evening.
.Thursday...VFR. NW winds 10-15G20-25KT.
.Friday...VFR.
.Saturday...Chance of showers and accompanying MVFR conds. SW
winds 10-15G20KT.
.Sunday...VFR. W-NW winds G15-20KT.

&&

.MARINE...
High pressures drifts into the Atlantic tonight, and winds and seas
will remain below SCA levels through this evening. Ocean winds and
seas increase late at night as the pressure gradient begins to
tighten ahead of an approaching cold front. A SCA is therefore in
effect overnight for the ocean. SCA conds then spread to the rest of
the waters Wednesday afternoon as the cold front nears. The front
moves through late afternoon/early evening with winds increasing and
becoming more gusty with a tight pressure gradient and cold air
advection.

Gale conditions should continue on the coastal ocean waters
east of Fire Island Inlet into Thursday. However, at this time,
there is not sufficient confidence to extend the gale warning
into Thursday at this time. On the remainder of the waters Small
Craft Advisory (SCA) conditions are expected on Thursday. SCA
conditions then linger into/through Thursday night. Most waters
should have a respite from SCA conditions on Friday, though
cannot rule out 25 kt gusts on the coastal ocean waters E of
Moriches inlet.

SCA conditions then return to all but NY harbor and W Long
Island Sound Friday night and Saturday and possibly into Sunday
- with gusts around 25 kt possible through the weekend.

&&

.HYDROLOGY...
No widespread significant hydrologic issues are expected
through next Tuesday.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from noon to 6 PM EDT Wednesday for
     ANZ330-335-338-340-345.
     Gale Warning from 6 PM Wednesday to 6 AM EDT Thursday for
     ANZ330-335-338-340-345-350-353-355.
     Small Craft Advisory from midnight tonight to 6 PM EDT
     Wednesday for ANZ350-353-355.

&&

$$
SYNOPSIS...JC/Maloit
NEAR TERM...JMC/JC
SHORT TERM...JC
LONG TERM...Maloit
AVIATION...Goodman
MARINE...JC/Maloit
HYDROLOGY...JC/Maloit
EQUIPMENT...


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