-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 181109
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
609 AM EST Tue Dec 18 2018

.SYNOPSIS...
High pressure slowly builds in across the area into Wednesday
and shifts into the Western Atlantic by Thursday. This gives
way to an approaching and deepening area of low pressure from
the Southeast US Thursday night into Friday. The low continues
to strengthen and move northward across the Northeast west of
the Hudson Valley Friday through Friday night. For the weekend,
the low moves into the Canadian Maritimes and high pressure
builds in from the Southeast US. Weak low pressure approaches
close to the region for late this weekend into early next week
from the west.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High pressure builds in at the surface and aloft while a storm over
the Canadian Maritimes slowly shifts east. The combination of these
features will maintain a relatively tight pressure gradient over us
and bring us another breezy day. Sunny, but colder than normal
along with wind chills in the 20s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
The high pressure ridge axis approaches us tonight and shifts
through on Wednesday. Winds therefore diminish tonight and remain on
the lighter side through Wednesday night. Mostly clear conditions
expected through at least this evening, then varying amounts of over-
the-ridge cirrus are anticipated thereafter. Low temperatures
tonight below normal, then highs around normal on Wednesday.
Wednesday`s lows for the most part are expected to end up a little
above normal, however spots more prone to radiational cooling could
end up below normal if cirrus isn`t too prevalent.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Offshore high pressure based in the Western Atlantic Thursday will
eventually give way to approaching low pressure which will be the
focus of the long term. Winds will become more southeasterly. Mild
temperatures in the low to mid 40s are forecast for the day with
mainly dry conditions, although towards Northeast NJ, Lower Hudson
Valley and into NYC, POPs will increase in the afternoon for rain.

The main focus of the long term will be a developing mid latitude
cyclone moving along the Appalachians and up along the Hudson Valley
deepening from Thursday night through Friday night. The associated
warm front approaches Thursday night into early Friday and then
moves across during the day Friday. Rain becomes likely Thursday
night with categorical POPs late Thursday night through Friday
morning. There will be rising temperatures into the upper 40s to
lower 50s Thursday night with increasing warm and moist air
advection via strengthening southeasterly flow. This will be when a
strong low level jet, as conveyed by NAM and GFS Bufkit profiles to
be near 70kt in the 800-900mb layer. Strong inversion just above the
surface will limit gust potential on land with exception of any
heavy rain which could bring down the higher gusts of perhaps 40kt.

Rain could become heavy at times especially in the late Thursday
night through early Friday timeframe. Models show potential for
enhanced lift with deep omega appearing in this timeframe as well.

After the warm frontal passage, there will continue to be rain
showers and with elevated instability in the warm sector, there will
be a few thunderstorms possible as well. This will potentially
result in heavy rain. Max temperatures Friday are forecast in the
upper 50s. The region remains in the warm sector Friday night with
showers becoming more occasional in frequency and fog will be
possible as well with the moisture laden grounds and decreasing
winds. Min temperatures forecast Friday night are only in the low to
upper 40s.

For the weekend, low pressure moves northeast into the Canadian
Maritimes Saturday into Saturday night. A series of cold fronts pass
at the surface, one early Saturday and another one passing through
at night. Yet another cold front looks to move across late Sunday
night into Monday. Mainly dry conditions expected for the weekend
into early next week with just a slight chance of a shower Saturday
afternoon and late Sunday night. Temperatures return to closer to
normal values.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Strong low pressure near the Canadian Maritimes will slowly move
east as high pressure slowly builds from the west. The pressure
gradient between the two will support gusty NW winds, with
direction around 320 magnetic most sites, speeds 15-20 kt with
frequent gusts 25-30 kt most of today. A few peak gusts just
over 30 kt could occur this morning. Winds could be a little
higher than that at KISP/KGON from late morning into early
afternoon.

NW winds slowly diminish tonight.

...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: A few gusts close to 35 kt early.
The afternoon haze potential forecast is GREEN, which implies
slant range visibility P6SM outside of cloud.

KLGA TAF Comments: A few gusts close to 35 kt early.
The afternoon haze potential forecast is GREEN, which implies
slant range visibility P6SM outside of cloud.

KEWR TAF Comments: A few gusts close to 30 kt early.
The afternoon haze potential forecast is GREEN, which implies
slant range visibility P6SM outside of cloud.

KTEB TAF Comments: A few gusts close to 30 kt early.

KHPN TAF Comments: A few gusts close to 35 kt early.

KISP TAF Comments: A few gusts close to 35 kt early.

.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.Wednesday...VFR.
.Thursday...Rain with MVFR conds developing in the afternoon.
.Thursday night...Rain. MVFR conds in the evening. IFR conds, SE
winds 15G20kt and LLWS after midnight NYC metro/coast.
.Friday...Rain with IFR/LIFR conds. SE winds 20G25kt, LLWS, and
chance of a tstm in the morning NYC metro/coast. Warm fropa with
winds becoming S 10-15G20kt in the afternoon.
.Friday night...MVFR or lower conds with intermittent showers.
.Saturday...Mainly VFR. W winds G20-25kt.
-- End Changed Discussion --

&&

.MARINE...
Cold air advection along with a tight pressure gradient will likely
maintain gale force gusts on all waters at the start. Then as a high
pressure ridge approaches, winds and seas gradually diminish. End
times for the gale warning are unchanged for the time being, and SCA
conditions will follow. All waters should fall below advisory
criteria by Wednesday morning. Then as the center of high pressure
nears and passes through, tranquil conditions for Wednesday and
Wednesday night.

Gales possible on the waters late Thursday night into Friday with
any enhanced mixing from low level jet. Otherwise in terms of wind
gusts, forecast has below SCA winds Thursday into Thursday evening.
SCA level wind gusts late Thursday night on the ocean with all
waters having SCA level gusts Friday and then just the ocean Friday
night. SCA level gusts on all waters forecast for Saturday and
Saturday night. Seas are all below SCA Thursday into Thursday
evening and then late Thursday night, ocean is forecast to reach SCA
seas. The ocean pretty much stays in SCA range for seas for the rest
of the forecast period while non-ocean waters stay below SCA except
for Eastern Long Island Sound this weekend.

&&

.HYDROLOGY...
Widespread rain of 1.5 to 2 inches possible for late week with
locally higher amounts but still uncertainty in terms of amounts.
Minor flooding will be a possibility.

&&

.TIDES/COASTAL FLOODING...
Full moon coming up on December 22. Potential of widespread minor
coastal flooding with possible moderate coastal flooding
particularly for South Shore Bays Friday with piling water and
increasing SE flow. Surge of 1-2 ft needed for most locations to
reach coastal flood benchmarks. Possible coastal flooding but to a
lesser extent for Saturday.

&&

.EQUIPMENT...
NYC Central Park winds are out of service until further notice.
Loss of data is due to a severed cable. Parts are on order.

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

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until noon EST today for ANZ330-335-338-340-345.
     Gale Warning until 6 PM EST this evening for ANZ350-353-355.

&&

$$
SYNOPSIS...JC/JM
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JM
AVIATION...Goodman
MARINE...JC/JM
HYDROLOGY...JC/JM
TIDES/COASTAL FLOODING...
EQUIPMENT...