Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 192233
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
633 PM EDT Thu Oct 19 2017

.SYNOPSIS...
A weak cold frontal passage will occur late tonight. High
pressure will dominate from Friday through Monday, moving
offshore Sunday through Monday. A slow moving frontal system
will then approach the area Tuesday into Tuesday night with a
cold frontal passage by early Wednesday. The front is slow to
depart farther away with a wave of low pressure developing along
it and approaching the area mid into late next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The cold front is now entering upstate NY and NW PA early this
evening. An upper level system tracking across Hudson Bay and
into northern Quebec tonight will drag this front through the
region overnight.

Moisture is very limited and just a slight increase in high
clouds is expected and it will remain dry. Winds will gradually
shift from the Southwest to the Northwest overnight. Lows
tonight fall into the 40s and 50s. A MAV/MET/ECS blend was in
good agreement and used.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
High pressure builds back into the region behind the cold
front. Winds will remain from the Northwest and gust into the
upper teens and lower 20s. There is a chance that gusts could be
slightly higher than forecast based on the amount of mixing
that occurs. Conditions remain dry. Winds gradually diminish
overnight, becoming light and variable across the interior.

Max temperatures will climb into the upper 60s and lower 70s on
Friday, with lows Friday night falling into the 40s and 50s. A
MAV/MET/ECS blend was used for the short term temperatures.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Warming trend for the weekend through Monday as the jet stream
remains north of the region with upper level ridging. At this
surface, the dominant feature will be high pressure eventually
moving offshore and the resulting S-SW flow. Mainly clear sky
conditions are expected to continue this weekend.

Clouds increase Monday into Monday night ahead of the next
frontal system. The next chance of rain showers arrives late
Monday night into Tuesday, when a deep upper level trough
approaches from the west.

The trough further deepens Tuesday along the Eastern Seaboard
with increasing meridional flow. This will give plentiful
moisture to a developing frontal system at the surface. The
frontal system will be approaching the region Tuesday into
Tuesday night with the region being in the warm sector to the
east of the low with strengthening southerly flow, thereby
increasing warm air advection. Precipitable water increases to
near 1.5 inches from the moisture advection. This is much above
normal for this time of year. According to OKX sounding climatology,
it would be above the 90th percentile. Some moderate to heavy
rainfall will be possible.

The cold front moves across Wednesday morning, with a
substantial decrease in precipitable water thereafter to less
than 1 inch. The front slows down and is slow to depart away
from the region. The numerical forecast models show weak low
pressure development along it and the low approaching the region
mid into late next week, with rain shower chances continuing.

Temperatures are expected to be well above normal this weekend
through Tuesday with a gradual decline thereafter. Highs this
weekend through Tuesday are forecast to be well into the 70s
with lows trending to be well into the 50s and near 60 for some
locations along the coast and NYC. The highs are forecast to be
more in the 60s for next Wednesday and next Thursday.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
High pressure remains across the mid Atlantic states into
tonight as low pressure tracks through eastern Canada. A weak
cold front, associated with the low, moves across the terminals
late tonight dry. High pressure builds in from the west during
Friday.

Winds SW to SSW around 10 kt with occasional gusts up to 20 kt
diminish early this evening. Winds then veering to the W to
WNW less than 10 kt. Winds will be right around 310 true during
Friday, around 10 kt with frequent gusts up to 20 kt.

     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: Wind may vary from 190 to 220 the next few
hours.

KLGA TAF Comments: Occasional gusts up to 18 kt early this
evening.

KEWR TAF Comments: No unscheduled amendments expected.

KTEB TAF Comments: No unscheduled amendments expected.

KHPN TAF Comments: No unscheduled amendments expected.

KISP TAF Comments: No unscheduled amendments expected.

.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.Friday afternoon-Friday night...VFR. NW winds G15-20KT through
late afternoon.
.Saturday-Monday...VFR.
.Tuesday...MVFR possible in showers.

&&

.MARINE...
Winds east of Fire Island Inlet are beginning to increase this
evening and should reach marginal small craft gusts overnight as
a cold front moves through. These conditions will fall below SCA
levels early Friday morning. Elsewhere, winds and seas will
generally be below small craft advisory levels through Friday
night. There could be some nearshore gusts approaching 25 kt
Friday afternoon on northwest flow.

With high pressure dominating, expecting overall a weak enough
pressure gradient to keep conditions below SCA this weekend
through Monday night on the waters. SCA will be probable for
Tuesday ahead of a cold front as southerly winds strengthen the
southerly fetch. Both wind gusts and seas are forecast to meet
SCA thresholds for the ocean for Tuesday and perhaps all waters
Tuesday night.

&&

.FIRE WEATHER...
A special weather statement has been issued for the entire
region on Friday due to enhanced fire danger. RH values should
decrease to 30 to 35 percent while winds gust 20 to 25 mph,
especially in the late morning and afternoon.

&&

.HYDROLOGY...
No hydrologic problems are expected through Monday night. For
Tuesday through early Wednesday, heavy rain will be possible at
times with potential areas of 1 inch or higher. There is much
uncertainty with exact rainfall amounts. Urban and poor drainage
flooding will be possible.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ350-353.

&&

$$
SYNOPSIS...BC/JM
NEAR TERM...BC/DS
SHORT TERM...BC
LONG TERM...JM
AVIATION...DW
MARINE...BC/JM
FIRE WEATHER...
HYDROLOGY...JM


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