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fxus61 kokx 201802 
afdokx

Area forecast discussion
National Weather Service New York New York
102 PM EST Wed Nov 20 2019

Synopsis...
deepening low pressure well east of the area today will pass
just east of the Canadian Maritimes tonight into Thursday, while
high pressure builds in from the west. The high moves offshore
Thursday night. A cold front then crosses the area on Friday,
followed briefly by high pressure Saturday. Low pressure may
impact the region Saturday night into Sunday, before high
pressure returns early next week.

&&

Near term /until 6 PM this evening/...
forecast generally on track with only a few adjustments made
with this update. Tweaked the pops based on the band of showers
continuing to rotate across the Rhode Island and Connecticut
border. Generally this precipitation is light but will continue
through much of the afternoon into early evening based on the
latest hi-res models.

Ridging over the mid section of the country and associated
surface high pressure will also build east today. This will
result in a gradually strengthening northerly flow between the
departing low and building high. Gusts to around 20 mph will be
possible by afternoon, strongest along the coast.

There will also be plenty of clouds associated with the upper
trough and wrap around moisture as it passes to the east. Hires
models continue to show weak reflectivity returns developing
across eastern sections of the area this morning into the
afternoon with sprinkles and/or light rain, mainly across
eastern Li and southeast CT. Any rainfall will be light and
likely brief.

Some clearing develops late this afternoon across western
sections of the forecast area.

Daytime highs will be held in check by the cloud cover and
northerly flow with readings not getting out of the 40s. This is
about 5 to 8 degrees below normal.

&&

Short term /6 PM this evening through 6 PM Thursday/...
ridging both aloft and at the surface builds into the area
tonight through Thursday. This will result in clearing skies
and a brisk northerly flow that diminishes late tonight into
Thursday.

Lows tonight will be around 30 well inland, to the lower and
mid 30s along the coast. Highs on Thursday will be in the mid
40s to around 50. These values are a shade below normal.

&&

Long term /Thursday night through Tuesday/...
a fairly progressive flow pattern continues to be shown by the
models for the long term. The main system of concern may occur
Saturday night into Sunday with models and ensembles continuing
to indicate large differences in track which will have
significant implications on low pressure intensity, temperature
profiles, and precipitation amounts.

Before the weekend system, ridging both at the surface and aloft
Thursday night will give way to an amplifying northern stream
shortwave on Friday. A cold front will move across on Friday as the
shortwave swings through New England. The warmest temperatures of
the long term period will occur ahead of the front as readings rise
into the lower and middle 50s inland and upper 50s near the coast.
The overall trend in the models has been for less moisture as the
front moves across and have lowered pops to follow this idea. It is
entirely possible that the front moves across the region dry. A
consensus of the models has the front moving offshore late afternoon
and early evening. Winds will increase Friday night behind the front
with northwest wind gusts 25 to 30 mph.

Progressive ridging moves overhead on Saturday as a split flow
pattern develops across the central states. The southern stream
system of concern is currently located along the southwest coast.
This system will slowly move towards the central states through
Saturday. The northern stream shortwave energy of concern, currently
located over the North Pacific, should near the northern plains on
Saturday. What happens thereafter is likely to be one key piece to
the track and intensity of the low pressure Saturday night into
Sunday. The European model (ecmwf) and GFS differ in where the northern stream energy
moves, with the GFS diving south around the base of the mean upper
trough. The European model (ecmwf) has the energy beginning to interact with the
southern stream wave Sunday morning across the Great Lakes. Both
models have the low pressure of concern tracking over or near the
Long Island coast Saturday night into Sunday despite the differences
in the northern and southern stream interactions, which may lend
some credibility to further north solution. The CMC evolution is
much different with the southern stream system interacting with a
northern stream wave moving across southeast Canada, but the low
pressure is weaker and much more progressive. The spread in the
ensembles is large with several members in the more inland Camp with
several further offshore. While there is some agreement with the
surface pattern on the GFS and ECMWF, run-to-run continuity is low.

Did not make large changes to the previous forecast due to the
aforementioned uncertainties. Saturday will largely be dry with
precipitation chances increasing quickly from south to north
Saturday night. Have increased pops slightly across the southern
half of the area late Saturday night into Sunday morning.

A track closer to the coast like the GFS and European model (ecmwf) indicate would
largely be plain rain across the entire region. A track like the 12z
Tuesday runs of the GFS and ECMWF, which was further off the coast
of Long Island Sunday morning, could introduce some ptype issues
inland, but also concern of how far north the precip reaches.
Temperature profiles are also marginal even with a further offshore
track. The system is progressive which should help to limit the
duration of any impacts with the low.

The system quickly lifts north and east towards the Canadian
Maritimes late Sunday into Sunday night. High pressure returns early
next week. Temperatures should be below normal this weekend and then
approach normal early next week.

&&

Aviation /18z Wednesday through Monday/...
low pressure south of Nova Scotia slowly tracks to the east and
northeast this afternoon and tonight. High pressure slowly
builds in from the west, and will build over the terminals
Thursday.

VFR at the NYC Metro terminals and north and west. Although
brief periods of MVFR will be possible through the afternoon,
then VFR into Thursday. To the east of the NYC Metro terminals,
MVFR with drizzle or light rain, mainly rain at kgon. Brief
periods of VFR are possible, with VFR becoming more likely
early this evening. Timing of the improvement is uncertain, and
forecast confidence is low. Once conditions improve to VFR, VFR
will continue into Thursday.

Winds will remain from the NW, to the right of 310 magnetic,
with more occasional gusts to around 20 kt at the NYC Metro
terminals through this afternoon. Winds northwest to north this evening
into Thursday morning, 10 to 15 kt.



... 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: a chance of MVFR conditions will remain
through this afternoon with ceilings around 2500 ft. Low
confidence with timing of lower conditions. Occasional gusts to
around 22 kt through this afternoon.

Klga taf comments: a chance of MVFR conditions will remain
through this afternoon with ceilings around 2500 ft. Low
confidence with timing of lower conditions.
Occasional gusts to around 22 kt through this afternoon.

Kewr taf comments: occasional gusts to around 20 kt possible
through the afternoon. No unscheduled amendments expected.

Kteb taf comments: occasional gusts to around 20 kt possible
through the afternoon. No unscheduled amendments expected.

Khpn taf comments: MVFR ceiling remain through this afternoon,
although there may be brief periods of VFR. VFR expected after
22z. Low confidence with timing of improving conditions.

Kisp taf comments: MVFR ceiling remain through this afternoon,
although there may be brief periods of VFR. VFR expected after
22z. Low confidence with timing of improving conditions.



Outlook for 18z Thursday through Monday...
Thursday...VFR.
Friday...VFR with a low chance of MVFR in rain showers. Wind SW
around 15 kt, gusts 20-25 kt in the afternoon.
Saturday...VFR, becoming MVFR to IFR in rain at the coastal
terminals, rain and snow north of west of the NYC terminals.
Along the M rain.
Sunday...chance MVFR/IFR in the morning, with conditions
improving during the afternoon. Mainly rain with a chance of
rain and snow north and west of the NYC terminals. Winds northwest
around 15 kt gusting 20 to 25 kt in the afternoon.
Monday...VFR.

&&

Marine...
marginal Small Craft Advisory conditions develop on the ocean waters this
afternoon as northwest winds increase between deepening low
pressure offshore and high pressure building in from the west.
Winds and seas begin to diminish late tonight as high pressure
approaches. Small Craft Advisory seas on the ocean waters could linger into
Thursday morning, especially east of Moriches Inlet.

Winds and seas increase to Small Craft Advisory levels ahead of a cold front on
Friday. The cold front passes east Friday afternoon with Small Craft Advisory
wind gusts on all waters continuing Friday night. There could be
a few gale gusts on the waters east of Moriches Inlet, but this
does not appear to be of long duration. Ocean seas will slowly
subside behind the front.

Conditions will briefly fall below Small Craft Advisory levels on Saturday and
Saturday night. Small Craft Advisory conditions are possible on Sunday as low
pressure may impact the waters. The track of the low will
ultimately determine how high seas build and the intensity and
duration of stronger winds.

&&

Hydrology...
no hydrologic impacts are anticipated through Saturday.

1/2 to 1 1/2 inches of liquid equivalent precip is possible
Saturday night into Sunday with low pressure potentially
impacting the region.

&&

Equipment...
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) is operating
at reduced power until further notice.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until 7 am EST Thursday for anz350-353-
355.

&&

$$
Synopsis...ds/dw
near term...cb/dw
short term...dw

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