Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 241036 CCA

Area Forecast Discussion...CORRECTED
National Weather Service New York NY
636 AM EDT Mon Oct 24 2016

Fast moving low pressure and an associated cold front will move
east of the region this morning. High pressure will then gradually
build across from Monday into Wednesday night. A frontal system
will approach from the west on Thursday and move across Thursday
night into early Friday, followed by weak high pressure later
Friday into Saturday. A series of weak frontal systems will then
approach Saturday night into Sunday.


Some minor adjustments were made to temperatures, dewpoints and
POPs for showers. Reduced slight chance of thunderstorms to just
offshore. Rain showers are almost finished as they are very light
on radar and across Southeast Connecticut and Eastern Long Island
and adjacent marine zones.

A fast clipper type low will move across the region early this
morning. High pressure will be slow to build in behind the front.
The center of the high will be moving from South Central Canada
into the Midwest to Western Great Lakes. Meanwhile, a persistent
strong parent low in Quebec will gradually fill in while moving
southeast today.

Rain showers will end early this morning. Expecting some decrease
in clouds with more sun late this morning but clouds will tend to
increase this afternoon. This will be due to diurnal instability
with cyclonic flow aloft allowing for stratocumulus to develop.
With cold air advection expected through the day on a gusty NW
flow, went with cooler guidance of EKD and MAV.


Still enough of a pressure gradient tonight to allow for steady
winds and wind gusts. Rural locations and other locations away
from the coast will have lighter winds and with mostly clear
conditions anticipated, there will be some radiational cooling.
Min temperatures were taken from a blend of MAV/MET guidance which
yields a range from just above freezing to the lower 40s. Rural
locations with the lighter winds and generally across the interior
is where frost can be expected. However, frost coverage is only
expected to be patchy.

For Tuesday, there will be continued cold air advection and
another breezy day with a steep pressure gradient between low
pressure to the northeast of the region and high pressure to the
northwest of the region. Cyclonic flow aloft remains. The airmass
will trend drier with a continued northwest flow. Highs again
were taken from the relatively cooler guidance, MAV, and will be
several degrees cooler than max temperatures of the previous day.


High pressure builds into the region Tuesday night and Wednesday.
Expect a dry, cool period as temperatures Tuesday night fall into
the 30s. Wednesday will be sunny with highs in the middle and
upper 40s.

The high pressure system moves offshore Wednesday night. There
should be enough radiational cooling during the first half of the
night to allow temperatures to fall into the 30s, possibly even some
upper 20s, far north and west of NYC. However, during the second
half of the night, clouds increase as a frontal system approaches
from the west. This could limit how cold temperatures get. There
remains some uncertainty with respect to timing of the
precipitation. Some of the models want to bring the precipitation in
between 09z-12z. If this occurs, temperatures should be cold enough
for some wintry precipitation north and west of NYC. For now, will
carry slight chance/chance pops during the morning, with likely pops
by afternoon. Any wintry precipitation that falls, should quickly
change over to rain after 8am or 9am as temperatures quickly warm.
Most of the precipitation that falls with this system falls Thursday
night.  If the system moves through as quickly as latest guidance
suggest, Friday could be dry throughout, but will continue to keep
chance pops in for eastern Long Island and SE CT.

Forecast certainty diminishes after Friday, with big timing
differences noted with a series of frontal systems moving through.
Have only a broad-brush slight chance PoP from Sat night into
Sunday, and this could change as the more likely time periods for
rain come into focus in later forecast cycles.


High pressure builds in behind a departing cold front.

Mainly VFR, but brief MVFR vsbys/cigs possible in any pre-dawn
showers. Any showers will be brief, not even warranting a tempo

Winds increase this morning and are more likely to prevail north of
310 magnetic for most of the day. Occasional gusts to 30 KT possible
in the city terminals this afternoon.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/

KJFK TAF Comments: Chance winds back towards the west before 11z.
Winds should prevail north of 310 magnetic, but could go south of it
at times from approx 18-21z.

KLGA TAF Comments: Chance winds back towards the west before 11z.
Winds should prevail north of 310 magnetic, but could go south of it
at times from approx 18-21z.

KEWR TAF Comments: Chance winds back towards the west before 11z.
Winds should prevail north of 310 magnetic, but could go south of it
at times from starting at around 15z. Even a chance that it prevails
south of 310 magnetic during this afternoon.

The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: Chance winds back towards the west before 11z.
Occasional gusts 24-29 kt possible this afternoon.

KHPN TAF Comments: Occasional gusts 26-30 kt possible this afternoon.

KISP TAF Comments: Chance winds back towards the west before 11z.
Occasional gusts 26-30 kt possible this afternoon.

.Outlook for 06Z Tuesday through Friday...
.Tonight...VFR with NW winds. Occasional gusts to 20 kt possible.
.Tuesday...VFR. NW winds G25-30 kt, diminishing Tuesday night.
.Wednesday...VFR. NW-NNW G20 kt possible near the coast.
.Thursday...MVFR or lower possible Thursday and Thurs night in rain.
.Friday...Chc MVFR early, otherwise VFR with NW gusts around 25 kt.


SCA in effect on all waters through Tuesday with a steep pressure
gradient remaining between a weakening parent low across Southeast
Canada and strong high pressure building into the Midwest.

SCA conditions continue on the waters Tuesday night but late at
night will be primarily on the ocean and the eastern Sound, and
this could linger possibly into Wed morning. Sub- SCA conditions
are then expected from Wednesday afternoon through much of

SW flow increasing to 15-20 kt Thursday night ahead of a
frontal system should push ocean seas up to 5-6 ft Thu night. Post-
frontal WNW flow could gust up to 25 kt on the ocean on Fri as


Any additional rainfall early this morning will be under a tenth
of an inch.

Thursday and Thursday night, QPF from a passing frontal system is
expected to produce anywhere from 1/2 to 3/4 of an inch of rainfall.
local amounts over an inch are possible. No hydrologic impacts
expected at this time.


MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ330-335-338-


HYDROLOGY...BC/JM is the U.S. government's official web portal to all federal, state and local government web resources and services.