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FXUS61 KOKX 241811
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
211 PM EDT Tue Apr 24 2018

.SYNOPSIS...
Offshore high pressure this afternoon will give way to
low pressure approaching from the south tonight into Wednesday.
The low will move across Wednesday night, then lift to the north
on Thursday. High pressure will briefly build in on Friday, then
give way to another low late Friday into Friday night. A cold
front will move through on Saturday, followed by high pressure
Sunday and Monday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The upper level jet stays north of the region with some upper
level ridging. The surface high will remain offshore and slowly
move farther offshore during today. Clouds will thicken and
lower this afternoon. Still expecting high temps in the lower
60s near the coast and more in the mid to upper 60s away from
the coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Surface low pressure slowly approaches from the Southeast US.
There will be multiple trough approaching from the west in the
upper levels and even some signs of phasing between the northern
and southern branches of the upper jet. Expect most rain tonight
through Wednesday with it tapering off Wednesday night as the
low moves overhead Wednesday night and eventually north of the
region late Wednesday night.

Have delayed onset of rain tonight per latest high-res guidance.
Most of the rain will fall late tonight into Wed morning, with
an AM max coinciding with the approach of the southerly low
level jet. NAM is remarkably farther west with this compared to
the GFS and other models such as the Canadian and ECMWF. Depth
of lift as diagnosed by omega decreases Wednesday afternoon.
Steady rain will become lighter and may have some breaks from
time to time.

Thunderstorm potential will be isolated due to presence of some
low level instability off the Atlantic feed of moisture. Also
related to the Atlantic feed of moisture will be the
precipitable waters, which are forecast to reach 1 to 1.3 inches
Wednesday morning into early Wednesday afternoon. After that,
the precipitable waters decrease, with values closer to 1 inch
through the evening. Further drop of precipitable water to below
half inch by early Thursday.

Ample low level moisture will be present as well Wednesday into
Wednesday evening. The steadier rainfall during the day will be
accompanied by fog but kept coverage patchy. There will be a
period of time Wednesday evening with the center of the low
passing overhead. The less forcing will make for lighter rain
and light winds will keep moisture abundant considering the
earlier rainfall. Expecting areas of fog to develop Wednesday
evening and then become more patchy overnight when winds become
more westerly behind the low.

Used a consensus of raw temperatures for the short term and to
minimize diurnal temperature ranges.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
During the Thursday through Saturday time frame, features to watch
include departing shortwave over the northeast, southern stream
shortwave traversing across the southeast states ahead of vigorous
northern stream shortwave that moves out of the upper midwest toward
the east coast by Saturday.

The southern stream shortwave will lift northeast as the downstream
trough amplifies, with deep SW flow setting up. During the late
Friday time frame, showers ahead of this shortwave and sfc low are
possible, but differences in the models continue, with non GFS
solutions pushing most of the precip just SE of the area. Will
maintain chance Pops with higher probabilities SE zones due to the
uncertainty.

Prior to that, generally dry weather is expected Thursday, Thursday
night and into early Friday. Any lingering rain ends Thursday
morning.

During the Saturday night through Monday timeframe, upper trough
pushes east, and there is the potential for additional showers late
Saturday into Saturday night, although probabilities do not appear
to be high at this time. Greater likelihood would be NW of the area
as trough closes off north of the Great Lakes region.

Upper trough lingers Sunday but gives way to building ridge as sfc
high builds by Monday.

Temperatures remain right around seasonal norms, with Sunday perhaps
a few degrees cooler behind the cold front. Temperatures warm early
next week.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
High pressure off the northeast coast weakens through this
evening as low pressure approaches from the southwest. The
center of the low pressure system moves along the mid Atlantic
coast through Wednesday.

VFR until around 02Z, then ceilings and visibilities lower to
MVFR as light rain develops. Conditions continue to lower to IFR
later tonight, around 06Z. Then IFR conditions continue through
the remainder of the forecast. A period of moderate to heavy
rain is possible, along with embedded thunderstorms, from 10Z to
16Z.

Southerly winds 10-15KT back to the SE then E through this
afternoon. Winds will then remain E to SE. A period of gusty
winds, up to 20 KT, is possible Wednesday morning, mainly along
the coast.


...NY 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: No unscheduled amendments are expected until
early this evening as rain develops.

KLGA TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops.

KEWR TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops.

KTEB TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops.

KHPN TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops.

KISP TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Wednesday...Rain with IFR conditions. Conditions improve
Wednesday night as rain begins to taper off.
.Thursday...VFR.
.Friday-Saturday...VFR. A chance of showers with areas of MVFR
conditions.
.Sunday...VFR. W wind 10-15KT, G20-25KT.

&&

.MARINE...
The weak pressure gradient will keep conditions well below SCA
thresholds today. Tonight, with the continuance of onshore flow,
expecting ocean seas to eventually build to 5-6 ft late. With
the approach of the low level jet, expecting wind gusts of
25-30 kt as the pressure gradient deepens between an approaching
area of low pressure and offshore high. Expecting this to
result in widespread SCA wind gusts for all waters Wednesday
morning and then just remaining on the ocean due to primarily
ocean seas from residual swell for Wednesday afternoon into
Wednesday night. Expecting non-ocean waters to return to mainly
below SCA conditions for Wednesday afternoon into Wednesday
night.

Low pressure passes farther to the north Thursday, with high
pressure briefly building behind through Thursday night. Gusty
westerly winds Thursday, around 20 kt, diminish as the high
builds. However, lingering rough ocean seas persist before
slowly subsiding Friday and Saturday. There is a chance seas
away from the coast linger close to 5 ft through Friday.

A wave of low pressure passes Friday, and a cold front approaches
Saturday. Winds however will remain below 25 kt, sub SCA.

&&

.HYDROLOGY...
A widespread 1.00-1.50" of rain likely tonight into Wednesday,
with the heaviest amounts favored across NYC metro, NE NJ, the
Lower Hudson Valley, and SW CT. Heavy rain will be possible at
times, which could cause minor urban and poor drainage
flooding, especially if the higher end of rainfall ranges are
realized. Expecting the bulk of the rain to fall between 2 AM
and 2 PM Wednesday.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 AM to noon EDT Wednesday for
ANZ330-335-338-340-345.
Small Craft Advisory from 2 AM Wednesday to 6 AM EDT Thursday
for ANZ350-353-355.

&&

$$
SYNOPSIS...Goodman/PW
NEAR TERM...Goodman
SHORT TERM...Goodman
LONG TERM...PW
AVIATION...MET
MARINE...Goodman/JM/PW
HYDROLOGY...Goodman/JM/PW
EQUIPMENT...
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