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000
FXUS61 KOKX 242011
AFDOKX

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

.SYNOPSIS...
Low pressure over the Southeast states will move northeast
toward the area tonight into Wednesday, then pass over the area
Wednesday night, with a trailing cold front also passing
through.

Weak high pressure will briefly build in on Thursday, then give
way to another low late Friday into Friday night. A cold front
will move through on Saturday, followed by high pressure Sunday
through Tuesday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Ridge axis aloft is passing east, with clouds lowering and
thickening from NYC metro south/west. Steady rains are still
well to the southwest over central/eastern Maryland, and are not
likely to arrive in the NYC metro area until about 11 PM,
though a few spits of light rain are possible here and there
beforehand this evening in the onshore flow between the
approaching low and departing offshore high pressure.

Low temps are a blend of GFS/NAM MOS and 2m raw temps, with
lower 50s in NYC metro and western Long Island, and mid/upper
40s elsewhere.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Combo of a decent shot of Atlantic inflow and elevated
instability ahead of the approaching surface low will lead to
rain, heavy at times, along with chance of thunder as TT
increases to near 50 and Showalter indices decrease to near of
below 0C. This area should lift NE and off the eastern New
England Coast Wed night, leaving the area in a col for most of
the night with light rain and patchy fog developing. NWP
guidance shows some phasing of northern/southern branches of the
jet stream late Wed night, and as this takes place the southern
stream low and mid level shortwave trough should pass through
late Wed night, along with a cold frontal passage associated with
the northern branch of the jet stream and a surface low well to
our north. Elevated convection could be reinvigorated by this
cold front, and so have kept slight chance mention of thunder in
the forecast for Wed night.

Temps will be below seasonal norms but certainly not unusual for
a springtime rain event, with not much diurnal changes. Highs
Wed will be in the 50s, and lows Wed night in the upper 40s and
lower 50s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
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.

Any lingering rain should end early Thu morning with weak
ridging and dry weather returning through Thu night. Meanwhile,
the aforementioned southern stream shortwave will lift
northeast as the downstream trough amplifies, with deep SW flow
setting up. There are some differences aloft, the American
models track the shortwave further west than the EC/CMC/UKMET,
leading to higher rain amounts on Fri. Will need to fine tune
this in the coming days, but for now have increased CHC PoPs a
bit.

During the Saturday night through Monday timeframe, upper
trough pushes east, and there is the potential for additional
showers associated with a weak cold front 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 /20Z 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, with gusts to around 20 KT, 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. Occasional gusts may
continue a couple hours passed 22Z.

KLGA TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops. Occasional gusts may
continue a couple hours passed 22Z.

KEWR TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops. Occasional gusts may
continue a couple hours passed 22Z.

KTEB TAF Comments: No unscheduled amendments are expected until
early this evening as rain develops. Occasional gusts to around
20 KT possible through 23Z.

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. Then as
the pressure gradient tightens ahead of the approaching sfc low,
expect wind gusts gusts of 25-30 kt mainly during the first half
of Wed. Seas on the ocean waters should remain AOA 5 ft into
Sat before subsiding from W to E as the pressure gradient
weakens.

&&

.HYDROLOGY...
A widespread 1.00-1.50" of rain likely late tonight into
Wednesday. Heavy rain at times could cause minor urban and poor
drainage flooding, especially if the higher end of the expected
rainfall range is realized. Expecting the bulk of the rain to
fall between 2 AM and 2 PM Wednesday, perhaps lingering into
late afternoon across SE CT.

&&

.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/24
NEAR TERM...Goodman
SHORT TERM...Goodman
LONG TERM...24
AVIATION...MET
MARINE...Goodman/24
HYDROLOGY...Goodman/24
EQUIPMENT...