Area Forecast Discussion
Issued by NWS Upton, NY

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487
FXUS61 KOKX 251534
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1134 AM EDT Wed Apr 25 2018

.SYNOPSIS...
Low pressure will approach from the south today, and then pass
across the area tonight along with a trailing cold front. The
low will move into New England on Thursday. Another low will
move through on Friday, followed by a cold frontal passage over
the weekend. High pressure will then build in early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Made some changes based on latest radar and hi-res model trends.
SE H9 LLJ of 50 kt transporting moisture up into the area and
providing low level convergence/lift to produce light rain over
most of the area attm. Hi-res models are way overdoing
convective rainfall potential, and now think most of the rain
into this afternoon as the LLJ lifts up across the area should
be light to moderate, with maybe still a rumble of thunder
possible this afternoon across eastern Long Island and SE CT.

Satellite imagery also shows dry slot riding up from the south,.
so expect rain to come to an end in most places late this
afternoon, and would not rule out some peeks of sun late in NYC
metro before sunset given partial clearing that is taking place
in southern DE and off the southern NJ coast.

Gusty E-SE winds this morning should diminish this afternoon as
the low approaches and the pressure gradient weakens.

Temps will struggle to rise much, with late day highs expected
once the steadier rain begins to taper somewhat. Blended MET,
MAV and ECS data.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Sfc low moves in the general area of NYC tonight as northern
stream possibly phases with weakening shortwave, although
degree of phasing remains in question.

Regardless, winds lighten, and fog may develop due to the recent
rain, light winds and minimal T/Td spread.

A few showers are possible as the low and sfc trough pass.

Any fog lifts late tonight as westerly wind flow behind
departing low to the north stirs up the boundary layer, and
drier air moves in. Lows range from the upper 40s to lower 50s
per MOS blend.

On Thursday, sunshine returns, mixed with a few clouds and any
rain showers remain to the north, closer to upper shortwave, sfc
low. Westerly flow will allow for deeper mixing, and temps
rising well into the 60s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The ECMWF and GFS are in very good agreement with low pres tracking
thru the area Fri. The sys is the remnants of the upr low currently
over Neb. The modeling indicates a weak sys as the low runs out
ahead of an approaching upr trof. The thermals indicate all rain.
The timing is late Fri and Fri ngt attm, although some timing changes
cannot be ruled out. A more intense low would be possible if the upr
trof arrives quicker, or if the remnant low slows. A cold front then
brings a chc for some more shwrs on Sat. Everything is progged to
clear out on Sun with some fair wx clouds likely as the cold pool
aloft passes thru. The post frontal high reaches PA Sun ngt. This
should be close enough to allow for the winds to decouple and
produce prime radiational cooling cond. As a result, the colder MEX
was used for temps Sun ngt as opposed to the warmer model blends.
Frost/freeze issues are possible if this unfolds as currently
expected. Fair wx with a warming trend for the beginning of next
week with an upr ridge building into the region.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Low pressure approaches from the southwest tonight into
Wednesday, and then moves overhead Wednesday Night.

IFR or less through midnight. Light to moderate rain will
continue today. Some pockets of heavy rain will be possible
during the mid to late morning hours. Can not rule out an
isolated tstms east of NYC into early afternoon. Potential for
LIFR or lower conds in stratus/fog for evening push. LIFR
stratus and fog expected through the overnight.

Conditions improve late tonight/early Thursday back to VFR.

E winds are increasing with to gusts to 25kt for coastal
terminals Wed morning. Winds subside in the early afternoon,
becoming light and variable for evening push. Winds become
westerly late late tonight/early Thursday morning.

LLWS possible with SE winds at 40-45 kt at 2 kft.

     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: Occasional wind gusts may be higher than
forecast.

The afternoon KJFK haze potential forecast is YELLOW...which implies
slant range visibility 4-6SM outside of cloud.

KLGA TAF Comments: Occasional wind gusts may be higher than
forecast.

The afternoon KLGA haze potential forecast is YELLOW...which
implies slant range visibility 4-6SM outside of cloud.

KEWR TAF Comments: Occasional wind gusts may be higher than
forecast.

The afternoon KEWR haze potential forecast is YELLOW...which
implies slant range visibility 4-6SM outside of cloud.

KTEB TAF Comments: Occasional wind gusts may be higher than
forecast.

KHPN TAF Comments: High confidence of IFR or less today.

KISP TAF Comments: High confidence of IFR or less today.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.Thursday...VFR.
.Friday-Saturday...VFR. A chance of showers with areas of MVFR
conditions.
.Sunday...VFR. W wind 10-15KT, G20-25KT.

&&

.MARINE...
Gusty E-SE winds 20-25 kt this morning will diminish this
afternoon as low pressure approaches from the south. A few gusts
closer to to 30 kt are possible over the eastern ocean waters.

Seas build in response to the increasing east winds. As the low
moves nearby, then to the north tonight, light winds will shift
to the west and pick up in speed once again. Westerly winds are
forecast Thursday as the low passes further to the north.

SCA conditions are expected through Thursday, mainly for
elevated ocean seas, but winds should gust as well.

For non ocean waters, SCA remains up for this morning, but will
extend eastern LI Sound and Peconic/Gardiners Bays through 6 pm
as winds may linger across these locations a bit longer.

Low pres passing thru the region on Fri followed by a cold frontal
passage on Sat will keep seas at sca lvls on the ocean. Elsewhere,
winds and waves look to remain blw criteria. Winds and seas blw sca
lvls all waters Sun-Tue with high pres building in from the w.

&&

.HYDROLOGY...
An additional 1/4 to 1/2 inch of rain expected through tonight.
Locally higher amounts of 1/2 to 3/4 inch are possible across
parts of Long Island and southern CT. Only localized nuisance
impacts expected.

&&

.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 until 2 PM EDT this afternoon for ANZ335-
     338-345.
     Small Craft Advisory until 6 PM EDT this evening for ANZ330-
     340.
     Small Craft Advisory until 6 PM EDT Thursday for ANZ350-353-
     355.

&&

$$
SYNOPSIS...JMC/Goodman/PW
NEAR TERM...JMC/Goodman/PW
SHORT TERM...PW
LONG TERM...JMC
AVIATION...CB/BC
MARINE...JMC/PW
HYDROLOGY...JMC/Goodman/PW
EQUIPMENT...



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