NWS Forecast Discussion - New York City Area

Forecast Discussion for OKX NWS Office
FXUS61 KOKX 250838

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

Low pressure approaches from the south today as passes across
the area tonight. The low moves into New England Thursday. Low
pressure tracks through the area on Friday, followed by a cold
frontal passage over the weekend. High pressure then builds in
for the beginning of next week.


Overall model agreement is noted with regard to main upper level
and sfc features. Weak shortwave approaching from the south
just ahead of northern stream shortwave that tracks across the
Great Lakes region.

Sfc low approaches from the south, moving right up the eastern
seaboard. Gusty easterly winds this morning are anticipated,
then winds should diminish as the low approaches and the
pressure gradient weakens. Rain this morning could be heavy at
times per global models and high resolution simulated
reflectivity, with a focus just east of NYC. In general, QPF
amounts have trended down somewhat, but still expect around an
inch, with a range of 1/2 inch to up to 2 inches in spots. Once
again, cannot rule out some thunder, mainly mid morning into
the afternoon due to weak elevated instability.

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.


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 will develop due to the
recent rain, light winds and minimal T/Td spread.

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

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.


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.


Low pressure approaches from the southwest tonight into
Wednesday, and then moves overhead Wednesday Night.

MVFR conditions continuing to lower to IFR, with moderate to
heavy rain for the morning push. Isolated tstms possible Wed
morning into early afternoon. Potential for LIFR or lower conds
in stratus/fog for evening push.

E winds increase to around 15 kt with gusts to 25 kt for coastal
terminals Wed morning. Winds subside in the early afternoon,
becoming light and variable for evening push.

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: Isolated thunder possible.

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

KLGA TAF Comments: Isolated thunder possible.

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

KEWR TAF Comments: Isolated thunder possible.

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

KTEB TAF Comments: Isolated thunder possible.

KHPN TAF Comments: Isolated thunder possible.

KISP TAF Comments: Isolated thunder possible.

.Wednesday Night...LIFR or lower in stratus/fog possible for
evening push, gradual improvement to VFR late Wed night into
early Thu morning.
.Friday-Saturday...VFR. A chance of showers with areas of MVFR
.Sunday...VFR. W wind 10-15KT, G20-25KT.


Gusty easterly winds in the 20 to 25 kt range this morning will
diminish this afternoon as low pressure approaches from the
south. A few gusts to 30 kt are possible over the ocean waters
this morning.

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.


A widespread 0.50-1.50" of rain is likely today. 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 this morning,
perhaps lingering into late afternoon across SE CT.

No hydrologic impacts are anticipated Fri-Tue.


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


MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ335-
     Small Craft Advisory until 6 PM EDT this evening for ANZ330-
     Small Craft Advisory until 6 PM EDT Thursday for ANZ350-353-



NWS OKX Office Area Forecast Discussion