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fxus61 kokx 231148 
afdokx

Area forecast discussion
National Weather Service New York New York
648 am EST Thu Nov 23 2017

Synopsis...
high pressure builds to the south through Friday, then pushes
well of the Atlantic coast into Saturday. A cold front
approaches from the west Saturday, then crosses the area
Saturday night. High pressure then builds in from the southwest
through Monday night, then slides off the mid-Atlantic coast
Tuesday. A cold front approaches from the west Tuesday night,
then crosses the area on Wednesday.

&&

Near term /until 6 PM this evening/...
made minor changes this update to reflect the latest trends in
observations and guidance. The forecast appears on track.

A 700-500 hpa trough approaches today, but with dry low-mid
levels it should be dry, with just some patchy high clouds out
ahead of it, mainly in the afternoon.

Highs today should be 5-10 degrees below normal, mainly from
around 40 to the lower 40s.

&&

Short term /6 PM this evening through 6 PM Friday/...
the trough crosses the region in pieces, with the northern
stream portion crossing the area this evening, and the southern
stream portion overnight. Given the unphased nature of the
trough and relatively dry mid-upper levels, have continued with
a dry forecast for tonight. Lows tonight should be around 5
degrees below normal, mainly from the mid 20s to around 30,
except low-mid 30s in the NYC Metro.

Southwest flow sets up aloft on Friday, with no notable
shortwave progged to pass over the area in this flow, it should
be dry, with minimal, if any cloud cover. Highs should be near
normal.

&&

Long term /Friday night through Wednesday/...
SW flow aloft continues Friday night, and absent any shortwaves
in the flow, it should continue to be dry, with minimal cloud
cover. Lows Friday night should be near to slightly above
normal.

A deep layered trough approaches on Saturday, models do differ
on how well phased it is. The GFS is the most coherent between
the northern and southern streams, while the European model (ecmwf)/CMC/NAM have
the northern stream trough progressing quicker than the
southern stream trough, and shearing out as it lifts NE. The
sref has similar coherence to the GFS, but is slower with the
overall system.

Noting that the northern stream currently is more progressive
than the southern stream, have leaned more towards the
European model (ecmwf)/CMC/NAM Saturday/Saturday night. However, do have slight
chance pops mainly Saturday afternoon (and into the evening far
east zones) with the addition of lift just ahead of the surface
cold front.

The region remains at the base of a northern stream trough
Sunday-Sunday night. However, given dry low levels, have
continued with a dry forecast.

Deep layered ridging builds from Monday into Tuesday, then
slides off shore through Tuesday night. Subsidence associated
with the ridge should keep things dry, with minimal cloud cover.

Models then differ on Wednesday. The CMC has a closed low north of
the Great Lakes with and associated full latitude trough
building into the deep south. The European model (ecmwf) has a shearing out
northern stream shortwave race by to the north. The GFS is
fairly similar to the ECMWF, however, not quite as flat with the
shortwave/overall pattern over the eastern U.S. Since the CMC
appears to be a clear outlier, went with a GFS/European model (ecmwf) blend. With
expectation of relatively dry-low to mid levels and limited
dynamics to work with, limited pops on Wednesday to slight
chance, as some isolated showers cannot be ruled out.

Temperatures Saturday-Wednesday, start out above normal on
Saturday, should be below normal Sunday-Monday, then above
normal Tuesday and Wednesday.

&&

Aviation /12z Thursday through Monday/...
high pressure builds in from the west today into tonight.

VFR. Northwest winds around 10 kt (right of 310 magnetic) for the
morning push, likely backing to the west (left of 310 magnetic)
in the afternoon. Winds subsiding to less than 5 kt this
evening.

New York 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: timing of winds backing from right of 310
magnetic to left of 310 magnetic could be off by 1 to 2 hours.

The afternoon kjfk haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Klga taf comments: timing of winds backing from right of 310
magnetic to left of 310 magnetic could be off by 1 to 2 hours.

The afternoon klga haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kewr taf comments: timing of winds backing from right of 310
magnetic to left of 310 magnetic could be off by 1 to 2 hours.

The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kteb taf comments: timing of winds backing from right of 310
magnetic to left of 310 magnetic could be off by 1 to 2 hours.

Khpn taf comments: no unscheduled amendments expected.

Kisp taf comments: no unscheduled amendments expected.

Outlook for 12z Friday through Monday...
Friday-Friday night...VFR. Light west winds for the morning push,
backing to the SW by late Friday morning/early afternoon.
Saturday-Saturday night...low prob of -shra and MVFR with
frontal passage. Windshift from SW to northwest late Sat/Sat eve.
Sunday...becoming VFR. Northwest winds g20-30kt forecast.
Monday...VFR. Winds back to more westerly and decrease. Gusts
15-20kt possible.

&&

Marine...
made minor changes this update to reflect the latest trends in
observations and guidance. The forecast appears on track.

Wind gusts are expected to fall below Small Craft Advisory (sca)
levels early this morning, but seas remain at 4 to 6 ft.
Although winds waves will begin to decrease, wna/nwps guidance
indicating a 5ft@10 sec period swell beginning to work into the
waters this morning and being slow to subside through Friday.
Hints of this swell just beginning to show up at 44066 and 44008
this morning.



So 5 ft seas are likely today on the ocean. With a slight
strengthening of pressure gradient and caa tonight, the marginal Small Craft Advisory
seas may linger through tonight into Friday, particularly for
eastern ocean waters.

SW gradient picks up late Friday into Friday night, which would
signal likelihood for Small Craft Advisory ocean seas remaining/developing late
Friday into Friday night and continuing into Saturday, particularly
east.

Sub Small Craft Advisory conditions are expected on all non-ocean zones through
Saturday.

Small Craft Advisory conds likely all waters late Saturday night through Sunday
behind a cold front, with improvement on Monday as high pressure
builds to the south.

Ocean seas may builds towards Small Craft Advisory once again Tuesday into Tuesday
night ahead of next frontal system.

&&

Hydrology...
with the potential for most, if not all areas to be dry through
next Wednesday, no significant hydrologic impacts are expected
through then.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until 7 PM EST this evening for anz355.
Small Craft Advisory until 7 am EST Friday for anz350-353.

&&

$$
Synopsis...maloit
near term...maloit

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