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fxus61 kokx 270923 
afdokx

Area forecast discussion
National Weather Service New York New York
523 am EDT Mon Mar 27 2017

Synopsis...
a warm front will slowly lift through the tri-state region
today. A cold front with a wave of low pressure passes through
the region Tuesday night. High pressure builds in for
Wednesday and Thursday, and shifts offshore Thursday night. A
low pressure system approaches from the central United States
Thursday night and impacts the region Friday and Saturday. High
pressure returns for Sunday.

&&

Near term /until 6 PM this evening/...
drizzle will continue this morning, with increasing lift
allowing for areas of steady rain to develop. Radar returns are
already showing this rain west of the Hudson River. It will be
difficult to clear out this afternoon behind the front, with
significant moisture at or below 4000 ft depicted by the models.
This will keep the area from warming up to Max potential, and
therefore limiting instability. Regardless, there could be
enough support from the upper jet to produce some showers this
afternoon into the early evening after the frontal passage. A
broad model consensus was used for temperatures today, with an
emphasis given to the raw model output.

&&

Short term /6 PM this evening through 6 PM Tuesday/...
convergence aloft in the dry layer does not seem conducive to
much rainfall tonight. As a result, only low chances for rain
were included in the forecast. If rain does develop, it may turn
out to be mainly sprinkles or light drizzle. Surprisingly big
differences exist between the NAM and GFS for Tuesday. The NAM
holds off on the deep lift, and therefore the bulk of the rain,
for the entire day. The GFS brings in rain by morning. The European model (ecmwf)
supports the NAM, by keeping the bulk of the rain with the main
shortwave. The GFS appears to be kicking off convection over
Pennsylvania that brings residual energy in. The forecast sides
with the drier solutions, although there may be some showers or
pockets of light rain with weak vorticity advection and a moist
airmass. A blend of the models was used for temperatures.

&&

Long term /Tuesday night through Sunday/...
a southern stream shortwave over the Oklahoma and Kansas area
this Monday morning will weaken and track to the mid Atlantic
coast Tuesday and offshore Tuesday night. Meanwhile, a northern
stream longwave trough moving through south central Canada moves
east and passes into northern New England Tuesday night. There
is still some differences in whether or not the two systems will
phase, with consensus for the south stream to be more
progressive and remain separate, and farther south than other
models, while dampening and exiting the mid Atlantic. The
southern movement will keep an associated warm front to the
south. This southern and separate solution has been the trend
the last several runs. With higher confidence in precipitation
affecting the area, mainly the southern half of the cwa, will
have likely probabilities Tuesday night.

A northwest flow will persist across the region as surface
high pressure builds to the north and the upper northern stream
trough moves slowly off the northeast coast through Thursday
night. The surface high weakens Thursday night as another
southern stream shortwave approaches, however the upper ridge is
holding with the axis shifting east of the area Friday. The
southern stream system will also be weakening as the wave tracks
east. Have brought in chances late Thursday night into Friday
and this may be too quick if the ridge holds. The weakening low
will re develop off the mid Atlantic coast Saturday with chances
of precipitation remaining into Saturday night. Cold air will
be in place across the northern tier and some of the
precipitation may fall as snow or a rain snow mix.

Weak high pressure returns for Sunday into Monday.

&&

Aviation /09z Monday through Friday/...
low-level ridge continues to weaken and gives way to an
approaching warm front to the south for late this morning. This
front will lift slowly through during the late morning/early
afternoon hours, possibly washing out across or just north of
the area.

Lower ceilings, drizzle, and fog continue to work in from the
SW. Conditions have generally lowered through the overnight
with widespread LIFR at most terminals leading up to the morning
push.

IFR conditions could last through much of the period, especially
to the north and east of the NYC terminals due to the
uncertainty with the timing and final placement of the warm
front. Tafs have been updated to Show Low level wind shear for most terminals
for the mid to late morning. Moderate confidence in improving
visibilities and ceilings from 18z to 22z across most terminals,
before lowering ceilings and visibilities again for Monday
night into Tuesday morning.



..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: winds generally under 10kt but with low confidence
in timing of wind direction change for the early afternoon.

Klga taf comments: winds generally under 10kt but with low confidence
in timing of wind direction change for the early afternoon.

Kewr taf comments: winds generally under 10kt but with low confidence
in timing of wind direction change for the early afternoon.



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



Kteb taf comments: winds generally under 10kt but with low confidence
in timing of wind direction change for the early afternoon.

Khpn taf comments: winds generally under 10kt but with low
confidence in timing of wind direction change for the early
afternoon.

Kisp taf comments: winds generally under 10kt but with low
confidence in timing of wind direction change for the early
afternoon.



Outlook for 09z Tuesday through Friday...
Monday night-Tue night...IFR likely, LIFR possible with rain/low
clouds/fog.
Wednesday...VFR. Northwest winds g15-20kt.
Thursday...VFR.
Friday...chance of rain with MVFR or lower conditions,
especially late in the day and at night. East winds g20kt along
the coast.

&&

Marine...
waves were running about 1-2 feet above wavewatch this morning.
With winds below 25 kt, the Small Craft Advisory has been
converted to one for hazardous seas into tonight. Winds and seas
will be below Small Craft Advisory levels on Tuesday.

A wave of low pressure passes to the south of the forecast
waters Tuesday night along with a cold front. Winds and seas are
expected to be below small craft levels across the forecast
waters. Northwesterly winds will develop behind the cold front
and then increase into Wednesday and Wednesday night as high
pressure builds to the north. Minimal small craft conditions
will be possible across the ocean waters Wednesday night into
Thursday in the northwest flow.

Then as high pressure builds over the waters Thursday winds and
seas will fall below advisory levels.

A southeasterly flow develops Friday and increases as low
pressure approaches the mid Atlantic region. Marginal Small
Craft Advisory wind gusts will be possible Friday night into
Sunday, mainly across the ocean waters. In additions ocean seas
will build to small craft levels late Friday and remain into
Sunday.

&&

Hydrology...
around a half inch of rain is possible today. Additional rain of
a quarter inch or less is forecast for Tuesday. One to two
tenths of an inch of rainfall is likely Tuesday night. Then dry
conditions expected Wednesday and Thursday.

No hydrologic concerns are anticipated.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory for hazardous seas until 2 am EDT Tuesday
for anz350-353-355.

&&

$$
Synopsis...12/met
near term...12
short term...12

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