859
FXUS61 KOKX 160257
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
957 PM EST Sun Dec 15 2024
.SYNOPSIS...
A weakening disturbance moves across the area tonight through Monday
followed by a quick moving frontal system Monday night into Tuesday
morning. Weak high pressure moves in briefly Tuesday night into early
Wednesday. Next frontal system moves in Wednesday afternoon into
Wednesday night. Its associated cold front moves east of the region
Thursday. High pressure returns Thursday night through Friday but
its center stays north of the region. Low pressure areas approach
from the Great Lakes and offshore in the Atlantic for next
weekend.
&&
.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
Light snow beginning to develop across parts of Orange County as
of 2Z, and will expand east over the next several hours.
Temperatures near or just above freezing across the interior
should drop a couple of degrees as the precip moves in with dew
pts in the 20s. Rain still expected for coastal locales. Forecast
remains on track.
Echoes of radar reflectivity on radar traversing parts of the
region are encountering drier air with some places getting
either very light precipitation or no precipitation at the
surface initially. Atmospheric column becomes more moist by mid
to late evening, when POPs more rapidly increase and chances
grow for precipitation within the region.
Mid level shortwave with weak surface reflection approaches from the
west tonight and passes through on Monday. Associated precip becomes
likely towards midnight with the best overall chances overnight into
the first half of Monday morning. There will still be a good chance
of precip however during the afternoon in some areas - particularly
near the coast where low level warm advection will be greater.
A brief window of wet-bulbing due to erosion of lingering dry air
supports an onset of light snow across the interior of the Lower
Hudson Valley, interior NE NJ, and into interior CT. An elevated
warm nose will be pushing through at the same time with above-
freezing temps in this layer reaching the entire forecast area by
the end of the night. Since this warm layer is at a low altitude,
there will be very little time for anything falling to refreeze into
sleet. So while can`t rule out a little sleet, thinking is that the
precip types for this event will be rain, freezing rain and snow.
For the interior areas, after thermal profiles no longer support
snow or when mid levels dry out and preclude snow as a potential
precip type, 2-meter temperatures will be slowly rising, however
ground temps may take some time to respond given the recent stretch
of cold weather. This will extend the threat of freezing rain well
into Monday morning. Further south towards the NYC metro, Long
Island, and coastal CT, plain rain is expected.
No changes to the Winter Weather Advisory, but while precip may be
lighter farther east within the advisory area, it only takes trace
amounts of freezing rain to cause hazardous travel. Still not enough
confidence to extend the advisory farther east into Northern New
London as precip probably holds off till daybreak and looks to be
more spotty in nature. Will continue to mention the ice potential
here in the HWO specifically during the morning commute.
Snowfall amounts are light - under 3 inches, and ice accumulations
anywhere from a light glaze to several hundredths of an inch.-- End Changed Discussion --
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
The next system will be quick to follow the departing shortwave. A
cold front associated low pressure tracking east through Canada
approaches Monday night and passes through during Tuesday morning.
Thermal profiles will be warm enough everywhere for rain. The rain
associated with the front will overspread the area Monday night and
quickly sweep off to the east Tuesday morning. Rainfall amounts are
around one quarter inch since the system is progressive and the
majority of the more organized forcing passes to the NW. Becoming
mostly sunny Tuesday afternoon. With west winds and 900mb temps
progged at 4-5C in the afternoon, went a couple degrees above NBM
for high temperatures. Highs around 60 for NE NJ, NYC and much of
LI, and upper 50s for most other areas.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
An active pattern in place towards mid and through late week. Taking
a look at 250mb, strong upper jet streak north of the region Tuesday
night into Wednesday. This moves across the local area Wednesday
night into Thursday. Then, jet streak dives farther south Friday
into next weekend, setting up south of the region.
At 500mb, the upper pattern transitions from zonal Tuesday night to
a trough Wednesday night into Thursday. Then, briefly quasi-zonal
Thursday night before a longer wavelength trough sets up in the
region Friday into next weekend.
Surface pressure gradient not that tight Tuesday night through
Friday night. The pressure gradient tightens next weekend with
offshore developing low pressure and strengthening high pressure
moving in from the west. There is possibility for low and high
pressure to strengthen more than forecast for next weekend.
Regarding temperatures, overall decreasing trend. Starting out above
normal with temperatures towards midweek, then closer to normal
Thursday and Thursday night, and then getting more below normal
thereafter. The coldest airmass of the entire forecast period going
out through the next week is forecast for next weekend when forecast
highs once again will stay in the 30s.
Regarding precipitation, mainly a rain event for Wednesday into
early Thursday. Generally around 0.5 to 0.75 inch of rain is
forecast. Only wintry precipitation potential with this system is on
the backside with cold air advection late Wednesday night into early
Thursday morning for portions of the interior. However, drier air
advecting in will really limit the precipitation chances overall.
Potential for more snow Friday into the weekend. One low is
approaching from the Great Lakes and one low is far offshore.
Lows are not too strong. Chances for precipitation mainly in the
form of snow are forecast, but stays mostly under 50 percent. The
models are not really showing any significant phasing or strength
of low pressure. Might be more occasional snow shower activity
for Friday into next weekend.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
High pressure remains off the New England coast tonight as a
disturbance approaches. A warm front slowly approaches from the
south Monday.
Ceilings continue to lower near 3 kft this evening, and MVFR
ceilings develop by 6Z at most terminals, then continuing to
lower through the night with IFR likely by 12Z Monday. Brief
periods of LIFR are possible from early to mid Monday morning.
Visibilities during the time frame will generally be MVFR for
the city terminals, with brief periods of 2SM or lower at times.
Outlying terminals will see IFR vsbys, with brief periods of
LIFR possible.
Light snow beginning to break out at KSWF as of 3Z, expanding
eastward as light rain into city terminals by 6Z. The light snow
at KSWF changes to light freezing rain after 9Z before becoming
plain rain into late morning. Light rain or showers persist
through much of the day across the region, becoming intermittent
in the afternoon, then redeveloping everywhere Monday evening.
Several hundredths of an inch of ice along with snow under 1 inch
expected at KSWF.
NE to SE flow is expected through the TAF period. Speeds will
remain near or under 10 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Timing of category changes and rain may be off by a few hours.
Brief LIFR cigs cannot be ruled out Monday.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday Afternoon: MVFR or IFR with rain likely.
Monday Night-Tuesday: IFR and rain. The rain ends in the morning
afternoon with conditions returning to VFR by afternoon. S-SW
flow late Monday night into Tuesday morning, becoming W Tues
afternoon.
Wednesday-Wednesday night: VFR early becoming MVFR-IFR with rain by
evening into the night. NW gusts 15-20 kt possible late Wednesday
night.
Thursday: Return to VFR in morning. NW gusts 15-25kt.
Friday: VFR. E/SE gusts up 15-20 kt possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Conditions will remain below SCA levels on the waters through
Monday. Advisory level winds and seas look likely on the ocean as
early as late in the day Monday, and lasting through Tuesday as the
next frontal system moves across the waters. As for the other
waters, gusts of around 25kt gusts anticipated late Monday night
into Tuesday morning. SCAs have been issued accordingly.
Outside of the ocean, below SCA conditions are forecast Tuesday
night through Friday night. Wind gusts forecast stay below SCA
levels for the same time period. However, there will be chances for
SCA level wind gusts for all waters Thursday into Thursday
evening behind a cold front, with cold air advection.
The ocean is forecast to have lingering SCA level seas Tuesday night
as well as Wednesday night through Thursday. In addition, some
eastern portions of the ocean could have SCA seas Thursday night.
Sub-SCA forecast for ocean on Friday. Some eastern portions of the
ocean could again have SCA seas Friday night.
&&
.HYDROLOGY...
There are no hydrologic concerns through next weekend.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Winter Weather Advisory from 1 AM to 11 AM EST Monday for
CTZ005>007.
NY...Winter Weather Advisory until 11 AM EST Monday for NYZ067>070.
NJ...Winter Weather Advisory until 11 AM EST Monday for NJZ002.
MARINE...Small Craft Advisory from midnight Monday night to noon EST
Tuesday for ANZ331-332-335-340-345.
Small Craft Advisory from midnight Monday night to 6 AM EST
Tuesday for ANZ338.
Small Craft Advisory from 4 PM Monday to 6 PM EST Tuesday for
ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/JM
NEAR TERM...JC/JM/DR
SHORT TERM...JC
LONG TERM...JM
AVIATION...DR
MARINE...JC/JM
HYDROLOGY...JC/JM