693
FXUS61 KOKX 061147
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
647 AM EST Thu Feb 6 2025
.SYNOPSIS...
Low pressure impacts the area today before moving to the northeast
tonight. High pressure builds back into the area for Friday and into
the first half of the weekend. Another area of low pressure
impacts the area Saturday night into Sunday. High pressure
returns Sunday into Monday night. A series of low pressures may
pass south of Long Island Tuesday and Wednesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Low pressure will impact the area today with a variety of
precipitation types expected across the CWA throughout the day.
Waves of moisture and precipitation are moving through the CWA.
Precipitation type seems to be driven primarily on intensity.
Higher intensity precipitation is allowing for some low level
dynamic cooling and eroding of the low-level warm layer
resulting in a primarily snow or snow/sleet mix. As the
intensity lightens, a freezing rain/freezing drizzle and light
sleet has been observed. Over the next several hours, warm air
aloft should win out, eventually causing all precipitation to
transition to a plain rain, first at the coast, then more
inland by mid to late morning.
Precipitation is expected to come to an end this afternoon.
Some patchy fog development is also possible late this afternoon
and into this evening as a moist surface and generally light
winds will support fog development.
Total snow accumulations of generally around an inch for Long
Island and 1-2 inches for the rest of the CWA possible. A glaze
of ice is possible along the coast as well with up to a tenth
of ice possible for northern areas. As such, Winter Weather
Advisories are in effect for this icing potential to impact the
morning commute.
Winds will increase from the W and NW tonight, allowing for any
fog to mix out as drier air moves in. Lows tonight will be in
the low to middle 30s.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
High pressure builds in behind the departing low on Friday. This
will bring in a drier airmass, though a tightening pressure
gradient will allow for windy conditions on Friday with gusts
upwards of 30-35 mph, locally to 40 mph possible. High
temperatures on Friday will be in the middle to upper 30s.
High pressure continues to build into the area with dry
conditions and diminishing winds Friday night. Low temperatures
will be in the teens for the inland areas with the low to middle
20s expected for the coast. The cold airmass remains in place on
Saturday as high pressure begins to slide overhead. Highs will
be in the low to middle 30s for much of the area on Saturday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Confidence is increasing in active period with several chances for
wintry weather.
*Key Points*
*Recent model trends indicate increasing probabilities for an
accumulating/advisory level snowfall and low potential for warning
level snowfall across the interior Saturday night.
*The accumulating snow may transition to a wintry mix late Saturday
night, especially closer to the coast.
*A series of low pressures may pass off the Middle Atlantic Tuesday
into Wednesday with another chance for snow.
Fast, zonal flow aloft will continue into early next week. The
modeling has been in excellent agreement with a fast moving middle
level shortwave and strong upper jet moving towards the region
Saturday night. The differences in the guidance continue be with the
exact track of the parent low and its transfer to the coast by early
Sunday morning. The system is fast moving and will pull away from
the area Sunday morning and early Sunday afternoon.
There have a been a few notable dprog/dt trends over the last
several cycles of the models that may be beginning to shed a little
clearer picture of the evolution of the event. The parent low will
likely be moving across the Ohio Valley in the evening with its
associated warm front approaching from the southwest. The trend has
been for the parent low to track into western PA rather than up into
western NY. The low then transfers to a secondary low along and just
off the Middle Atlantic coast. As a result, the model consensus is
starting to lean towards a colder solution especially at the
beginning of the event as departing high pressure leaves behind a
cold and dry air mass Saturday evening. There may still be some
mixing/ptype changes closer to the coast as warmer air aloft tries
to get into the area late at night. Some warmer surface air may also
try to edge north across portions of the NYC metro and Long Island,
but the magnitude of this is a bit uncertain. If the secondary low
develops quicker, it may help keep the flow more N or NE and hold
back some of the warmer air. These are some of the mesoscale details
that still need to be worked out in the next 24 to 48 hours.
The current anticipated evolution will be a period of accumulating
snow beginning Saturday night 7pm to 10pm, from west to east. The
system will likely have more moisture and more organized dynamics to
work with compared to the event today (early Thursday morning).
Model soundings indicate strong lift in the Dendritic growth zone
along with thermal profiles favorable for all snow area wide the
first half of the night. Moderate snow is possible and there could
be some bands of heavier snow with some of the modeled 850-700mb
frontogenesis. Sometime around or just after midnight some warmer
air aloft may try to bring a mix of of snow and sleet along the
coast and potentially into the NYC metro. Most of the global models
show this, but the timing and magnitude differ. However, given how
quickly the modeled QPF increases before the potential transition,
advisory level snowfall is possible even down to the coast.
Locations further inland should stay snow well into the early
morning hours with any mixing potentially coming from the loss of
snow growth and weaker lift. Some colder air could wrap back into
the system as the storm pulls away early Sunday morning, but lift is
not as impressive. Any lingering precip should end shortly after day
break Sunday based on the latest trends.
NBM probabilities for a 3 inches or more (advisory level) of snow
between 00z and 12z Sunday have been steadily increasing over the
last three cycles. They were around 50 percent for Southern CT and
the Lower Hudson Valley on the 13z Feb 5th cycle and are now around
80 percent on the 01z Feb 6th cycle. These probabilities have also
increased down to the coast and went from around 20 percent to
around 50 percent on the 01z cycle. NBM probabilities have also
increased for 6 inches (warning level) going from about 15 percent
to 50-60 percent inland. The probability for a 6 inch event at the
coast notably jumped from near 0 to about 15-20 percent. Based on
collaboration with neighboring offices and WPC, our latest official
snowfall forecast ranges from 2-4 inches Long Island and NYC metro
up to 4-6 inches with isolated amounts up to 7 in higher elevations
for interior NE NJ, Lower Hudson Valley and Southern Connecticut.
Adjustments to these totals are expected given that this is still 3
days out. A further north track would lead to lower snowfall totals
whereas a further south track could lead to higher totals down to
the coast. A brief period of freezing rain is possible, but have
left out of the forecast for now given some lingering uncertainties
with the depth of the surface cold as well as the potential warm
nose. Any freezing rain if it were to happen would be well after
midnight. Adjust
Dry conditions return on Sunday into Monday with high pressure
building over the region. The baroclinic/thermal gradient looks to
reside a bit further south than this week with several areas of
shortwave energy riding along this gradient. Guidance continues to
signal a series of low pressures passing to our south Tuesday and
potentially into Wednesday. Lots of questions remain with whether or
not it will be one main wave or broken up into different periods.
However, the chance is there for another wintry event mid next week.
The current model consensus was followed which gives a snow
solution. There is still room for this to trend a bit more
suppressed, which could lower precip amounts. For this reason, have
capped PoPs off at 50 percent for now.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Low pressure impacts the terminals into this afternoon. A cold
front passes late tonight.
A wintry mix is expected this morning with snow, sleet, and some
freezing rain. The mix will become plain rain 14-16z. Lower
Hudson Valley and Southern Connecticut terminals may stay a mix
or all snow a bit longer with a transition to plain rain by
early afternoon. The rain quickly ends by mid afternoon with
just lingering drizzle possible into early evening.
IFR conditions to start likely fall to LIFR late this morning
and early afternoon. LIFR will continue into the evening, mainly
in ceilings. There is a chance for LIFR fog, but confidence in
its coverage and duration is low at this time. Conditions will
improve tonight, becoming VFR late.
E-SE winds around 10 kt or less will shift to the E-NE late
morning and early afternoon. Winds may briefly go VRB before
becoming SW after 20-22z. Winds shift to the NW Friday morning
and become gusty, 25-30 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments are likely this morning for flight categories as well as
precipitation type changes.
Low chance for LIFR visibilities this evening.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: VFR. WNW winds G25-30kt.
Saturday: VFR during the day. Snow at night with IFR, changing to a
wintry mix late at night, especially near the coast.
Sunday: Light snow possible early inland with wintry mix near the
coast with IFR, then VFR.
Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sub-SCA conditions are expected this morning with a building sea
allowing for SCA conditions on the ocean by this afternoon and
evening. Increasing W and NW winds tonight and especially on
Friday behind a departing low will allow the expansion of SCAs
to the rest of the waters. Gusts will generally be 25-30kt,
though a gale force gust can`t be entirely ruled out on Friday
for the waters. Sub-SCA condition are then expected Friday night
and through at least Saturday.
SCA conditions are possible on the ocean Saturday night into Sunday
as low pressure impacts the waters. High pressure then returns with
a weak pressure gradient and conditions below SCA levels Sunday
night into Monday night.
&&
.HYDROLOGY...
There are no hydrologic concerns through the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 1 PM EST this afternoon for
CTZ005>012.
NY...Winter Weather Advisory until 1 PM EST this afternoon for
NYZ067>071.
Winter Weather Advisory until 11 AM EST this morning for
NYZ072>075-078-080-176>179.
NJ...Winter Weather Advisory until 1 PM EST this afternoon for
NJZ002-004-103>105-107.
Winter Weather Advisory until 11 AM EST this morning for
NJZ006-106-108.
MARINE...Small Craft Advisory from 6 AM to 6 PM EST Friday for ANZ331-
332-335-338-340-345.
Small Craft Advisory from 1 PM this afternoon to 6 PM EST
Friday for ANZ350.
Small Craft Advisory from 6 PM this evening to 6 PM EST Friday
for ANZ353-355.
&&
$$
SYNOPSIS...DS/MW
NEAR TERM...MW
SHORT TERM...MW
LONG TERM...DS
AVIATION...DS
MARINE...DS/MW
HYDROLOGY...DS/MW