011
FXUS61 KOKX 151159
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
659 AM EST Sat Feb 15 2025
.SYNOPSIS...
Deepening low pressure will move out of the Mid Mississippi Valley
today, passing to the northwest on Sunday and then to the north
Sunday night. A strong cold front will pass through behind the
low late Sunday afternoon into the early evening. Strong high
pressure drives into the middle of the country Tuesday into Wednesday
and gradually noses in. Low pressure then emerges out of the Gulf
of America and Southeastern US. This low strengthens as it
attempts to lift north along and just off the Mid Atlantic coast
Thursday. The low pulls away Friday with high pressure building
into next weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
A vigorous southern branch low will move out of the Mid
Mississippi Valley today, eventually phasing with northern
branch shortwave energy dropping across the Midwest tonight.
This will result in a rapidly deepening surface low that
approaches the eastern Great Lakes Sunday morning, sending a
warm front towards the area. At the same time, cold high
pressure over the area this morning weakens and dissipates east
of the area tonight. The combination of strong thermal forcing
moving into the area this afternoon and into tonight will allow
for overrunning precipitation to break out first as snow, then
transitioning to plain rain from south to north through the
overnight. However, while plenty of warm air moves in aloft, it
will take a bit longer for the low-level cold air across the
Lower Hudson Valley and interior souther CT to get scoured out.
There are some small timing differences with both the elevated
warm layer aloft and surface subfreezing air, but generally no
more than 1-2 hours. However, this could impact snow and ice
amounts up or down depending on the arrival of the warm air.
Typically this setup would favor the earlier scenario with a
low track to the west and weak high pressure.
Snowfall totals have been nudged up a bit across NYC and LI, but
still only looking at 1-2 inches before a changeover to rain this
evening. To the north and west where winter weather advisories
remain in effect, expect anywhere from 2 to 4 inches with a glaze
to two tenths of an inch of ice. The upper end of these ranges
will be closer to I-84 and some of the higher terrain areas
well inland.
After lows this morning generally in the 20s, temperatures will
be slow to rise due to increasing cloud cover and eventual
evaporative cooling from precipitation falling into a drier
airmass. Low-level winds will become onshore today form the SE
at less than 10 mph, another warming ingredient. Highs will get
into the lower and mid 30s this evening and will continue to
gradually warm up through the overnight. By daybreak, areas
well inland will be in the lower to mid 30s, with LI and the NYC
around 40.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Low pressure is forecast to be west of the area Sunday morning
with the associated warm front near or just south of LI. The
first shot of warm advection precipitation will lift to the
north and east with a secondary surge of warm advection as a
southerly LLJ approaches from the south, strongest to the south
and east of LI, with the potential for 75 to 85 kt just a few
thousand feet. Airmass will be strongly inverted and any mixing
of higher winds from aloft will likely not to happen until late
in the afternoon as the cold front approaches from the west and
the inversion erodes. With the warm front still in close proximity,
strong thermal forcing both in the warm sector and to the north
should allow for more a convective type of rainfall with showers
and possible thunderstorms. Confidence is low so for the time
being have left the mention of thunderstorms out. Rainfall during
this time will be moderate to occasionally heavy with the best
thermal forcing across eastern LI and SE CT. By the time the
cold front passes late afternoon/early evening, much of the area
is forecast to have received 1.5 to 2 inches of liquid equivalent,
with the highest amounts across LI and CT. There will likely be
plenty of ponding of water on areas roadways due to the
rainfall and snow melt. However, any flooding should be limited
to the minor nuisance variety with 6h FFG values generally over
2 inches. However, streams and small rivers in NJ could pose a
minor flood threat.
A high wind watch has also been issued for the entire area
Sunday night into Monday. Just ahead and behind the cold front,
there is the potential for wind gusts of 40-50kt, especially
with the pressure rises immediately behind the cold front. Winds
at the top of mixed layer will be around 50 kt, and on average
about 40 kt through the layer. Thus, high winds are possible
through the overnight, aided by strong cold advection and
cyclonic flow. Temperatures will fall back below freezing and
into the 20s by daybreak Monday.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
* Windy with the potential for strong winds on Monday.
* The potential remains and has increased some for a significant /
major winter storm in the Wed night - Thursday night time frame.
Low pressure pulls north into Eastern Canada and the Canadian
maritimes Monday into Monday night. A strong W wind will be the main
story to begin the week. The pressure gradient will begin to
decrease and the winds gradually subside Monday night into Tuesday
morning. Temperatures will be running about 7 to 10 degrees below
normal for Mid Feb for Monday into Monday night. Wind chills by
Tuesday morning will be down into the single digits to around zero
across the northern most sections. The heart of the cP air mass
arrives for Tuesday into Tuesday night. The winds will be lighter so
it may not feel quite as cold, but temperatures will continue to run
well below average.
Then all attention turns to the deep south as low pressure emerges
out of the Gulf and tracks across No. Florida and along the SE coast
Wednesday into Wednesday night. Much of the global guidance is
suggestive of a Classic Miller A type storm. Ensemble sensitivity /
cluster analysis does hint at some differences in how deep and south
the northern branch upper level low gets, along with some difference
in phase / speed, and thus timing differences. What is notable is
that most of the 12z 2/14 QPF ensemble clusters get the half inch
QPF line into the coastal plain. What is different from past
scenarios this winter season is that the suppressed Pacific or
southern branch energy will not get locked up in any type of SW US
upper level low as any suppressed energy in the Pacific / Southern
branch will come out and be intact as it gets east. Questions remain
as to when and exactly how the northern closed low interacts with
the suppressed Pacific branch energy. The 0Z 2/15 ECMWF and UKMET
operational runs bring a major snow event to the I95 corridor and
our area. The CMC also brings a significant winter storm to the area
and is furthest west which is suggestive at some mixing along the
coast. The GFS operational run struggles to bring the energy
together, which can be a bias of the model. However, the EC-AIFS (AI
model) and the ICON is doing something similar, but the ICON is less
pronounced with the eastward position and track. However, most of
the eastward guidance is suggestive of strong PVA along the coastal
plain suggesting that the sfc features could be placed too much to
the east, especially considering the 500 mb features. The various
ensemble systems overall (EPS, GEPS, and to a lesser extent the
GEFS) are suggestive of a significant east coast storm. There
remains a big discrepancy in the amount of deepening and position of
the sfc low tracks with respect to the various ECMWF
/ GFS ensemble members from the 0z 2/15 run. One thing to note is
that there is no discernible downstream blocking, and thus the storm
system is not expected to stall and should remain fairly
progressive. In any event, this will be a hot topic over the
upcoming days.
Behind the system expect strong winds and cold / dry advection as it
pulls away late Thu night into Friday. This should lead to dry and
cold conditions to close out the week.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
High pressure moves offshore as low pressure approaches later today
and passes through tonight into early Sunday.
VFR through this morning. Cigs and vsbys lower this afternoon into
this evening as snow develops. MVFR prevails towards 20z for the
city terminals, with vsby as low as 3/4SM possible in pockets of
steadier snow. Snow transitions to rain along the coast in the
evening and inland overnight with KSWF and KHPN having a transition
to freezing rain. A wintry mix remains at KSWF for the entire
overnight Sat into early Sun AM. Overall cigs and vsbys will remain
low with IFR and pockets of LIFR late this evening and into Sunday
morning.
Light winds give way to a developing southeasterly flow under 10 kt
by this afternoon. E to SE winds will prevail with some increase in
speed this evening into tonight to around 10 kt at most terminals,
with a few terminals getting a bit above 10 kt towards late evening.
Airport snow accumulations (inches): KJFK 1-2, KLGA 2, KEWR 1-2,
KTEB 2, KISP 1-2, KBDR 2-4, KGON 2-4, KHPN 2-3, KSWF 3-4 .
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible with timing uncertainty for flight category
changes as snow moves in this afternoon into the evening.
.OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sunday: IFR or lower with rain. A chance of freezing rain at KSWF
early in the morning. LLWS expected, for the city and eastern
terminals. S winds with gusts increasing in the afternoon,
potentially 25-40 kt late in the day. Gusts could peak to 45 to 50kt
in the evening with W winds.
Monday: VFR with W winds G35-40kt.
Tuesday: VFR with W winds G25 kt.
Wednesday: VFR daytime. Chance of snow towards evening and at night
with possible IFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
High pressure over the waters this morning weakens and then
dissipates to the east through tonight. A storm system will
impact the area with a strengthening southerly flow on Sunday,
followed by strong west winds Sunday night. A gales watch has
been posted for all waters Sunday afternoon through the first
half of Monday night. There could even be occasional gusts up to
storm force. Seas will build to 5 to 8 ft on LI Sound and 10 to
18 ft on the ocean waters overnight Sunday.
Gale conditions across all waters on Monday with occasional storm
force gusts in the wake of a storm moving through the Canadian
maritimes. High ocean seas of 7 to 14 ft are expected through the
day Monday. Seas and winds then gradually subside Monday night with
gale conditions likely for a good portion of the night. Conditions
then decrease to small craft on Tuesday with ocean seas down to
around 4 to 7 ft. Sub advisory conditions arrive Tuesday night, with
ocean seas down to around 2 to 3 ft by Wednesday.
&&
.HYDROLOGY...
No hydrologic impacts are anticipated from this weekend`s storm
system despite the fact that 1.5 to 2 inches of liquid is expected
across the area. Thereafter no hydrologic impacts are anticipated
through the remainder of the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from noon today to 7 AM EST Sunday for
CTZ005>008.
High Wind Watch from Sunday evening through Monday afternoon
for CTZ005>012.
Winter Weather Advisory from noon today to 1 AM EST Sunday for
CTZ009>012.
NY...Winter Weather Advisory from noon today to 7 AM EST Sunday for
NYZ067-068.
High Wind Watch from Sunday evening through Monday afternoon
for NYZ067>075-078>081-176>179.
Winter Weather Advisory from noon today to 1 AM EST Sunday for
NYZ069>071.
NJ...Winter Weather Advisory from noon today to 7 AM EST Sunday for
NJZ002.
High Wind Watch from Sunday evening through Monday afternoon
for NJZ002-004-006-103>108.
Winter Weather Advisory from noon today to 1 AM EST Sunday for
NJZ004-103>105.
MARINE...Gale Watch from Sunday afternoon through Monday evening for
ANZ331-332-335-338-340-345.
Gale Watch from Sunday morning through Monday evening for
ANZ350-353-355.
&&
$$
SYNOPSIS...JE/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...JE
AVIATION...JE
MARINE...JE/DW
HYDROLOGY...JE/DW