000
FXUS61 KOKX 102057
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
357 PM EST Sat Feb 10 2024
.SYNOPSIS...
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A cold front passes through tonight, with weak high pressure
left in its wake Sunday through Monday afternoon. Deepening
low pressure approaches from the southwest Monday night and
will pass south and east of Long Island on Tuesday. High
pressure returns Wednesday into Thursday before a Clipper low
passes through Thursday night into Friday. High pressure may
briefly return next Saturday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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A cold front shifts through the forecast area tonight. The front
will be somewhat weak and slow as the flow aloft remains fairly
flat. Best chances of showers will be over Orange County and
surrounding areas into early this evening where there is some
residual CAPE, but chances of showers will exist across the
entire area. The cold front will be south and east of us by
daybreak, but we`ll be left with mid and high level clouds. This
cloud cover will help promote low temperatures in upper 30s
inland and 40-45 for coastal areas, which are more typical of
daytime highs this time of year.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
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Weak surface high pressure will be in control of the weather through
this period with the flow aloft remaining zonal. Although it will be
dry, it`ll remain on the cloudy side as mid and high level clouds
extend in from the south. Perhaps some thinning out heading toward
the end of the day. It`ll be relatively mild in spite of this with
high temperatures near 50 for NYC metro and mid to upper 40s
elsewhere. Looks like clouds diminish further during Sunday night,
and this will help allow low temperatures fall into the upper 20s
for the northernmost zones and Pine Barrens, with 30s everywhere
else.
Not much change for Monday as we remain dry with highs again mostly
45-50 across the area. The main difference will likely be with the
cloud cover. Expecting more in the way of clouds in the afternoon vs
the morning this time around.-- End Changed Discussion --
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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A winter storm will impact the region Monday night into Tuesday.
* A Winter Storm Watch has been issued for Orange, Rockland, Putnam,
N Westchester, W Passaic, W Bergen, N Fairfield, N New Haven, N
Middlesex, and N New London 06z Tuesday through 23z Tuesday.
* A plowable, advisory level snow is possible for Southern
Westchester, coastal CT and portions of NE NJ west of the I-95
corridor.
* Uncertainty remains on the track of the deepening low pressure and
timing of transition to snow in the NYC metro and Long Island
corridor.
* Temperatures will be near to slightly below normal.
* Mainly dry weather expected Tuesday night through the beginning of
next weekend with a quick moving clipper system possible Thursday
night into Friday.
Confidence continues to increase that a fast moving winter storm
will impact the region Monday night into Tuesday. The modeling is
still showing quite a range of solutions regarding the track of the
deepening low pressure. However, the main features in the middle and
upper levels are continuing to get better resolved. Differences
arise with the strength of the southern stream shortwave and the
confluent flow over the northeast. The modeling may fluctuate over
the next day or so as the northern stream may take some time to get
fully resolved. The models and ensembles (GFS, ECMWF, GEFS mean, EPS
mean) that have a stronger, closed, and more compact 500 mb low have
the surface low tracking further north towards western PA and then
transferring off the Delaware, Southern NJ coast late Monday night
and then south and east of Long Island Tuesday morning. Other
modeling and some ensemble members show a less compact 500 mb low
and more confluence do not track the primary as far NW yielding a
surface low track further south off the Middle Atlantic on Tuesday.
In either case, there is consistency that the northern and southern
branches of the polar jet will not phase until the system gets east
of the area.
The amount of cold air for the system to work with remains a
concern, but there is enough evidence for inland areas to have
sufficient cold air to work with for predominately snow to fall late
Monday night into Tuesday. Closer to the coast the boundary layer is
marginal with temperatures likely starting out in the upper 30s to
around 40 Monday night and then slowly falling into Tuesday morning
as the system deepens and starts to pull down some slightly colder
air. Dynamical cooling will likely play a roll as the system wraps
up Tuesday morning, but its always a question of how much of that
will lower surface temperatures as one nears the NYC metro and Long
Island. There is some concern that the dynamics within the cold
conveyor belt around the NW side of the low will be sufficient to
cool the boundary layer just enough for a period of snow at the
coast. The question remains on the intensity and how will much will
accumulate.
Based on collaboration with neighboring offices, have issued a
Winter Storm Watch for the interior where confidence is highest in
seeing warning criteria being met. This is also where there is the
greatest potential for heavy snow banding to coincide with colder
temperatures. Ensemble probabilities including the latest NBM paint
about a 60-70 percent chance of seeing greater than 6 inches in this
region. Further south, confidence decreases especially towards the
coast. Probabilities along the coast are lower indicating the region
with greatest uncertainty due to the aforementioned factors above.
NBM probabilities for an Advisory level snow are around 30 percent
near the coast. Think this may be a bit high given the marginal
temperatures and modeling generally biasing towards a 10:1 ratio. If
the further south low tracks end up verifying, then snow amounts
down to the coast may end up higher.
The latest snowfall forecast has 6-8 inches in the watch areas with
some higher amounts closer to 10 in the higher elevations down to a
3-5 inch heading further south towards the CT coast and then 1-2
inches in the NYC metro and Long Island. A reasonable worse case
scenario in this region of around 4-6 inches if colder scenarios,
further south scenarios verify. A reasonable worst case scenario
reaches around a foot well inland.
Gusty winds are possible with the system, 25-35 mph, strongest near
the coast. Dry conditions will return Tuesday night.
There was not much change with the rest of the long term period. The
main story will be temperatures slightly below normal to normal the
rest of the week into the first half of next weekend. Mainly dry
conditions are forecast with a fast moving clipper system passing
through the northeast Thursday night into Friday.-- End Changed Discussion --
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
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A cold front will pass through tonight. Weak high pressure will then
follow in its wake through Monday afternoon.
Mainly VFR. Can not rule out a brief shower ahead of cold fropa
early this evening, even a tstm info KSWF. Timing should be across
the lower Hudson Valley from 22Z-24Z, NYC metros/KBDR from 23Z-01Z,
and KISP/KGON from 00Z-02Z.
SW-WSW flow less than 10 kt may briefly back SW-S before fropa (not
indicated in TAF). Winds shift WNW less than 10 kt after fropa, and
eventually become NW late tonight. NW flow around 10 kt expected
after 13Z Sunday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Brief -SHRA possible from about 23Z-01Z with cold fropa. Winds could
also back more SW-S during this time frame.
OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
Sunday...VFR.
Monday...Mainly VFR.
Monday night...IFR or lower cond likely. At KSWF/KHPN, rain or
a snow/rain mix, changing to all snow after midnight.
Elsewhere, rain possibly mixing with snow late. NE winds 10-15
G20-25 kt late, highest NYC metro/coast.
Tuesday...IFR or lower cond likely. Precip changing to all snow
by late morning. Snow tapering off from W-E during the
afternoon, with cond possibly becoming VFR late. NE-N winds
15-20 G25-30kt, becoming NW in the afternoon.
Tuesday night through Wednesday night...VFR. NW winds
10-15G20kt daytime, and 10-15G20kt at night.
Thursday: Mainly VFR. W winds 10-15G20kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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A cold front will move through the waters tonight, but winds will
remain below advisory thresholds with its passage. An easterly swell
will maintain seas around 4 ft on the ocean, and maybe waves reach 5
ft at times, but prevailing conditions would preclude a SCA.
Swell/seas slowly subside a little on Sunday, and winds across all
waters are expected to be at 10kt or less with weak high pressure
over the area. Tranquil conditions then continue into Monday.
NE winds increase Monday night ahead of an approaching deepening low
pressure system from the southwest. The low then passes just south
and east of the ocean waters on Tuesday. This will allow winds to
potentially reach gales on the ocean on Tuesday. In collaboration
with neighboring offices, have issued a gale watch for Tuesday.
Otherwise, SCA conditions are likely late Monday night through
Wednesday. Winds behind the low also look strong to help keep the
potential for SCA conditions going. SCA winds may persist into
Thursday on the ocean waters, but ocean seas should subside below 5
ft Wednesday night.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic issues expected at this time.
&&
.TIDES/COASTAL FLOODING...
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Minor coastal flooding will be possible across multiple high cycles
through Monday night. Have issued a long-running statement for the
western Sound as water levels with each high tide may touch or
barely surpass thresholds at Stamford and/or Bridgeport. Advisories
will be issued for the next two AM high cycles for S Nassau.
Per blend of bias-corrected Stevens NYHOPS/ETSS/ESTOFS guidance, a
storm passing through Mon night-Tue has potential to produce
moderate flooding on the western Sound, the Long Island south shore
bays of SW Suffolk/Nassau, and lower NY Harbor, and minor flooding
elsewhere. Winds will be backing N around the time of high tide
which could keep levels from touching moderate benchmarks on the
Sound/Harbor. Have not yet issued coastal flood watches for this
time frame because of that, and also to avoid confusion with ongoing
earlier minor flooding.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Winter Storm Watch from late Monday night through Tuesday
afternoon for CTZ005>008.
NY...Winter Storm Watch from late Monday night through Tuesday
afternoon for NYZ067>070.
Coastal Flood Advisory from 7 AM to 11 AM EST Sunday for
NYZ179.
Coastal Flood Advisory from 8 AM to noon EST Monday for NYZ179.
NJ...Winter Storm Watch from late Monday night through Tuesday
afternoon for NJZ002-103.
MARINE...Gale Watch from Tuesday morning through Tuesday afternoon for
ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/DS
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...DS
AVIATION...BG
MARINE...JC/DS
HYDROLOGY...JC/DS
TIDES/COASTAL FLOODING...BG