000
FXUS61 KOKX 040521
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1221 AM EST Thu Jan 4 2024
.SYNOPSIS...
Two weak frontal systems, one passing to the north, and the other
passing to the south, will affect the region late tonight into
Thursday. High pressure starts to build in to the west Thursday
night and remains in control into Friday night. Low pressure
will pass south and east of the region late Saturday into
Sunday, bringing rain and snow to the region. A deep low may
pass west of the area by the middle of next week, producing
stormy conditions across the Tri-State Region.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
The forecast has been adjusted to increase the cloud cover for
the rest of the night, and consequently, adjust the low
temperature forecast upward by a little in most areas. Rest of
the forecast is on track.
Phasing northern and southern stream systems will affect the
region by late tonight as a full latitude upper trough moves
toward the east coast. Both surface systems will be rather weak
moving into the area late tonight, with the southern system
moving close to the area by 11Z Thursday. So, will have an area
of slight chance probabilities to the north, and then another
area of slight chance to the south, with the better chances
remaining off shore. Cold air will be in place for snow showers
across the land and rain/snow showers off shore.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
The upper trough will remain progressive during Thursday,
moving off shore 21Z Thursday to 00Z Friday. Again, will keep
just slight chances for precipitation across the southern land
areas. With day time insolation snow showers may mix with or
briefly go over to rain showers before ending late in the day. A
weak cold front will the northern passes to the east by early
Thursday evening.
The southern stream system begins to deepen well to the south
and east late Thursday through Thursday night as a strong
1030/1031 high builds into the area from the west. A period of
gusty northwest winds becomes likely late Thursday into
Thursday night, and then diminish as the surface high builds
toward the region.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
No major changes with the 12Z model cycle with the general idea of
the low for this weekend. There remain some differences wrt the
exact track however. The ECMWF is the furthest N, and looks like an
outlier when compared to the GFS and GEM, which are further S. The
GFS Ensemble mean is even further S, so the fcst has been tweaked
towards a more sly, colder soln.
The models are often too warm with sfc temps this far out,
particularly on the cold side of the sys. Couple this with a spread
in tracks, and the NBM looks too warm attm. The end result could be
warmer if the track ends up farther N, but based on the GFS ensemble
and the low not getting to 40N, blended the NBM10 percent with the
CONSALL for sfc temps late Sat thru Sun.
Based on the expected nely winds, a coastal front would likely
develop across sern LI and possibly into sern CT, adding another
layer to the temp complexity. This boundary should delineate a
mainly all rain event from snow or a mixed event.
The low is progged to get around 999 by 12Z Sun per the GFS, but
there is some model spread in the intensity as well. The GEM appears
to be the deepest, getting down to around 988. This signals that a
big wind event is not expected attm. The deepest low soln would
likely yield peak gusts around 40kt for sern areas.
For snowfall, in general this looks like a 4-8 inch with locally
higher amounts sys where it remains all snow N and W of NYC, 3-6
most of the area, and 2-4 or less much of LI and the ern CT coast.
Again this is all subject to change, with a track to the N bringing
more rain and a track further S beginning to limit pcpn amounts.
Will add a mention in the HWO for the 4-8 inch zone.
Most of the area should change over to periods of mainly light snow
on Sun as the low pulls away.
Dry by Sun ngt, and remaining dry thru Mon ngt with a 1030s high
pres ridge passing thru the area. Should be cold Mon ngt with this
setup, especially if there is any snow on the ground.
The next storm is late Tue thru Wed. The models have been consistent
with this event even this far out. A 970s low tracking W of the
region is the current prog. This would produce a high wind event,
along with some hvy rainfall. In addition, there could be some fzra
across the interior at the onset late Tue into Tue ngt. The models
may be having a difficult time handing any CAD with the sys. The MEX
at MGJ is close to 15 degrees warmer than the NBM for highs on
Tue. Trended the fcst colder, particularly across the interior, as
a result.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
A cold front passes through late this morning into early afternoon.
VFR, except mostly MVFR through at least the pre-dawn hours at KSWF.
W to NW winds under 10 kt through the night. Winds bcmg more NW and
gusty late this morning. Stronger NW winds in the afternoon. A few
gusts may exceed 30 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Peak occasional gusts at or above 30 kt possible after around 19Z.
OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
Late tonight: VFR. NW G20kt possible.
Friday: VFR. Occasional NW G20kt possible for the AM push.
Saturday: VFR becoming IFR or lower Sat ngt in snow and/or
rain. Increasing E/NE winds with gusts 25-35kt at night.
Sunday: Rain/snow ending as snow. IFR or lower possible. Winds
becoming N with gusts up to 20kt possible in the morning.
Monday: VFR.
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 tonight into early
Thursday as a weak pressure gradient will be across the waters
as one weak low passes to the north, and another passes to the
south.
As colder air moves in behind the northern system`s cold front,
and high pressure builds to the west, with the southern system
deepening, northwest winds and gusts will increase quickly
Thursday to SCA levels across all the forecast waters. And ocean
seas will then build to SCA levels Thursday night. The potential
for marginal gale force gusts in the ocean waters has diminished
and will no longer mention in the HWO. A SCA has been posted for
all the waters beginning Thursday afternoon. Conditions will
quickly improve late Thursday night as high pressure builds in
from the west, and will the advisory across all the waters by
11Z Friday. There is a chance that SCA gusts continue into early
Friday morning across the eastern ocean, and possibly eastern
Long Island Sound, and the advisory may be extended.
Once SCA conditions end no hazards are expected through the
remainder of Friday.
Gales are possible over the weekend, especially on the ocean, as low
pres tracks S and E of the area. The best window is Sat ngt into
Sun. Winds and seas subside Sun ngt and Mon. Significant impacts are
possible late Tue.
&&
.HYDROLOGY...
No hydrologic impacts are expected thru this weekend attm. Impacts
possible for late Tue into Wed with deep low pres passing W of the
area.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 6 AM EST
Friday for ANZ331-332-335-338-340-345-350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/MET
NEAR TERM...JC/MET
SHORT TERM...MET
LONG TERM...JMC
AVIATION...JC
MARINE...JMC/MET
HYDROLOGY...JMC/MET