842
FXUS61 KOKX 042348
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
648 PM EST Sat Jan 4 2025
.SYNOPSIS...
The region will remain between low pressure to the north and high
pressure to the south through the rest of the weekend. A quick
moving low pressure system passes through the Mid Atlantic on
Monday and offshore Monday night. Behind it, strong Canadian
high pressure builds in from the west through late next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
Gusts have come down considerably from earlier in the day when
some locations achieved advisory levels. Still though, expecting
gusts of 20 to 30 mph through the overnight due to a strong
pressure gradient between high pressure to the southwest and
deepening low pressure over the western Atlantic heading up
toward New Foundland.
For temps, went with the NBM but made some local adjustments.
Wind chills overnight in the teens and single digits.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Some sct-bkn cu should develop during the day with steep llvl lapse
rates. Continued windy, but speeds aloft are modeled to be less than
Sat, so gusts should generally be blw 35 mph. Stuck with the
NBM for highs which yields mainly low to mid 30s.
As the next sys approaches from the w, increasing clouds can be
expected Sun ngt, particularly late. A few flurries may break out
extreme swrn sections by sunrise, otherwise it is expected to be dry
per the model consensus. Winds will diminish considerably as the
pres grad relaxes. The NBM with the usual adjustments was used for
low temps, which produces numbers in the teens and 20s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Points:
* Low pressure passes to the south across the Mid Atlantic states on
Monday with light snowfall possibly grazing southern portions of
the forecast area. The trend continues toward little or no
snowfall.
* Cold, windy, and predominantly dry conditions expected through the
upcoming week.
A well advertised low pressure system will pass to the south of the
area across the Mid Atlantic states on Monday. The trend the last
24h has been for a slight southward adjustment and a downward trend
in amounts for what would be a light snowfall event for southernmost
areas of the forecast area. Global models and their ensembles remain
in very good agreement with low probabilities for an advisory level
snowfall event (3 inches or more) with the LREF Grand Ensemble
(GEFS, GEPS, EPS) and NBM less than 10% for an inch or more for
southernmost portions of the NYC metro (which has the highest
probabilities). For greater than inch, probabilities are about 20%
and 40%, respectively. Bottom line here, everything is pointing to
little or no snow accumulation for a small portion of the forecast
area. This still needs to be watched due to the interaction of
multiple pieces of energy in the northern branch of the polar jet
across eastern Canada. A subtle shift of the low track north would
increase amounts, but by no means would this be a significant event
for the tri-state area.
The bigger news will be an anomalously cold airmass and gusty W/NW
winds Tuesday through Thursday with temperatures about 10 degrees
below normal. NBM box and whisker plots show the deterministic highs
at or above the 75th percentile through the period, but closer to
the median (50th) for lows. In addition, 12Z global operational 2m
temperatures support a colder forecast.
Thus, blended the NBM with its median for highs to get it a bit
lower.
The 12Z operational GFS and to a lesser extent the ECMWF, show a
potential late week storm system next weekend. This is of course
just something to watch and there will likely be many iterations
before locking in on something more definitive.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
VFR with the region remaining between low pressure to the north and
high pressure to the south.
W flow 15-20 kt with gusts 25-30 kt may decrease slightly late
tonight, then resume by 14Z and continue til 22Z-23Z. A few gusts
over 30 kt are possible in the afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected.
OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday night: VFR with diminishing NW winds.
Monday: Chance of light snow at the NYC metro
terminals/KHPN/KISP/KBDR with MVFR cond likely, IFR possible.
Little accumulation expected, with worst case accumulation an inch
at the NYC metros and KISP.
Tuesday through Thursday: VFR. NW winds 15-20kt with daytime gusts
25-30 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
It will continue to be windy for the rest of the weekend. The gale
wrng has been extended thru tngt for all waters. When the gale ends,
a SCA will be needed thru at least Sun eve, particularly on the
ocean where seas will take some time to subside. Because the SCA was
already up for Sun, it was maintained to avoid poor messaging.
There is the potential for a prolonged W/NW gale across all waters
Tuesday into Thursday due to a strong pressure gradient between
building high pressure and low pressure over eastern Canada.
&&
.HYDROLOGY...
No significant hydrologic issues anticipated through the end of
next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until 6 AM EST Sunday for ANZ331-332-335-338-340-
345-350-353-355.
Small Craft Advisory from 6 AM to 7 PM EST Sunday for ANZ331-
332-335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...JMC/DW
NEAR TERM...JMC/DW
SHORT TERM...JMC
LONG TERM...DW
AVIATION...JT
MARINE...JMC/DW
HYDROLOGY...JMC/DW