803
FXUS61 KOKX 010141
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
841 PM EST Fri Jan 31 2025
.SYNOPSIS...
-- Changed Discussion --
A frontal wave will move across the area tonight, followed by a
late cold frontal passage. High pressure will then build in
from the Great Lakes on Saturday, while low pressure deepens
over the western Atlantic. A warm front then approaches on
Sunday and passes through during Sunday night. The trailing cold
front from this low pressure system passing to the north will
pass through Monday night, followed by high pressure through
early Wednesday. Another frontal system will then impact the
area later on Wednesday into Thursday. High pressure is expected
to follow on Friday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
A frontal wave will pass through the area the first half
tonight, followed by a northern branch cold frontal passage
during the early morning hours. Upward forcing associated with
the low, including synoptic scale lift from an upper jet streak
will bring rain across the area. The higher rain amounts will be
generally east of the city. The rain will end from NW to SE,
clearing far SE CT and eastern LI by around 5 AM.
Another issue is the fog. Light winds and small dewpoint
depressions will lead to areas of fog mainly away from the city.
Patchy dense fog will be possible mainly outside of the NYC
metro.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
High pressure will be building in out of Canada through the day
Saturday, bringing in a colder air mass. It`ll be sunny, and high
temperatures will be slightly below normal in the 30s across the
area. Breezy conditions, particularly in the morning will add to the
chill, making it feel like it`s only in the 20s.
Winds then diminish Saturday night as the center of high pressure
shifts to our north and the pressure gradient weakens. Mainly clear
conditions and light to calm winds will allow for radiational
cooling, with low temperatures dropping into the single digits
across the northernmost zones. Teens for most other locations,
except low 20s in the city.
For Sunday, looks like it should be dry most of the day. Overrunning
precip will however advance from the west ahead of a warm front.
This front is in association with a quick-moving low pressure system
well to our north. Snow will be possible towards late in the day
north of the city. Snow chances then become more likely Sunday night
north of the city as the warm front moves through, with the highest
chances being over SE CT. Looks like it should be coming to an end
by the time a warm nose pushing in could result in a wintry mix late
at night. Snow amounts of an inch or less anticipated - highest
generally across the northernmost zones. For the city, LI and the
urban corridor of NE NJ, precip chances are capped at chance, and it
should be warm enough for rain during the whole event.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A nearly zonal flow will feature some timing issues with a midweek
storm system that will impact the area. The latter of which will be
driven by kink in the flow late in the week as an amplifying
shortwave trough drops across the Great Lakes Thursday and across
the Northeast on Friday. Before then though, a cold front will pass
through the area Monday night as low pressure passes well to the
north. This looks to be uneventful with perhaps an isolated shower.
More importantly, it will return the area to temperatures closer to
normal for early February and potentially set the stage for some
wintry weather later in the week. High pressure briefly returns
Tuesday into early Wednesday.
Where there are issues that still need to be resolved are with low
pressure emerging from the Central Plains midweek and the
overrunning precipitations that breaks out well in advance of the
associated warm front. The parent low likely tracks west of the area
with warm air surging in aloft and snow or a rain/snow mix the onset
that goes over to rain Wednesday night. A confluent flow between the
two branches of the polar jet lifts out to the northeast on
Wednesday. How quickly that happens will determine the extent of
cold air and how quickly it erodes. There is high confidence that
enough warm air moves in aloft for a changeover to rain, but an
extended period of freezing rain is possible north and west of the
NYC metro Wednesday night. The NBM still is showing quite a
temperature spread for the midweek system with box and whisker plots
showing as much as 20 degree spreads between the 25th and 75th
percentiles. The deterministic is very close to the median during
this time. Expect all rains on Thursday before it comes to an end
late Thursday night following a cold frontal passage. Temperatures
in the warm sector Thursday may get into the 50s, but falling back
into the 40s Friday. Thus, a period of quickly changing weather.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
A frontal wave will move across the area tonight, followed by a
late cold frontal passage. High pressure will then build in
from the Great Lakes on Saturday, while low pressure deepens
over the western Atlantic.
Widespread IFR/LIFR conditions will persist through the early
morning in rain and fog. A cold frontal passage by daybreak
will result in improving conditions and a return to VFR by 13Z
for all locations.
Winds will be generally light and variable until the cold
frontal passage after 06Z, followed by increasing N/NW flow.
Expect winds to increase to around 15kt with G20-25kt. A few
higher gusts up to 30 kt possible.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for timing of category changes. VFR conditions
could return earlier based trended in the latest guidance.
Timing of N/NW winds gusts toward daybreak may vary by 1-2
hours.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
Saturday Night: VFR. NW winds 10-15G20-25kt early in the evening,
then diminishing.
Sunday: VFR during the day, a chance of MVFR or lower conditions at
night in rain and/or snow.
Monday-Tuesday: VFR.
Wednesday: MVFR or lower in developing rain and/or snow.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Will need to monitor for the potential of a dense fog advisory at
least during the evening hours tonight based on local weather cams
and with the expectation that winds won`t increase and shift north
until the overnight hours. Otherwise, the SCA has been extended on
the ocean into Saturday night as a lingering swell is expected to
keep seas elevated. Elsewhere, have issued a SCA for the daytime
Saturday for gusty northerly winds as building high pressure causes
a tightening pressure gradient. Sub-advisory conditions then prevail
for Sunday through Wednesday. The only exception would be marginal
SCA gusts on the ocean possible ahead of a cold front Monday and
behind it Monday night into Tuesday.
&&
.HYDROLOGY...
There are no hydrologic concerns at this time.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 AM to 6 PM EST Saturday for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 6 AM EST Sunday for ANZ350-353.
Small Craft Advisory until 1 AM EST Sunday for ANZ355.
&&
$$
SYNOPSIS...JC/DW
NEAR TERM...JC/DW
SHORT TERM...JC
LONG TERM...DW
AVIATION...DW
MARINE...DW/MW
HYDROLOGY...DW/MW