000
FXUS61 KOKX 161612
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1112 AM EST Tue Jan 16 2024
.SYNOPSIS...
Low pressure passes east of Montauk today. High pressure builds
in from the south and west midweek, sliding offshore Thursday.
Low pressure then develops off the Carolina coast Thursday
night, passing east of the region Friday. High pressure returns
this weekend.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
-- Changed Discussion --
Winter weather advisory goes until 7pm this evening for a
larger part of the area than before. Eastern Suffolk is the only
location not going until 7pm with winter weather advisory for
the CWA. The precipitation has transitioned to mostly freezing
rain along the coast with some potential for sleet to mix in
from time to time.
SE Suffolk was allowed to expire at 10am because temperatures
have risen there into the mid 30s, allowing for precipitation
type to be plain rain. NE Suffolk has temperatures around
freezing but expect a transition to mainly plain rain this
afternoon. For NE Suffolk, winter weather advisory goes until
1PM this afternoon.
For the rest of the forecast region, temperatures will be mostly
at or below freezing. Marginal locations such as Western Suffolk
and Nassau, feel there will be quite a few locations that remain
at or below freezing to warrant the extension of the winter
weather advisory , even more so for Southern New London CT. This
is considering the latest HRRR precipitation and NAM
precipitation forecasts as well as the HRRR temperatures. Feel
the HRRR is too fast with the movement of the rain/snow line to
the north and west. Feel temperatures will remain a few degrees
colder than the HRRR especially going farther north and west.
Slight increase in ice accumulation forecast along the coast.
Storm total ice accumulations still remain below a tenth of an
inch. Additional snowfall accumulations less than 1 inch for
much of the area, and this is looking to be primarily across the
interior areas.
Also, latter half of this afternoon, temperatures are forecast
to lower more from NW to SE, with column cooling and surface to
7-8 kft still has much moisture. Looking for snow to redevelop
and allow for snow to mix back in from west to east. This will
be pretty brief for Eastern Suffolk but longer farther west.
The refreezing will cause untreated surfaces to become icy and
slippery especially for those locations that had plain rain
earlier.-- End Changed Discussion --
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
-- Changed Discussion --
Cold with temps below freezing through Wednesday. Icy surfaces
tonight for anywhere that is untreated making for slippery
conditions. Also, winds not too gusty so while some moisture
will dry up, still think there will be many locations with
residual moisture and snowmelt that will refreeze.
Winds chills tngt in the single digits for the entire area.
Winds chills don`t get out of the teens on Wed with a brisk W
wind. Mainly clear with a few high clouds potentially coming in
by the end of the day Wed.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Some slight temperature moderation likely takes place Thursday
and Thursday night in advance of the next system as heights rise
aloft with west to east zonal flow.
A coastal low is expected to develop off of the Carolina coast
Thursday night with the southern branch of the jet stream. This will
then track north-northeast up the east coast in the Atlantic on
Friday then eastward out to sea on Saturday as it passes to our
southeast. With cold air in place, snow is likely Friday into
Saturday with this system. The general pattern remains the same with
most 12Z guidance, but solutions vary in terms of exact track and
magnitude to the coastal low. This will change the outcome of total
snowfall we see. For now, most solutions would give us is system.
For now, NBM probabilities hold a 50% chance of 1", 30-40% chance of
2" and a 20% chance for 3" or more. For now, expecting a prolonged
light snowfall event.
Regardless of the outcome of this system, in its wake the coldest
air mass of the season since last February is expected. In fact,
much of the region away from the coast may have to wait until early
next week to see the temperatures climb above freezing. The coldest
day appears to be Saturday, when 12Z global ensemble means
(including GEFS, EPS, CMCE) prog 500 mb heights 25-30 dam below
normal as the trough axis swings through. At this time, highs on
Saturday top out in the 20s, and perhaps the teens across the
interior if colder guidance is realized. With a blustery NW wind,
wind chill values could fall into the single digits or below zero at
points Friday and Saturday night.
A strong ridge nudges in from the west on Sunday as the trough exits
farther to our east with surface high pressure building in from the
southwest. It effects likely won`t be fully realized until Monday,
since Sunday still has highs in the low-30s to upper-20s.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Developing low pressure off the Carolina coast passes just east
of the region through this afternoon. High pressure begins building
in from the southwest tonight.
MVFR or IFR with light snow, localized LIFR possible. Improvement
to VFR in the late afternoon or early evening.
The light snow changes to a wintry mix across central/eastern
Long Island through mid morning and works its way north and
west towards the NYC metro terminals toward 16z. Potential for
some freezing rain with this wintry mix, but duration and
intensity remain uncertain. Light rain expected for a time at
KISP and KJFK beginning by late morning or early afternoon.
Lower Hudson Valley terminals remain predominately snow.
Southern CT terminals may see a wintry mix late morning and
early afternoon. The precip tapers off in the afternoon and
could end as a brief period of snow or mix.
A light NW flow under 10 kt persists thru about midday, then
gradually shifts toward the N and then NE this afternoon and
evening. Wind speeds increase to around 10 kt late morning into
the afternoon. NW flow increases further late afternoon, with
20-25 kt gusts developing by 00Z Wed, lingering into the overnight.
Total snow accumulations...
KJFK/KISP/KGON: 2-3"
KLGA/KEWR/KTEB/KHPN/KSWF: 3-4"
In addition, a glaze of ice is possible this morning.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Uncertainty with timing of precip type changes through 18Z.
Sleet and freezing rain are possible through 18z.
The afternoon KJFK haze potential is YELLOW, which implies slant
range visibility 4-6SM outside of a cloud.
The afternoon KLGA haze potential is YELLOW, which implies slant
range visibility 4-6SM outside of a cloud.
The afternoon KEWR haze potential is YELLOW, which implies slant
range visibility 4-6SM outside of a cloud.
OUTLOOK FOR 15Z WEDNESDAY THROUGH SATURDAY...
Wednesday: VFR. W wind gusts 15-20 kt.
Thursday: Mainly VFR. W wind gusts 15-20 kt during the day.
Friday...IFR with snow likely, mainly during the day. Chances for
snow lower at night. NE-N wind gusts 20 kt in the afternoon and
at night.
Saturday...Mainly VFR. NW wind 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...
Winds increase on the ocean today, then all areas tngt as low
pres tracks over then away from the waters. A SCA is in effect
thru tngt on the ocean, and only tngt on the rest of the
waters. The advy may needed to be extended thru Wed, especially
on the ocean.
Gales possible on the ocean and eastern nearshore waters Wed
night into Thu. Winds lower Thursday with sub SCA conditions
returning to non ocean waters early in the day, and on the ocean
by Thu night.
SCA conditions redevelop late Friday or Friday night, and may
persist on all waters through the weekend under NW flow. Gales on
the ocean will be possible once again Sat night into Sunday.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the forecast period.
&&
.TIDES/COASTAL FLOODING...
Localized minor coastal flood impacts likely for the afternoon
high tide along NJ harbor and tidally affected rivers, southern
bays of Nassau and Queens, and along Western LI Sound with
onshore flow around an area of low pressure tracking SE of the
area and only 1 1/2 ft of surge needed for minor flooding.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Winter Weather Advisory until 7 PM EST this evening for
CTZ005>012.
NY...Winter Weather Advisory until 7 PM EST this evening for
NYZ067>075-078-080-176>179.
Winter Weather Advisory until 1 PM EST this afternoon for
NYZ079.
NJ...Winter Weather Advisory until 7 PM EST this evening for NJZ002-
004-006-103>108.
MARINE...Small Craft Advisory from 6 PM this evening to 6 AM EST
Wednesday for ANZ331-332-335-338-340-345.
Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353-
355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/BR
NEAR TERM...JMC/JM
SHORT TERM...JMC/JM
LONG TERM...BR
AVIATION...MW
MARINE...JMC/BR
HYDROLOGY...JMC/BR
TIDES/COASTAL FLOODING...