000
FXUS61 KOKX 161046
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
546 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 6 PM THIS EVENING/...
-- Changed Discussion --
The fcst is on track. It snowed all night, with around an inch
accumulating across the cwa per reports relayed in. The next
batch of snow continues to come in from the SW this mrng. Cold
cloud tops in IR and some banding features on radar suggest the
potential for accumulating rates at times. Otherwise, the snow
will be generally light and not add up much.
As 12Z passes, the modeling brings in a surge of warm air aloft
from SE to NW as weak low pres tracks about 60 mi SE of Montauk
this aftn. There is some spread just how far E the subfreezing
column remains, with the most uncertainty stretching roughly
from DXR swwd into NJ.
Leaned on the NAMNest for temps, which was supported by the
HRRR. Most areas stay aob 32 today, except for much of LI and
perhaps sern CT. Winds are only briefly out of the ENE in NYC
before becoming NW again, drawing in more cold air. As a result,
expect a longer duration of mixed pcpn and fzra for most of the
area, and have extended the advisories because of this.
Otherwise, expecting another 1-2 inches of snow before the
wintry mix settles in. Timing of mixing will determine which
areas get more snow and less ice, and which areas get less snow
and more ice. Even the N shore of LI is very close to staying
blw freezing for most of the day.
The pcpn changes back to light snow late this aftn and eve
before ending by 00Z. As cold air surges back in, refreezing of
some surfaces is possible. This is why the advy has been
maintained until 7pm. If the pcpn ends and areas dry out
sufficiently, the advy can be canceled early.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Cold with temps blw freezing thu Wed. 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.
&&
.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 /12Z 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 snow, potentially LIFR at times in moderate snow,
through the early morning hours. Improvement to VFR in the late
afternoon or early evening.
The snow changes to a wintry mix across central/eastern Long Island
during the morning by 12-14z and works its way north and west
towards the NYC metro terminals 13-16z. Potential for some freezing
rain within this wintry mix, but timing is still a bit uncertain.
Lower Hudson Valley terminals should remain predominately snow for
the duration of the event. Southern CT terminals may see a wintry
mix late morning and early afternoon. The precip tapers off in
the early 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...
Periods of moderate snow with 1/2SM visibility possible thru 12Z.
Uncertainty with timing of precip type changes after 12z with
amendments likely. Sleet and freezing rain are possible 14-18z.
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 06Z WEDNESDAY THROUGH SATURDAY...
Late tonight: VFR. NW wind gusts 15-20 kt.
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...
CT...Winter Weather Advisory until 7 PM EST this evening for
CTZ005>011.
Winter Weather Advisory until 10 AM EST this morning for
CTZ012.
NY...Winter Weather Advisory until 7 PM EST this evening for
NYZ067>075-176>178.
Winter Weather Advisory until 10 AM EST this morning for
NYZ078>081.
Winter Weather Advisory until 1 PM EST this afternoon for
NYZ179.
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.
&&
$$
SYNOPSIS...JMC/BR
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...BR
AVIATION...DR/DS
MARINE...JMC/BR
HYDROLOGY...JMC/BR
TIDES/COASTAL FLOODING...