000
FXUS61 KOKX 071221
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
721 AM EST Sun Jan 7 2024
.SYNOPSIS...
Low pressure will pass east of the region today. High pressure
moves across the area on Monday. Low pressure strengthens and
passes west of the region Tuesday into Wednesday. The low will
then move northeast and weaken Wednesday into Thursday. Weak
high pressure then returns thereafter through Friday. Another
low pressure system may impact the area on Saturday.
&&
.NEAR TERM /THROUGH TONIGHT/...
The fcst is on track. The main area of pcpn has exited the area
to the N and E. Left behind is some light mixed pcpn or rain,
with some pockets of steadier pcpn beginning to develop. The
main question for today is how this pcpn develops/evolves on
the back side of the sfc low with the approaching upr trof.
All of the modeling supports areas of pcpn today, with the radar
now supporting that idea. However, with mrgnl bl temps, it will
be difficult to accumulate snowfall except in the coldest
portions of the interior unless there are solid mdt to hvy
rates. Time heights show a lack of deep lift, so confidence in
getting these rates is low. That said, the CAMs do show some
bands developing, particularly in the late mrng and aftn, so
have kept some light accums in the fcst. Generally expecting an
inch or less, but around 2 inches with locally higher amounts
possible if the bands do develop.
Based on this thinking, an advy has been issued for the interior
to account for the additional snow today, as well as the patchy
fzdz this mrng. Elsewhere, any bands of snow, should they
develop, will be handled with an SPS. All warnings have been
canceled.
Went close to the 4km NAM Nest for temps today. Winds will be
strongest this mrng, before diminishing as they back to the NW
thru the day.
Dry tngt as the sys exits. Clearing skies and NW winds can be
expected with strengthening subsidence. The NBM with local
adjustments has been used for temps.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Fair weather on Mon as high pres builds towards the area. The
high ridges over the cwa Mon ngt, allowing for light winds but
cold temps. The NBM may be too mild in this scenario and my need
to be undercut in future fcsts.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
*Key Points*
* A significant storm system will impact the region Tuesday into
Wednesday.
* A period of heavy rain, and river and coastal flooding are
increasingly likely with this system. See hydrology section below.
* Strong winds with the potential for 45 to 60 mph gusts, highest
along the coast, Tuesday night into early Wednesday are also
possible.
There were no major changes to the forecast. Deterministic and
ensemble guidance continues to be in agreement of the overall
evolution of this system. An upper level low and associated surface
low will lift out of the Southern Plains early Tuesday and track
west of the area as the surface low strengthens. The low will pull
moisture up from the Gulf and track over the Great Lakes (model
PWATs around 1.25" would be close to or just over the max PWAT
value for the 01/10 OKX sounding per SPC`s Sounding Climatology
Page). An all rain event is likely given this track, with the
exception of snow or a rain/snow mix at the onset for portions of
the Lower Hudson Valley. Given the moisture fetch, enhanced forcing
from an upper jet and frontal approach, the ingredients are in place
for a period of heavy rainfall. The NBM probabilities of 3 inches
over 24 hours are now widespread 60 to 80 percent, with 90 percent
across portions of northeast NJ and the Lower Hudson Valley. See the
hydrology section below.
The other hazard with this system will be the winds. Latest guidance
still shows 65-70 kts at 950mb, with only a weak inversion in place.
The thinking remains that the area could see widespread 30 to 40 mph
winds with gusts 45 to 60 mph, with the higher end of these values
across the coast. The latest NBM max wind gust probabilities of
seeing 60 mph are as high as 60 percent along the Long Island south
coast.
Weak high pressure looks to build in Friday. There is potential for
another low pressure system to impact the area on Saturday.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Low pressure departs farther east of the region today into tonight.
Residual low level moisture and intermittent precipitation will keep
IFR conditions through this morning. The precipitation will be more
rain for coastal terminals and more snow for inland terminals.
Coverage of precipitation decreases this afternoon into early this
evening but will trend towards more snow showers concerning the type
of precipitation. Conditions are expected to improve to MVFR
this afternoon. However, snow showers could temporarily cause
for brief IFR to redevelop. For tonight, mainly dry and VFR
conditions are expected.
Winds will become more NE and will remain gusty going into this
morning. Sustained winds near 15 to 17 kts with gusts near 20 to 25
kts are forecast.
Gusts by mid to late morning are forecast to diminish with winds
becoming more northerly in direction. Sustained winds will decrease
to near 10 to 12 kt.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of end of IFR and MVFR could vary a few hours compared to
TAF. Gusts end time may be off by a few hours compared to TAF.
There could be fluctuation between categories, especially this
afternoon.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday: VFR.
Tuesday: VFR early becoming MVFR or lower. Rain during the afternoon
and becoming heavy at night. E-ESE winds 15-20kt with gusts
25-30kt in the afternoon. SE winds increasing Tuesday night to
25-35kt, gusting 40-50kt, highest winds along the coast. LLWS
likely at night.
Wednesday: MVFR or lower with rain in the morning. Rain ending late
in the day with conditions improving. S-SW wind 20-25kt gusting 35-
45kt. Gusts decrease afternoon into the night.
Thursday: VFR. WSW winds 10-15kt with gusts near 20 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
As low pres pulls away today, winds will decrease from W to E. A
SCA has been issued for the wrn waters today. A gale warning
remains in effect for the ern waters until noon. Seas on the
ocean will remain at SCA lvls thru Mon, then fall blw Mon ngt.
Elsewhere, winds and seas blw advy criteria Sun ngt thru Mon
ngt.
Strong low pressure will track west and impact the area Tuesday
through Wednesday. Gale force winds look likely on all waters, as
well as the potential for storm force gusts for a period Tuesday
night into early Wednesday. In addition, waves on the ocean waters
likely reach 15 to 20 ft. Continued mention of gales and storm
force gusts in the HWO.
&&
.HYDROLOGY...
No hydrologic impacts are expected through Monday.
Thereafter, significant hydrologic impacts are likely. A period
of heavy rainfall Tuesday night into Wednesday will likely
result in flooding across the region. Any total runoff would be
enhanced inland with melted snowfall, especially across the
interior. The Weather Prediction Center Excessive Rainfall Outlook
remains largely unchanged. There is a moderate risk from northeast
NJ up through the Lower Hudson Valley and he rest of the forecast
region is in a slight risk. River levels across northeastern NJ and
the Lower Hudson Valley, where the heaviest rainfall is expected to
fall, are expected to rise. Currently, a widespread 2 to 3 inches is
forecast, with 3 to 3.5 possible across northeastern NJ into
portions of the Lower Hudson Valley.
&&
.TIDES/COASTAL FLOODING...
E/NE gusty winds into this morning will produce a surge of about 2
to 3 ft, resulting in widespread minor coastal flooding during the
morning high tide cycle today for all coastlines but more localized
minor for Manhattan coastline. Localized moderate is a possibility
across the south shore back bays of Nassau and southwest Suffolk
counties. Isolated dune erosion expected during this morning high
tide, overwashes not expected.
The potential for a significant coastal flood event with the Wed AM
high tide remains. Potential for SE gale to storm force winds
Tuesday Night into early Wednesday, bringing potential for
widespread moderate to locally major coastal flooding. Early
guidance from Steven`s NYHOPS ensemble is producing surge values of
3 to 4 ft. This will also coincide with increasing astronomical
tides with a new moon on Jan 11. Along the oceanfront, potential for
15-20 ft surf causing widespread dune erosion and scattered
overwashes. Localized dune inundation/breaches possible where dunes
have been compromised by earlier storm events. More details on this
event early next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Winter Weather Advisory until 5 PM EST this afternoon for
CTZ005>008.
Coastal Flood Advisory until 10 AM EST this morning for
CTZ009>012.
NY...Winter Weather Advisory until 5 PM EST this afternoon for
NYZ067>070.
Coastal Flood Advisory until 10 AM EST this morning for NYZ071-
073-078-080-176-177-179.
Coastal Flood Advisory until 11 AM EST this morning for NYZ079-
081.
NJ...Winter Weather Advisory until 5 PM EST this afternoon for
NJZ002-004-103.
MARINE...Gale Warning until noon EST today for ANZ331-332-340-345-350-
353.
Small Craft Advisory until 4 PM EST this afternoon for ANZ335-
338-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/JT
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JT
AVIATION...JM
MARINE...JT
HYDROLOGY...JMC/JT
TIDES/COASTAL FLOODING...