813
FXUS61 KOKX 092351
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
651 PM EST Mon Dec 9 2024
.SYNOPSIS...
A warm front will remain nearby through Tuesday and then lift
north of the area Tuesday night. An intensifying low pressure and
its associated strong cold front will impact the area Wednesday
into Wednesday night. A secondary cold front pushes through
Thursday morning followed by high pressure building across for
late in the week. A secondary cold front pushes through Thursday
morning followed by high pressure building across for late in
the week. A weakening disturbance moves across late in the
weekend followed by weak high pressure Monday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
The progressive middle level shortwave is now clearing the
region. Weak low pressure associated with the shortwave passes
to the east-northeast. However, the associated warm front will
become nearly stationary over the region through tonight.
The rain is shutting off as relatively drier conditions are
expected overnight with ridging building overhead. There is
potential for fog overnight. Cannot completely rule out some
locally dense fog given the saturated low levels, wet ground,
and weak winds. There will likely be low overcast through the
night which may help prevent anything dense. Lows will range
from the upper 30s inland to the lower and middle 40s elsewhere.
The warm front lingers nearby on Tuesday. There may be some pockets
of light rain at times in the morning and early afternoon, but
probabilities remain relatively low. There is a higher likelihood
for low clouds and some fog to persist through the day.
Steadier rain may begin developing towards evening west of the
NYC metro as the impactful low pressure/frontal system begin
organizing from the Ohio Valley down into the Appalachians.
Temperatures may stay in the 40s inland but could get into the
low 50s near the coast as the flow starts turning around to the
SE in the afternoon.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Active weather expected with wind and heavy rain Wednesday into
Wednesday Evening.
*Key Points*
* High Wind Watch across Eastern Suffolk County and southern New
London County Wednesday afternoon and evening. Potential for
southerly gusts up to 60 mph.
* Wind Advisory will likely be needed for additional counties/zone
across southern Connecticut and Long Island with potential for
southerly gusts 45 to 55 mph Wednesday afternoon and evening.
* Widespread rain expected Tuesday night, becoming moderate to
locally heavy Wednesday into Wednesday evening. Forecast amounts
range from 2 to 3 inches with locally higher amounts possible. A
few thunderstorms possible Wednesday evening.
* Unseasonably warm temperatures Wednesday quickly drop 25 to
30 degrees behind the systems cold front by day break Thursday
morning.
A deep upper level trough across the central states will amplify
Tuesday night and become negatively tilted Wednesday as it
approaches the east coast. A potent vortmax at the base of the
trough will lift north towards the area. The system will send a
strong cold front towards the area on Wednesday. The strong
cold front and associated vortmax/upper trough axis will lift
across the area Wednesday night leaving behind a broad upper low
over the Great Lakes.
Low pressure will develop over the Ohio Valley Tuesday night then
into the northeast Wednesday, likely across the Middle Atlantic
up into Upstate New York. The low will be broad initially, but
will intensify Wednesday evening as the aforementioned vortmax
races north around the base of the upper trough. The low should
then lift northward into southeastern Canada Wednesday night
allowing the cold front to move offshore.
The system will contain a deep feed of subtropical moisture,
especially on Wednesday and Wednesday evening. Widespread rain
will occur Tuesday night, but not anticipating anything heavy
during this time frame. As the low strengthens Wednesday, the
rain will become moderate to locally heavy at times. There are
hints on the 3kmNAM, HiresFV3, and even the GFS, ECMWF, and CMC
for a narrow convective line to move across with the actual cold
front Wednesday evening. There is some weak elevated
instability, especially from NYC metro on north and east to
support mention of thunder Wednesday evening. Stratiform rain
will continue behind the main line and behind the cold front for
a few hours before drier air brings an end to the precipitation
from west to east late Wednesday evening and towards midnight.
WPC has continued to place the eastern half of the area (east of
the Hudson and NYC) in a slight risk for excessive rainfall and
the rest of the area in a marginal risk. The main threat
appears to be minor urban and poor drainage flooding with a
localized flash flood threat.
The area should also be well into the warm sector with the
parent low to our northwest in the afternoon. An intense low
level jet will develop south of Long Island in the afternoon
and rapidly push northeast towards coastal New England in the
evening. BUFKIT soundings indicate an impressive 85-95 kt jet at
850 mb over eastern Long Island and southeast Connecticut.
These winds are above an inversion, but are a good indication of
the wind field helping transport lift and the subtropical
moisture. However, winds are still quite impressive closer to
the surface. 950 mb winds are shown to be 60-70 kt on both the
NAM and GFS, especially eastern Long Island and southeast
Connecticut.
There is always a question of how much of these winds mix down,
but given the warm boundary layer and SSTs still in the lower
to middle 50s, there is a decent potential for high winds.
Confidence is highest across eastern Suffolk and coastal New
London for a High Wind Watch Wednesday afternoon and early
evening. Southerly wind gusts have the potential to reach 60
mph. The watch may need to be expanded a bit further westward
and potentially inland across southeast Connecticut if the low
level jet trends a bit stronger or further west. Have held off
on a Wind Advisory for now, but one will likely be needed across
the rest of Suffolk and Nassau and south central Connecticut,
where southerly wind gusts could reach 45 to 55 mph.
Winds shift to the west with the cold front passage and should
decrease in magnitude quickly. However, there will still be
gusty winds Wednesday night with cold advection. Gusts should
average 25 to 30 mph much of the night.
Temperatures on Wednesday should rise into the lower 60s before
dropping into the 40s behind the front and then into the lower
and 30s by day break Thursday.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Points:
* Windy on Thursday
* Colder Thursday through Friday night
* Turning milder into the weekend with light precip, mainly rain
Saturday night into Sunday
The upper level trough axis pivots through and moves N of the
area on Thursday. This results in strong CAA, especially
further north across the area. Look for a windy day with a few
gusts potentially getting to about 40 mph, especially across
northern portions of the area on Thursday. The winds start to
subside later Thursday night with light winds on Friday as high
pressure quickly settles over the area. For wind chills Friday
morning expect widespread teens to around 20 that will make for
a cold wake up.
Temperatures then moderate into the weekend as an upper level
feature approaches from the west. The model consensus are
suggestive that the system weakens and the mid and upper level
disturbance de- amplifies as it makes its way into the area for
the second half of the weekend. This should bring mainly some
light precip mainly in the liquid form, but at the onset,
particularly across the northern portions it may begin as a
little snow or mixed precip. Kept PoPs at chance as there is a
lot of uncertainty with this system. The deterministic ICON /
German model actually spins up a potent southern stream system
and brings appreciable liquid amounts in the form of primarily
rain as it really conserves vorticity with the system. The newer
ECMWF also appears to wrap up the system, but in a slightly
different manner with more wintry precip on the front end for
northern sections. These solutions are more recent and may be
outliers, so will play it middle of the road for now. Behind
this system look for weak high pressure and upper level ridging
to work in quickly on Monday, albeit for a short time as another
fast moving system may affect the region towards Tuesday of
next week.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A weak low is now exiting NE while a warm front stalls nearby
into tonight and tomorrow. Another low arrives tomorrow night.
Many sites are briefly bumping back into MVFR status as the rain
exits, but are expected to quickly drop back to IFR and remain
so this evening into tonight. LIFR is also possible for many
terminals tonight. Most sites experiencing LIFR tonight, may
return to IFR tomorrow as fog clears up somewhat with ceilings
rising a few hundred feet. While IFR ceilings are likely, the
development of fog looks to also occur tonight. However,
confidence is low in fog developing for KISP, KBDR, and KGON.
Western terminals look more likely to experience fog. Rain
returns tomorrow evening under continuing IFR conditions.
Winds are currently veering to a W-SW direction as a low exits
NE. They are expected to become light and variable at most TAF
sites over the next several hours. Tomorrow afternoon winds
become E-SE 5-10 kts.
NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Amendments possible regarding ceiling and visibility changes
through tonight into tomorrow. Confidence is good in lower
ceilings near IFR/LIFR status. Confidence is lower on the
extent of IFR/LIFR fog and how long it will stick around into
tomorrow after developing tonight.
OUTLOOK FOR 00Z TUESDAY THROUGH SATURDAY...
Tuesday night: IFR and rain. SE-S gusts around 20kt with LLWS late.
Wednesday: IFR and rain, possibly heavy at times. Chance of thunder.
S-SW gusts increase through the day, potentially up to 40-45 kt
afternoon and evening with LLWS continuing. VFR returns late
Wednesday night with west winds gusting 30-35kt.
Thursday: VFR with W winds G30-35kt in the morning, then 25-30kt in
the afternoon.
Friday and Saturday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
Areas of fog may develop over portions of the waters tonight.
Conditions will remain below SCA levels on the waters through
Tuesday. Low pressure and its associated cold front will impact
the waters Wednesday into Wednesday evening. Southerly winds
will increase with quickly building seas through the day. There
is potential for gales on all waters by Wednesday afternoon. A
strong low level jet will move at least the ocean east of Fire
Island Inlet, and the eastern LI Bays and eastern LI Sound. This
should bring even stronger winds, potentially up to storm
force. Have issued a Storm Watch for these zones from 1pm-10pm
Wednesday. The western Sound, Harbor, and ocean west of Fire
Island Inlet should remain in gales and have issued a Gale Watch
from 1pm Wednesday until 6am Thursday. Once the strong low
level jet passes, gales are likely to continue elsewhere into
early Thursday. Rough seas are expected with this system,
potentially up to 4-7 ft on the Sound and 12 to 18 ft on the
ocean late Wednesday into Wednesday night.
Gale conditions are likely on the ocean waters Thursday, and
potentially on the non-ocean waters as well as intensifying low
pressure pulls away to the north and a strong pressure gradient
in place. Winds should subside with small craft conditions
likely for a good portion of Thursday night as things settle
down quickly into early Friday morning. Sub small craft
conditions return on Friday and should last into Saturday with
high pressure settling over the waters.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic issues expected through Tuesday.
Widespread rain is expected Tuesday night, which will continue
through the first half of Wednesday night. The rain will be
moderate to locally heavy at times Wednesday into Wednesday
evening. Rainfall totals look to range from 2 to 3 inches with
locally higher amounts possible. The main threat from this
rainfall will be from minor urban and poor drainage flooding.
There is also a localized risk of flash flooding. Rivers and
streams should remain below flood stage, but are likely to see
rises, especially the quicker responding locations.
Towards late in the week and into the early next week no
hydrologic impacts are anticipated at this time.
&&
.TIDES/COASTAL FLOODING...
Tide levels are not astronomically high on Wednesday. While peak
storm surge is expected to occur Wednesday afternoon and early
evening, most locations should remain below minor flooding
benchmarks. Will have to watch trends in the Great South Bay as
water levels may remain elevated and could touch minor
benchmarks as a strong southerly flow switches to the west
preventing water from escaping the bay quickly. Only minor beach
flooding and minor erosion is anticipated with this event.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...High Wind Watch from Wednesday afternoon through Wednesday
evening for CTZ012.
NY...High Wind Watch from Wednesday afternoon through Wednesday
evening for NYZ079-081.
NJ...None.
MARINE...Storm Watch from Wednesday afternoon through Wednesday evening
for ANZ331-332-340-345-350-353.
Gale Watch from Wednesday afternoon through late Wednesday
night for ANZ335-338-355.
&&
$$
SYNOPSIS...JE/DS
NEAR TERM...JE/DS
SHORT TERM...DS
LONG TERM...JE
AVIATION...BR
MARINE...JE/DS
HYDROLOGY...JE/DS
TIDES/COASTAL FLOODING...