000
FXUS61 KOKX 101846
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
146 PM EST Sun Dec 10 2023
.SYNOPSIS...
A strengthening frontal system approaches the region this
afternoon and moves across the area tonight into Monday morning
as low pressure deepening along it as it tracks into Canada.
Strong high pressure building to the south on Tuesday will
flatten out, allowing a cold front to approach Tuesday night and
pass through late Tuesday night or Wednesday morning. Another
strong high will then build from the west for later in the week,
then shift off the New England coast Saturday night.
&&
.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
** Confidence remains high for a significant frontal system to
impact the region through the near term period.
** Flood Watch remains in effect for the entire CWA.
** High Wind Advisories/Warnings in effect for much of the
Coast.
Forecast on track with no significant changes into the afternoon.
A strong cold front continues to approach the region this
afternoon and will pass over the region tonight into early
Monday morning. In addition, an area of low pressure is forecast
to develop along the front, passing through or nearby the
forecast area before rapidly deepening to our NE.
Have increased isolated thunder wording in terms of coverage with
this update as embedded convective elements have ticked up with
radar and even a lightning strike detected in Queens. A
secondary warm front is currently lifting through which has
aided in lift in the past couple of hours. Otherwise forecast
remains on track.
The entire forecast area will likely seeing rain by the end of
the afternoon. The rain is expected to become moderate to
locally heavy at times as early as the afternoon as per latest
CAM reflectivity. The best chances for the moderate to locally
heavy rain is expected tonight. The heavy rain potential comes
from a developing strong low level jet combining with deep
synoptic lift aloft and an anomalously moist air mass. Some
models continue to show some elevated instability, so with deep
lift, will keep in an isolated thunderstorm in the forecast.
Models continue to favor eastern areas for the higher total rain
amounts, as the llj will be stronger here, and
forcing/convergence near the deepening low center will be
passing through or nearby. Further enhancement may occur in
parts of CT due to speed convergence on a southerly flow. Latest
00z Hi-res guidance seems to be picking up on this potential,
with HREF values now forecasting the potential for as much as
5-7 inches possible across portions of SE CT. The flood watch
remains up for the entire CWA and has been extended to include
much of Monday morning and early afternoon. See the hydrology
section below for more details.
A high wind warning continues for Suffolk County. A wind
advisory is also continues for Brooklyn, Queens, and Nassau
County in NY, and remains in effect also for coastal sections
of New Haven, Middlesex and New London in CT.
For several days now, forecast guidance has been progging 925mb
winds reaching 60-80 kt east of NYC tonight. Even by late afternoon,
they`re progged at 50-60 kt. There will be a low level inversion,
but not particularly strong. Especially with the threat of
convectively enhanced downpours and models showing 50-60kt winds
below the inversion at 1000 ft, there is an increased threat of
seeing wind gusts reaching high wind warning thresholds in some
areas. For now, thinking the place with the best chance to meet high
wind warnings will be across Suffolk county. While portions of
NYC/Nassau County and part of the CT coast, could see an isolated
gusts to warning or come close to it, felt it was best to keep them
in a Wind Advisory. All the forecast guidance is indicating a
fairly sharp cut off with respect to the strongest winds occur. Can
nor rule out the day shift potentially having to adjust the
headlines a bit based on the newer forecast data that comes in
during the day. The combination of a saturated ground and strong
gusty winds, would expect some wind damage across the advisory and
warning locations.
The front moves east of the area between 12-15z Monday morning.
While some drier conditions are expected, rain chances don`t
completely come to an end as the flow aloft remains cyclonic and
we`ll be within the right entrance region of an upper jet streak.
Cold air wraps in behind the front, and may cause a mix of rain and
snow well NW of the city in the morning. Little to no snow
accumulation expected. Remaining breezy through the day as we dry
out for the afternoon. Highs generally in the 40s.-- End Changed Discussion --
&&
.SHORT TERM /MONDAY NIGHT/...
Mainly dry conditions expected Monday night as high pressure
continues to gradually build into the region. The gradient will
continue to gradually weaken, but remain tight enough for at least
some gusty conditions possible through the first half of the night.
Lows will fall into the middle and upper 20s to lower 30s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
No changes to the long term. Followed the NBM closely. The previous
discussion follows:
Quasi-zonal flow aloft in the wake of one departing trough on Tue
will give way to another northern stream trough on Wednesday, which
should drive a cold front through either late Tuesday night or
Wednesday morning. Confluent mid level flow after this trough
passage, followed by ridging aloft Fri-Sat, will then maintain
strong sfc high pressure over the area, with perhaps a weak
intervening cold frontal passage Friday night. A storm system to the
west should hold off until just after the forecast period, with some
increase in high/mid cloud cover Sat into Sat night.
Forecast follows the NBM for the most part given close enough NWP
model guidance agreement during this time frame, with only minor
adjustments. Fair wx should prevail through the period, with only
slight chance (20%) PoP for next Sunday. Near normal temps Tue- Wed,
and a little below normal Wed night-Thu after the cold frontal
passage, should moderate to a few degrees above normal Fri-Sat via
ridging sfc and aloft.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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** HIGH AVIATION IMPACTS EXPECTED THROUGH THE TAF PERIOD **
A strong cold front moves through tonight.
Mostly IFR through the night with rain, heavy at times, and iso
TSTM. Precipitation may mix with or briefly change over to
snow Monday morning at KSWF. Not enough confidence to include
in the TAF at this time.
Strengthening southerly flow this afternoon, more so from
approx KJFK/KLGA eastward. LLWS for all but KSWF this afternoon
through the cold front passage. 2kft winds increase more
significantly this aftn east of KJFK/KLGA with speeds 60kt+ at
KISP and KGON, and 45-55kt for the other terminals.
FROPA timing is 1-4Z for western and NYC terminals and 6-10Z
for eastern coastal terminals as the cold front slows down.
Behind the FROPA, wind shifts to the NW-WNW with gusts 25-35kt
lasting well into the day Monday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Isolated TSRA possible this afternoon and evening. Forecast
winds and gusts may be too strong by at least 5 kt into this
evening through this evening ahead of the cold front.
OUTLOOK FOR 18Z SUNDAY THROUGH FRIDAY...
Monday: VFR in afternoon. NW-WNW winds G25-35kt
Tuesday: VFR. SW gusts 15-20 kt in the afternoon.
Wednesday: VFR. W to NW gusts 15-20 kt in the afternoon.
Thursday and Friday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Gale and storm warnings on the area waters as a strong cold front
pushes across the area tonight.
Winds and seas should ramp up quickly today with SCA conditions
quickly going to gales by late in the day/early evening. Storm
warnings are in effect for the central and eastern ocean zones as
well as the south shore bays, Peconic and Garners Bays and the
eastern part of Long Island Sound. These locations have the best
chances to see wind gusts reach 50 kt, especially from about
midnight tonight through early Monday morning. The Storm warnings
are up until 11am, however its possible they will be able to be
dropped down to a Gale warning earlier. Gales are then expected on
all waters through the day Monday and possibly linger into Monday
evening. Ocean seas are likely build to 10-16 feet during this time
with waves over 5 ft across portions of eastern Long Island
Sound.
Longer term, SCA cond expected for the most part. Hazardous ocean
seas 5-8 ft Tue AM should subside to 4-6 ft by afternoon, then
remain at those levels into at least Wed night. Meanwhile W flow
gusting up to 25 kt on all waters Tue night, should shift NW by Wed
morning after a cold frontal passage. Gusts could peak at 30 kt on
the ocean Wed night. Lingering 25 kt gusts are possible on the ocean
and the open Sound waters into daytime Thu.
&&
.HYDROLOGY...
-- Changed Discussion --
A flood watch remains in effect for the entire area. Across portions
of Long Island and Southern Connecticut, 3 to 5 inches of rainfall
is likely, with locally 6+ amounts possible. Elsewhere, 2-4 inches
is likely. Most of this rain will fall in a 12 hour period. WPC
has placed our central and eastern CT zones in a moderate risk
of excessive rainfall through tonight.
As a result, widespread urban and poor drainage flooding is likely,
with some areas of more significant flooding possible, including the
flooding of some rivers and streams. Heavier downpours will be
possible as early afternoon, but impacts are more likely later
afternoon into the night. WPC has much of the forecast area in a
Slight Risk in their excessive rainfall outlook for today and
tonight.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
A strong cold front will bring increasing S flow late today
into tonight. The system brings potential for minor coastal
flooding with the Monday morning high tide cycle. Winds quickly
shift to the W-NW late tonight/early Monday morning, which will
help keep water levels down during times of high tide. That
said, latest Stevens NYHOPS 95th percentile numbers and taking
into account wave runup on south facing coastlines suggest some
potential for the CT coastline and the forks of Long Island to
touch minor thresholds.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Flood Watch through Monday afternoon for CTZ005>012.
Wind Advisory from 6 PM this evening to 11 AM EST Monday for
CTZ010>012.
NY...Flood Watch through Monday afternoon for NYZ067>075-078>081-
176>179.
Wind Advisory until 6 AM EST Monday for NYZ075-176>179.
High Wind Warning until 11 AM EST Monday for NYZ078>081.
NJ...Flood Watch through Monday afternoon for NJZ002-004-006-
103>108.
MARINE...Gale Warning until 6 PM EST Monday for ANZ331-335-338-355.
Storm Warning until 11 AM EST Monday for ANZ332-340-345-350-
353.-- End Changed Discussion --
&&
$$
SYNOPSIS...BC/MW
NEAR TERM...BC/JE
SHORT TERM...BC
LONG TERM...MW
AVIATION...JC
MARINE...BC/MW
HYDROLOGY...BC/MW
TIDES/COASTAL FLOODING...