discussion on 2024-01-11

000
FXUS61 KOKX 120252
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
952 PM EST Thu Jan 11 2024

.SYNOPSIS...
An area of low pressure dissipates across western New York
tonight, while high pressure builds in from the west. Another
strong low pressure system low will track to our west and impact
the area Friday night into Saturday. The low will send a cold
front through the area early Saturday, followed by a secondary
cold front on Sunday. High pressure briefly builds in for the end
of the weekend into early next week. A coastal low looks to
potentially impact the area sometime early to mid next week. High
pressure briefly builds in thereafter.

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --Removed any remaining PoPs this evening across the Lower Hudson
Valley, dry conditions expected everywhere this evening with just
some lingering cloud cover as a weak area of low pressure across
Upstate NY dissipated this evening. Skies gradually clear
overnight as high pressure builds in from the west. W/SW winds
will gradually diminish and become NW by morning.

Lows will be in the upper 20s/lower 30s for all but the NYC
metro, where it will be a few degrees warmer.-- End Changed Discussion --

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
Another strong, negatively tilted upper trough will lift
northeast across the mid Mississippi Valley on Friday and up
into the Great Lakes Friday night, preceded by deepening low
pressure. A strong frontal system out ahead of the low will be
preceded by deep-layered lift and anomalously high PWATs
(1.15-1.30").

Friday will be mainly dry as high pressure passes to the east.
NW winds in the morning turn around to the SE by afternoon. Rain
will advance across the area from SW to NE during the late
evening, overspreading the entire area by around or shortly
after midnight. This will be a progressive system with the
heaviest rain clearing far eastern LI and SE CT by around 8 AM.
This system will bring less rainfall to the area than it`s
predecessor, a widespread 1 to 2 inches, with locally higher
amounts possible. However, due to the recent stretch of rainfall
events, starting back in mid December, streamflows are running
high, and grounds are saturated. FFG values are extremely low
across NE NJ (under an inch), and while higher elsewhere, it
will not take long for faster responding river and streams to
reach or exceed bankfull. In addition, a strong SE flow will
favor orographic enhancement. Thus, a Flood Watch has been
issued for Friday night for NE NJ, portions of the Lower Hudson
Valley (Rockland and Westchester), and all of southern CT.
Coastal flooding could also exacerbate flooding for tidal
rivers. Elsewhere, the threat will be for mainly minor nuisance
freshwater flooding (outside of coastal flooding - see sections
below), but basement flooding has also been a problem for the
area due to the saturated soils.

SE winds will steadily ramp up during the evening hours Friday
with the potential for winds reaching advisory levels across
coastal sections after midnight, especially Long Island. Expect
gusts up to 40 mph inland and 45 to 55 mph at the coast.

A few lingering showers are possible Saturday morning, otherwise
conditions dry out with clearing. Gusty west winds on the backside
of the storm system will get up to 35 mph. Cold advection will
also ensue following a cold frontal passage in the morning.

Temperatures Friday through Saturday will remain on the warm
side. In fact, temperatures ahead of the cold front Saturday
morning will get to around 50 at the coast. Thereafter,
readings may remain steady before falling off late in the day.

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As strong surface low pressure, and associated upper level low,
continue to move into eastern Canada Saturday night, the area
remains in a tight pressure gradient as high pressure starts to
build in. Windy conditions will continue, with 25 to 30 mph gusting
35 to 40 mph through Sunday, with a few isolated higher gusts
possible along the coast. Later on Sunday, a shortwave trough
rotating around the upper low will move over the area and help push
a cold front through. This will usher in the coldest airmass of the
season for the area. A few light snow showers will be possible with
the front. Extended slight chance a bit further into the Lower
Hudson Valley, but did not go farther east as confidence is still
low. This may trend up over the next several forecasts. High
pressure continues to build in from the west and the pressure
gradient looks to finally relax by early Monday.

High pressure will only briefly be in control as attention then
turns to a potential coastal low that looks to impact the area
sometime early to mid next week. Uncertainty remains with this
system, and model spread has actually increased with today`s 12z
guidance vs the 00z guidance. Although slight timing differences,
the GFS and Canadian are similar and closest to the coast with the
low. However, their ensembles are farther south and east. The latest
ECMWF is a big change from the previous run and shows a much weaker
low well offshore, leaving the area dry. This is the result of a
less amplified upper level trough and any energy out ahead of the
trough staying farther south off the southeast coast. Stuck
relatively close to NBM given the spread across guidance. PoPs are
capped at low end likely for the southern half of the area. Given
the cold air in place, taking a mean track between the ensembles and
deterministic guidance, excluding the ECMWF, precip type looks to be
snow across much of the area, with rain and/or snow across Long
Island. Did no want to jump on the ECMWF outlier yet, but this trend
will have to be monitored. At this time it is too early to talk
specific amounts. Behind this system, brief high pressure looks to
build in.

Temperatures will trend down From Sunday through the middle of next
week. Highs in the mid to upper 20s are forecast Wednesday.

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --Weak high pressure slides offshore tonight. An area of low pressure
approaches from the southwest Friday, impacting terminals Friday
night.

VFR through Friday afternoon. MVFR or lower conditions quickly
develop after 00Z Sat as rain moves in.

W winds under 10 kt through this evening, shifts WNW or NW
overnight into early Friday before becoming light and variable
for a period late Friday morning into early afternoon. Thereafter,
increasing SE flow, with 20+ kt gusts developing toward 00Z
Sat.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments likely Friday night for changing categories.

Timing of wind shift late Fri AM into early afternoon may be off
by an hour or two.

Isolated 40 kt gusts possible toward 06Z Sat.

OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...

Friday night: Becoming MVFR, then IFR or lower in rain. SE
winds 15-25kt G30-40kt. Winds and gusts highest along the coast.

Saturday: MVFR or lower early in rain, then VFR. S winds becoming W
20-30kt G30-35kt.

Sunday...VFR. W 15-25kt G30-35kt.

Monday...Mainly VFR. Low chance for light snow late with MVFR
to IFR.

Tuesday...MVFR or lower possible with a chance of rain/snow.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --

.MARINE...
Storm and Gale watches remain up for Friday night as another
strong low passes to the west, resulting in strong SE winds.
Behind the system, a westerly gale is likely on Saturday,
especially for the ocean waters.

Although the center of the low will be well to our north Saturday
night, windy conditions will continue across the waters. Gale
conditions are expected on all waters through at least Sunday and
lingering on the ocean waters through the first half of Sunday
night. Small craft conditions likely only last a few hours longer on
the non-ocean waters, but will continue on the ocean with 5 ft waves
through early Monday.

Quiet conditions then expected until a coastal low potentially
impacts the area sometime early to mid next week. At this time, at
least Small Craft Advisory criteria is expected.

.HYDROLOGY...
Some river flood warnings continue across portions of NE NJ and
southern CT. The Passaic River is still in moderate to major
and will crest later tonight, otherwise other locations are
receding from minor levels.

Hydrologic impacts are likely Friday night into Saturday. WPC
continues a slight risk of excessive rainfall, due to another
round of moderate to heavy rain. One to two inches of rainfall
is currently forecast, with locally higher amounts possible.
With rivers and streams running high from previous rainfall,
widespread minor to moderate river flooding looks likely along
the quick responding rivers and streams in Northeast NJ, the
Lower Hudson Valley and southern CT.

There are no hydrologic concerns Saturday night through Thursday at
this time. It is too early to talk specific amounts with the
potential coastal low sometime early to mid next week, but in areas
with recent hydrologic issues, precip type is expected to be mainly
in the form of snow at this time.

.TIDES/COASTAL FLOODING...
Widespread minor to moderate, with areas of major, coastal
flood potential continues to increase for the Saturday morning
high tide as SE gales build surge to 3-4 ft Fri night, with a
wind shift to SW gales Saturday morning near the time of high
tide.

Timing of wind shift will be an important factor for the magnitude
of surge. This scenario, like the Tue night and Dec 18th
events, is conducive to water piling up in the Great South Bay
of LI during strongest wind forcing, inhibited from drainage
thru inlets as tide comes in and accompanied by high wave
action, and then shifting this elevated water to the east side
of the bay with the wind shift. Potential for widespread major
exits here. Major flood thresholds looks to be a reasonable
worst case for Jamaica Bay. Elsewhere, widespread minor to
locally moderate flooding is expected Sat AM.

Along the oceanfront, breaking surf height should be lower than
the last couple of events, but 12-16 ft breaking surf with
similarly elevated water levels, impacting compromised dune
structure will likely result in another round of widespread dune
erosion and scattered overwashes. Localized breaches possible
where dunes have been severely compromised and barrier beaches
are narrow.

Forecast details will be refined over the next 36 hrs.

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch from Friday evening through Saturday morning for
CTZ005>012.
Coastal Flood Advisory from 9 AM to 3 PM EST Saturday for
CTZ009-010.
Coastal Flood Warning from 7 AM to 2 PM EST Saturday for
CTZ011-012.
NY...Flood Watch from Friday evening through Saturday morning for
NYZ069>071.
Coastal Flood Advisory from 9 AM to 3 PM EST Saturday for
NYZ071-073-078-176-177.
Coastal Flood Warning from 7 AM to 2 PM EST Saturday for
NYZ178.
Coastal Flood Advisory from 7 AM to 2 PM EST Saturday for
NYZ072-074-075.
Coastal Flood Warning from 7 AM to 6 PM EST Saturday for
NYZ079>081-179.
NJ...Flood Watch from Friday evening through Saturday morning for
NJZ002-004-006-103>108.
Coastal Flood Advisory from 7 AM to 2 PM EST Saturday for
NJZ006-104-106-108.
MARINE...Gale Watch from Friday evening through Saturday afternoon for
ANZ331-332-335-338-340-345.
Small Craft Advisory until 10 AM EST Friday for ANZ350-353.
Storm Watch from Friday evening through late Friday night for
ANZ350-353-355.
Small Craft Advisory until 6 AM EST Friday for ANZ355.

SYNOPSIS...JT/DW
NEAR TERM...DR/JT/DW
SHORT TERM...DW
LONG TERM...JT
AVIATION...DR
MARINE...JT/DW
HYDROLOGY...JT/DW
TIDES/COASTAL FLOODING...