discussion on 2023-12-18

000
FXUS61 KOKX 181151
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
651 AM EST Mon Dec 18 2023

.SYNOPSIS...
Strong low pressure passes through the area today. The low then
tracks north into southeastern Canada tonight with high pressure
slowly building in during Tuesday. High pressure will then remain in
control through the upcoming weekend.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
No major changes to the forecast with this update.

Low level jet near 2000 feet has peaked at around 85kt on KOKX
radar in the past couple of hours, and as of 6AM is still at
around 75kt. There have been reports of downed trees and gusts
58+mph in some of the warned area so far. No changes have been
made to the High Wind Warning or Wind Advisory with this update.
With surface temperatures near 60, rapid pressure falls helping
downward momentum transfer, and occasional heavy downpours
(some potentially with thunder), still a chance that areas under
the high wind warning continue to see gusts around 60 mph. The
threat for advisory and warning- level winds may very well end
by mid-morning in most spots, but will leave the end time of the
wind headlines at noon for the time being as convection in
association with a strengthening low pressure center to our
south passes over or nearby the coastal areas after the
strongest winds aloft have already shifted east. Gusts otherwise
will be in the range of 25-40mph this afternoon.

Flood Watch remains posted for most of the area. Additional
rivers are expected to see at least minor flooding later this
morning, especially over NE NJ and the Lower Hudson Valley where
the rain has been the heaviest so far, and with upsloping on a
SE wind, will see the most rainfall for the entire event. See
the hydrology section for more details.

Mild with high temperatures in the upper 50s to lower 60s, and
a chance that some records are broken. See the climate section
below for more details.

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
The low will be north of the area tonight with a brief break in
precipitation. Wrap around moisture in the back side of the storm
with the approach of a closed mid-level will bring a chance of
rain/snow showers well NW of the city late tonight into Tuesday
morning. There may even be slight coating of snow in the higher
terrain of Western Orange County. Dry for Tuesday night with the
flow aloft becoming anticyclonic and surface high pressure building
in.

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Upper level low over the eastern Great Lakes region will weaken
into a trough as it moves toward the forecast area. A weak area
of low pressure looks to form along the frontal boundary
offshore, and a blocking pattern will then set up as the trough
becomes an upper level low once again and will interact with the
weak surface low offshore, becoming vertically stacked by the
middle of the week. With a blocked pattern over the region, the
surface high that builds in during Tuesday night will remain over
the area through next weekend. This will sustain a period of dry
weather Wednesday through Sunday.

The area will be on the eastern side of the high during much of the
week, with a northwest to northerly flow for much time. This will
lead to seasonable temperatures with highs in the 40s.

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --HIGH IMPACT AVIATION EVENT TODAY...

Strong low pressure approaches tracks near the region this
morning and then lifts to the north and east, dragging a cold
front through this afternoon.

Widespread IFR/LIFR conditions this morning with improvement behind
the departing surface low and cold front in the afternoon.
Conditions are forecast to improve to MVFR in the afternoon,
becoming VFR by late afternoon for all but KGON, which should
follow by early evening. Cigs on Tuesday may occasionally go
MVFR.

Peak S/SE winds occurring now thru mid morning or so, 20-30kt
G30-50kt, with strongest along the coast. Slow improvement late
morning through the afternoon, with winds veering to S/SW, then
W/NW around 20kt G30-35kt in the afternoon into early evening.
Winds will then gradually diminish and back to the SW G20-25kt
Monday evening. Gusts 20 to 25 kt linger through Tuesday.

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

Isolated 45 to 50 kt gusts thru 15Z this morning, especially at
KJFK and KLGA.

Gusts after 13Z could be more occasional than frequent until low
passes to the east in the early afternoon.

Timing of flight categories could vary by 1-2 hours.

OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...

Tuesday: Mainly VFR, brief MVFR cigs possible. WNW G20-25kt in
the afternoon.

Wednesday through Friday: VFR.

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

.MARINE...
-- Changed Discussion --Storm Warning remains in effect through this morning on all waters.
Gales will then prevail this afternoon on the ocean and perhaps over
the eastern bays and eastern LI Sound. Otherwise, solid SCA
conditions this afternoon for the rest of the waters. Ocean seas are
expected to range roughly up to 16-21ft during the day today.

All waters will probably be experiencing SCA conds by midnight
tonight, then as winds continue to subside, conditions should be
below advisory thresholds by the end of tonight on the non-ocean
waters. Seas remain elevated on the ocean through at least the end
of the week as long period swells from an offshore storm keep waves
elevated.-- End Changed Discussion --

.HYDROLOGY...
Mostly 2 to 4 inches of rainfall with locally higher amounts
possible are expected by the end of today. Periods of heavy rain
should continue through mid-morning. The highest amounts are
expected in portions of northeastern New Jersey, into the Lower
Hudson Valley, and possibly into portions of Southwestern
Connecticut (Fairfield County). With flooding of fast responding
streams possibly reaching moderate flooding benchmarks, and flooding
of poor drainage and urban areas, and localized to scattered flash
flooding becoming more likely, the Flood Watch remains in effect
tonight through this afternoon. A few of the faster responding
streams of northeastern New Jersey may even reach major flooding
benchmarks. Residual river flooding will then continue tonight as
levels subside. Afterwards, no hydrologic impacts expected through
next weekend.

.TIDES/COASTAL FLOODING...
Coastal flood warnings continue for southern Queens, southern
and eastern portions of LI and coastal CT, and expanded for NE
NJ as widespread moderate coastal flooding is likely with the
daytime high tide cycle today. This includes the tidally affected
rivers, particularly Hudson and Hackensack rivers, where the surge
is favored to be forced upstream by the strong southerly flow. There
is potential for locally major flood thresholds to be reached for
southern Queens, SW LI and twin forks, if windshift occurs near or
after the time of high tide.

Elsewhere, minor to locally moderate coastal flood potential exists
for NE LI and northern portions of NYC.

Peak surge of 3 1/2 to 5 ft will likely be between high tidal cycles
this morning. A later timing of windshift closer to today`s early
afternoon time of high tide will aid potential for major flood
thresholds to be reached or exceeded for the most vulnerable
southern Queens, SW and E LI portions of the area. This will likely
not be evident until the time of high tide is approaching. Forecast
is a blend of 75th percentile of PETSS, Stevens, and deterministic
ESTOFS.

Heavy rainfall and/or runoff coinciding with this afternoon`s high
tides will exacerbate street and property flooding issues along the
coast and tidally affected rivers.

Along the ocean beachfront, potential exists for 12-16 ft breakers
today (8-12ft for NYC beachfront), which combined with elevated
water levels, will likely result in widespread dune erosion and
scattered overwashes.

.CLIMATE...
Record high temperatures for December 18th...
EWR...64/1937
BDR...61/1937
NYC...63/1964
LGA...63/2006
JFK...64/1984
ISP...59/1984

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch until 5 PM EST this afternoon for CTZ005>007-
009>011.
Wind Advisory until noon EST today for CTZ005>007.
High Wind Warning until noon EST today for CTZ008>012.
Coastal Flood Warning until 6 PM EST this evening for
CTZ009>012.
NY...Flood Watch until 5 PM EST this afternoon for NYZ067>075-176-
178.
Wind Advisory until noon EST today for NYZ070>074.
High Wind Warning until noon EST today for NYZ075-078>081-
176>179.
Coastal Flood Warning until 6 PM EST this evening for NYZ071-
079>081-178-179.
Coastal Flood Warning from 10 AM this morning to 4 PM EST this
afternoon for NYZ074-075.
Coastal Flood Advisory until 6 PM EST this evening for NYZ072-
073-078-176-177.
NJ...Flood Watch until 5 PM EST this afternoon for NJZ002-004-006-
103>108.
Wind Advisory until noon EST today for NJZ006-104-106-108.
Coastal Flood Warning from 10 AM this morning to 4 PM EST this
afternoon for NJZ006-104-106-108.
MARINE...Storm Warning until 1 PM EST this afternoon for ANZ331-332-335-
338-340-345-350-353-355.

SYNOPSIS...JC/JP
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JP
AVIATION...DR/DW
MARINE...JC/JP
HYDROLOGY...JC/JP
TIDES/COASTAL FLOODING...
CLIMATE...