638
FXUS61 KOKX 291615
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1115 AM EST Sun Dec 29 2024
.SYNOPSIS...
A warm front lifts north of the area today. A strong cold front
swings through Monday morning. Brief surface ridging builds in on
Tuesday followed by another low pressure system on Wednesday. Low
pressure remains over souther Quebec while high pressure builds
to the south through the end of the week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Visibilities have by and large improved across the area. There
remains some locales across more northern areas that have some
patchy fog and low cloud cover persisting. But even in these
locations it will improve going through the afternoon as a warm
front which washes out some but also lifts north. This should
push any showers further north along with it. This will be
driven by developing low pressure over the Ohio Valley which is
deepening and lifts into the Great Lakes this evening. This is
giving the push to lift the warm front further north. Also have
lower PoPs through the afternoon and at the start of this
evening. Temperatures should max out near 50 across northern
sections, with middle and upper 50s elsewhere. Some lower 60s
have shown up in the warm section across Central NJ and cannot
rule out a few 60s nudging north into the NYC metro and portions
of NE NJ later in the afternoon.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
The aforementioned surface low lifting towards the Great Lakes will
drag a cold front through the area tonight into Monday morning. An
impressive LLJ strengthens over the area ahead of the front and
peaks in intensity early Monday morning around 60 to 65 kt at 925mb.
However, an inversion is in place and surface wind gusts are
expected to max out at 30 to 35 mph across Long Island and the
coast. An isolated 40 mph gust can not be completely ruled out.
Just ahead of the cold frontal passage a period of moderate to heavy
rain showers is expected. High pressure offshore will aid in
funneling Gulf moisture over our area as the low lifts towards the
Great Lakes. This stream of moisture is characterized by pwats
around 1.25 inches. This is shown in both the NAM and GFS. The
max moving average for the OKX 12z 12/30 sounding is 1.26 inches
per the SPC Sounding Climatology Page. This moisture combined
with deep lift will bring moderate to heavy rain. Some CAMs are
showing the potential for isolated 0.75 inch per hour rainfall
rates, mainly across Long Island and eastern CT. See hydrology
section below.
The cold front exits the area by late morning and then dry conditions
are expected with clearing skies. Model soundings show a brief
period of some mixing behind the front. This could bring a period of
some 25 to 30 mph wind gusts Monday afternoon.
Brief ridging builds in aloft and at the surface Monday night into
Tuesday. By late Tuesday, another shortwave embedded in the broad
upper level trough over the US will be lifting towards the area
along with an associated surface low. Some rain may just be getting
into far western areas by Tuesday evening.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A shortwave digging into the Tennessee Valley and Southeast US will
allow for a developing low pressure system to move into the area by
Tuesday evening and into early Wednesday. There remain some
differences in the exact placement of the low pressure system as it
shifts generally overhead Tuesday night into early Wednesday.
Regardless, rain is expected to begin to overspread the region from
southwest to northeast early Tuesday evening. A widespread rainfall
is then expected during much of the overnight as the energy of the
low pressure shifts to a developing coastal low that pushes off the
New England coast into Wednesday.
The low continues to intensify as it occludes over southern Quebec
into Thursday and Friday. This will result in generally dry
conditions and breezy NW flow through the end of the week, though
some remnant rain or snow showers can`t entirely be ruled out in the
wake of the departing low on Thursday. Persistent strong NW flow
will result in strong CAA through the end of the week.
Thanks to persistent NW flow, temperatures will be on a downward
trend from Wednesday onward. Highs on Wednesday will be above normal
in the middle 40s to lower 50s. By Saturday, highs are expected
below normal, in the lower to middle 30s.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
A warm front lifts north of the area this afternoon. A cold
front then approaches from the west late tonight and moves
through around daybreak Monday.
Widespread LIFR/IFR conditions for most. Improvement is likely
this afternoon as the warm front pushes further north. Best
chance for improvement will be along the coast with a good
chance of becoming VFR. However, farther north and west of the
NYC terminals, improvement will be slower and may never even
make it to KSWF. This improvement should be temporary before
conditions worsen again tonight with an approaching cold front.
Conditions begin to improve around daybreak as the cold front
exits the forecast area.
Coastal wind speeds increase during the afternoon today where S
gusts over 20kt possible late. Wind shear becomes increasingly
likely, especially heading into tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Extent of improvement this afternoon will be dependent on how
far north of the terminals the warm front gets.
Amendments are likely through the period with the timing of category
changes and wind shifts.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Mon Morning: Becoming VFR with W to WSW winds G15-20kt.
Tuesday: Mainly VFR, likely MVFR late Tue/Tue Night in -RA.
Wednesday: MVFR or lower in -RA likely, improvement to VFR possible
by afternoon. W winds in the afternoon G20-25kt.
Thursday: Mainly VFR. W winds G25-30kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
Areas of localized 1 mile visibility are expected to dissipate
this afternoon as a warm front lifts north. A southerly wind
increases this afternoon as low pressure tracks west of the area
as it moves north. Small Craft Advisories are in effect as
early as late this afternoon for some waters. Winds peak late
tonight into early Monday morning around 20 to 25 kt southerly
sustained winds for most, with gusts 25 to 30 kt. Seas on the
ocean peak around 8 to 10 ft early Monday morning. The Small
Craft Advisory expires Monday afternoon for all waters except
the ocean and eastern Sound zone. While winds fall below
criteria Monday night, seas will remain elevated potentially
through Tuesday.
An extended period of SCA is possible on the ocean waters as waves
increase ahead of the next low pressure system that is poised to
move over the area Tuesday night into Wednesday. Ocean wave heights
build to 3 to 6 ft Tuesday night, and 4 to 9 ft by Wednesday night.
Waves slowly diminish Thursday into Thursday night, but generally
remain above 5 ft.
Behind the low, a strong W to NW wind with gusts of 25-30 kt develop
on the ocean waters by Wednesday morning, and then on all waters by
late Wednesday into Wednesday night resulting in SCA conditions into
Thursday. There is a low chance for gales on the ocean during this
timeframe, but mainly for Thursday.-- End Changed Discussion --
&&
.HYDROLOGY...
A cold front will bring moderate to heavy rain showers late tonight
into Monday morning. Total rainfall amounts are expected to be
around an inch for most. There is some potential for isolated
rainfall rates of up to 0.75 inches per hour, mainly across eastern
CT and Long Island. Flooding is not expected, but minor urban and
poor drainage flooding can not be completely ruled out.
Thereafter, no hydrologic impacts are expected into the
beginning of next weekend.
&&
.TIDES/COASTAL FLOODING...
There continues to be a widespread distribution in the NYHOPS /
Stevens TWL forecast, primarily for the western LI south shore bay
locations into the first half of next week. The cycles that are
garnering attention are the early Mon and Wed cycles driven by a new
moon phase into Monday.
For the Monday morning high tide cycle, peak surge looks to
arrive a few hours before high tide. Current thinking is potential
for isolated minor for western LI south shore bays and western
LI Sound. If surge peaks a bit later and observed winds are
higher than current forecast, widespread minor flooding in these
locations can not be ruled out. Confidence is too low at this
time to issue any hazards.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 10 PM this evening to noon EST
Monday for ANZ331-335-338-340-345.
Small Craft Advisory from 10 PM this evening to 6 PM EST
Monday for ANZ332.
Small Craft Advisory from 6 PM this evening to 6 PM EST Monday
for ANZ350-353.
Small Craft Advisory from 4 PM this afternoon to 6 PM EST
Monday for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JP/JT
NEAR TERM...JE
SHORT TERM...JT
LONG TERM...JP
AVIATION...IRD
MARINE...JP/JT
HYDROLOGY...JP/JT
TIDES/COASTAL FLOODING...