118
FXUS61 KOKX 081744
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1244 PM EST Sun Dec 8 2024
.SYNOPSIS...
Weak high pressure ridge approaches today and shifts offshore
tonight. A weak low pressure center along a warm front moves
through during Monday afternoon and evening, with the warm front
remaining nearby through Tuesday. The region will then be in the
in warm sector Tuesday night into Wednesday with an approaching
cold front to the west. This cold front moves across Wednesday
night. High pressure then returns, building in from the west
Thursday into the next weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast remains on track with some adjustments to temperature,
dew point, and sky cover to reflect the current conditions.
Drying over the area continues as a weak clipper system moves
north and east of the area today.
Weak ridging occurs over the region through the near term
period as we`ll be between low pressure shifting east through
New England and another storm system off to the west. The ridge
should be strong enough to hold off any precip attempting to
reach us by the end of tonight. Breezy to start the day, then
the winds diminish this afternoon into tonight. Temperatures
will be above normal today with highs in the upper 40s to lower
50s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
A warm front approaches from the SW through the day Monday in
association with a broad area of low pressure stretching from the
upper MS Valley to the Ohio Valley and Mid-Atlantic. A weak area of
low pressure center develops along this warm front and passes
through the forecast area this evening. Moisture out ahead of
the warm front heads our way with rain chances starting late in
the morning, but not becoming likely in most spots until Monday
afternoon. The rain continues into Monday evening with the weak
low center passing through. The rain should be primarily on the
light to moderate side with a total of quarter to half inch of
accumulation. Temperatures remain above normal on Monday in
spite of the rain and clouds with highs ranging from the mid 40s
inland to around 50 for coastal areas. Rainfall lingering
during the evening hours to the north and east of the city ends
by midnight with the weak low shifting ENE. The warm front
however remains over part of the forecast area, but will be in a
weakened state - still can`t rule out a slight chance of light
rain or drizzle overnight. Winds will be light with low dewpoint
depressions, so patchy/areas of fog is anticipated.
The warm front or trough remains over or nearby through the day
Tuesday. Low level moisture remains locked in below 5-6kft with dry
conditions aloft. Weak lower level omega may be enough to produce
light rain or drizzle in spots at any time during the day, but most
of the day should be rain-free. Cloudy, with highs 50-55 in most
areas.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Strengthening upper level trough, baroclinic zone, and surface low
pressure approaching with its associated cold front are the weather
features for the local region Tuesday night through Wednesday night.
For the upper levels, strong upper level low moves from South
Central Canada into the Great Lakes Tuesday night through
Wednesday night. This is part of a deep upper level trough that
will be developing with phasing and tapping into the Gulf of
Mexico as it digs southward Tuesday night and then as it moves
east it will access the Western Atlantic waters for Wednesday.
The associated strong vort max moves across the local region
Wednesday night. Strong shortwave departs well north of the
region Thursday, but an upper level trough remains across the
region Thursday into Friday. The atmosphere transitions to a
less amplified pattern with the trough exiting and weakening for
next weekend.
At the surface, the region will be getting into the warm sector
as a warm front will be north of the region. An associated cold
front approaches the region but with low pressure forecast to
develop and strengthen along it, this cold front will not move
across until Wednesday night. Low level warm and moist air
advection increase Tuesday night into Wednesday. See hydrology
section for extra details as precipitable waters are forecast to
reach well above typical levels for this time of year. Low
pressure more rapidly intensifies for Wednesday night into early
Thursday morning, with models indicating around a 15 to 20 mb
drop in 12 hours, traveling from near the region to New England
vicinity to Quebec. This strong low is then expected to move
farther north, farther away from the local region. Meanwhile,
high pressure will begin to build in from the west. This high
pressure area will have origins in Alberta, Saskatchewan and the
Dakotas with a very cold airmass moving in. This high builds in
Thursday into the first half of next weekend.
This is setting up a widespread moderate to locally heavy rain
event, especially for eastern sections of the region. This is where
models have their combination of generally where the low level jet
will be and highest precipitable waters. Upper levels have a
focus of the forecast region being in the right rear quadrant of
a SW to NE jet streak for Wednesday into Wednesday night,
conveying strong synoptic lift. Coastal areas could even have
an embedded thunderstorm for Wednesday. This could result in
some strong winds being brought down to the surface, perhaps
some wind gusts briefly of near 40 to 50 mph. The eastern areas
seen having a higher chance of getting the heavy rain and gusty
winds appears to be Southern CT and Long Island. However,
subsequent model runs will have to be monitored for any shifts
westward with low pressure, low level jet and heavy rain axis.
Strong cold air advection follows Wednesday night as the low travels
northeast and deepens more rapidly. Would expect ongoing rain to
become more showers and intermittent in period. However, with wet
bulb cooling as drier air tries to work into the region, along with
strong cold air advection, precipitation ends as snow showers
Wednesday night into early Thursday morning.
Temperatures generally above normal Tuesday night and Wednesday and
then near normal Wednesday night. Below normal temperatures for
Thursday through Friday night before airmass moderates going into
next weekend.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
Low pressure moves along the New England and Canadian border this
afternoon, and then moves northeast into the Canadian Maritimes
tonight into Monday morning. A warm front approaches Monday
afternoon.
VFR through much of Monday morning. A chance of rain with MVFR,
arriving towards or just after midday. Flight categories begin
to fall around 18z for city terminals, with IFR approaching
the Monday evening push.
W winds this afternoon with gusts mainly 20 to 25 kt with a few
peak gusts for the next couple of hours for eastern most terminals
up to 30 kt. Winds eventually subside tonight to less
than 10 kt as the wind direction becomes more variable. These light
and variable winds continue into early Monday before more of a SE
flow develops near 7 to 10 kts for the late morning.
NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Amendments possible to adjust timing of ending of gusts towards
early this evening.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday: MVFR to IFR, at times, in rain, particularly in the
afternoon and evening.
Tuesday: MVFR or lower during the day. Increasing chance of rain
late Tue into Tue night. IFR or lower possible at night. Rain will
become more steady at night and increase in intensity.
Southerly wind gusts 15-20 kt developing late at night.
Tuesday night: Steady rain develops Tuesday night with sub
VFR becoming IFR.
Wednesday: IFR likely, possibly sub-IFR at times. Rain may become
heavy at times. S to SW gusts 20-35 kt during day. Possible
thunder and LLWS. W-NW gusts 20-30 kt at night. Potentially
higher gusts possible Wednesday into Wednesday night. VFR returns
late Wednesday night.
Thursday: Mainly VFR with gusty W winds G25-30kt.
Friday: VFR, NW winds.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
SCA continues on the non-ocean waters through early this evening.
On the ocean, the advisory goes through midnight tonight,
except east of Moriches Inlet where it is in effect until 6 am
with lingering elevated seas. An occasional gale force gust
can`t be ruled out this afternoon, but advisory conditions
should prevail. Sub-advisory conditions for Monday, and this
could be the case through Tuesday. Waves may however reach 5 ft
on the ocean Monday night into early Tuesday with the help of a
weak low pressure center shifting through.
Tuesday night, SCA conditions forecast on ocean, developing mainly
late. Otherwise, sub-SCA for the rest of the waters Tuesday night.
Gales possible on eastern non-ocean waters and ocean waters
Wednesday into Wednesday night. Otherwise, SCA conditions forecast
for all waters Wednesday through Thursday. SCA conditions remain
likely on the ocean for Thursday night but for non-ocean waters, sub-
SCA conditions are forecast.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic issues expected through Tuesday. Heavy rain
possible at times Tuesday night through Wednesday with the
potential for flooding in low lying and poor drainage areas.
Steady rain, heavy at times, persists Wednesday night across
Southern CT and Long Island. Would expect mostly minor flooding
but there is a marginal to slight chance for flash flooding,
which would be more localized. Extra uncertainty here on
rainfall amounts and where heavy rain axis sets up. Model
potential for PWATs of near 1.3 to 1.5 inches Wednesday, which
would be above the 90th percentile and around to above the max
for OKX sounding climatology for December 11th. GFS integrated
vapor transport shows most increase along Eastern Seaboard
Wednesday into early Wednesday evening.
Total rainfall forecast from Tuesday night through Wednesday
night ranges from near 1.75 inches to near 2.75 inches, lowest
across NYC, interior NE NJ and the Lower Hudson Valley and
highest across SE CT and Eastern Long Island. There could be
locally higher amounts especially across Southern CT and Long
Island which have more favorable lift. As mentioned before,
there is uncertainty and these rainfall amounts could easily
have some changes in subsequent forecasts.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 6 AM EST Monday for ANZ350.
Small Craft Advisory until midnight EST tonight for ANZ353-355.
&&
$$
SYNOPSIS...JC/JM
NEAR TERM...JC/MW
SHORT TERM...JC
LONG TERM...JM
AVIATION...JE
MARINE...JC/JM
HYDROLOGY...JC/JM