983
FXUS61 KOKX 200148
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
848 PM EST Tue Nov 19 2024
.SYNOPSIS...
High pressure will remain in control through Wednesday. Low
pressure will then strengthen south of Long Island from
Wednesday night into Thursday, and linger nearby through Friday.
The low will exit across New England and Atlantic Canada this
weekend, followed by weak high pressure Sunday into Monday.
A frontal system may approach on Tuesday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
High pressure ridge axis aloft shifts in from the west tonight
with not much change in the surface pressure. This will make it
difficult for showers reaching the ground in association with
moisture along a weak shortwave moving along the ridge axis.
Enough guidance shows light rain amounts in the vicinity of NYC,
so added chance of sprinkles for the metro area later this
evening. NBM was used for low temperatures.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
The ridge axis will remain overhead to start on Wednesday, but
should slowly begin moving east in the afternoon and evening.
The daytime hours will remain dry as the main frontal system
will still be located well to our west. Clouds will likely be
thickest across the western half of the area for much of the day
with some high level clouds across the eastern half. This will
yield mostly cloudy conditions west and partly cloudy conditions
east. Highs will reach mostly 55-60.
A deep, closed upper low will spin across the Great Lakes region
Wednesday night. Jet energy rounding the base of the low will
help develop a new surface low along the Middle Atlantic coast.
The low will then quickly deepen into Thursday over the region
as it shifts generally north. Widespread rain will develop and
move across the area from west to east Wednesday night. The rain
quickly becomes moderate to locally heavy at times, especially
after midnight, and possibly still at this intensity during the
morning commute - mainly over LI and southern CT. The rain
should then continue through Thursday afternoon, but become
light to occasionally moderate.
The strengthening low will bring gusty winds, especially near
the coast. Gusts up to around 30 mph will be possible Wednesday
night into Thursday. If the low were to remain just south of
Long Island longer, winds could be a bit higher.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
-- Changed Discussion --
Colder air will move in Thursday night as the sfc low occludes
and moves up into SW New England and the lower Hudson Valley,
and the upper low moves overhead. This will introduce potential
for wet snow across the Lower Hudson Valley and far interior NE
NJ Thu night into Fri AM, especially in the higher elevations.
The timing and location of this process will ultimately
determine the extent of the colder air and where the most
organized forcing sets up. Global models in particular show
potential for heavy banded precip Thu night via combo of H5 QG
forcing/cold pool aloft with the upper low moving across, and H7
frontogenesis/trowal on the back side of the occluding sfc low
as it moves inland, with associated low level CAA and dynamic
cooling changing precip to heavy wet snow somewhere inland
north/west of NYC. Pinpointing the exact location of mesoscale
features like this is a challenge 48+ hours out, and will be
scrutinized more closely via trends in later guidance in
collaboration with WPC and neighboring WFO`s.
The strengthening low will bring gusty W-NW winds Thu night,
especially near the NYC metro area and across Long Island, with
gusts 30-35 mph possible.
The upper low should continue to spin over the area Fri into Fri
night, with rain still likely throughout Fri afternoon, tapering off
to sct snow/rain showers inland and rain showers in the NYC metro
area and along the coast.
There is still the slight chance of some rain/snow showers well
inland on Sat due to cyclonic low level flow and any lake effect
streamers that can make it down into the area.
The cold pool aloft will be deep over the area, so any warming temps
at the sfc should hit convective resulting in extensive low
cloudiness Fri into Sat, aside from any areas of forcing from both
the sfc and aloft.
The fcst goes dry Sunday into Monday with the low pulling up into
Atlantic Canada. A low approaching from the W could then bring
chance PoP with its leading warm front on Tue.-- End Changed Discussion --
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
High pressure remains in control into Wednesday afternoon, then
moves off the coast late day into Wednesday night.
VFR through TAF period with winds generally light and variable
into Wednesday afternoon, then becoming easterly less than 10kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
No unscheduled amendments expected.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday Night...VFR becoming MVFR/IFR with rain developing
and E-SE gusts up to 35kt.
Thursday...MVFR/IFR with rain in the morning, then mostly MVFR in
the afternoon with a chance of rain. Gusts up to 35kt possible with
direction becoming W in the afternoon.
Friday...Mainly MVFR with periods of rain, rain/snow inland. Winds
15 to 25 kt.
Saturday...MVFR possibly becoming VFR late. NW winds gusting 20 to
25 kt.
Sunday...Mainly VFR. West winds gusting to 20-25kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
High pressure over the waters through Wednesday will lead to
winds and seas below SCA levels. Low pressure develops and
strengthens over the waters Wednesday night into Thursday. This
will lead to increasing winds and building seas. Wind gusts
25-30 kt are likely Wednesday night through Thursday night.
There is also potential of gale force gusts. Still not enough
confidence in Gales to go with a watch at this point, but will
continue to mention the potential in the HWO.
SCA conds likely on all waters Thu night as low pressure moves
to the north and winds shift W-NW. Gales may be possible on the
ocean waters once again. The low will be slow moving and will
continue producing SCA conditions From Fri into Sunday. There is
a chance for occasional gales, especially on the ern ocean
waters on Sunday.
&&
.FIRE WEATHER...
Light winds are expected Wednesday along with minimum RH values
46-60 percent. SPS will be issued shortly for S CT. A
substantial wetting rainfall is then expected Wednesday night
through Friday.
&&
.HYDROLOGY...
Storm total QPF calls for 1.5-2.5 inches from Wednesday night
through Friday, with most of this falling from late Wednesday
night through Thursday evening. No hydrologic impacts are
expected given the recent dry weather and progressive nature
of any heavier rainfall.
&&
.TIDES/COASTAL FLOODING...
Although levels may approach minor flooding thresholds with the
high tide cycle Wednesday morning along the south shore back
bays of Nassau County, do not think a statement will be
necessary at this point.
Minor coastal flooding will be more possible with the daytime high
tide cycle Thursday. The extent of any minor coastal flooding will
be dependent on the magnitude and duration of E flow as well as
fetch and surge.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JC/BG
NEAR TERM...JC/BG
SHORT TERM...JC
LONG TERM...BG
AVIATION...MET
MARINE...JC/BG
FIRE WEATHER...BG
HYDROLOGY...JC/BG
TIDES/COASTAL FLOODING...