000
FXUS61 KOKX 060912 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
412 AM EST Wed Dec 6 2023
.SYNOPSIS...
A low strengthens well offshore today with an upper level
disturbance moving across the local area. Tonight, the low moves
well out into the Atlantic with weak high pressure moving in.
This high pressure area quickly weakens though and gives way to
a weakening low pressure area approaching Thursday. A warm
front will lift north of the region Friday into Saturday with
surface high pressure in control. A strong frontal system
approaches from the west Sunday with its associated cold front
moving across overnight Sunday. High pressure returns for early
next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Cloudy conditions along with the potential for some rain and
snow showers will be seen today. The primary forcing for this
will come from mid level height falls as a trough moves across
the area. Mid level positive vorticity advection will be taking
place, enhancing lift. POPs are taken from a consensus of the
mesoscale models and their associated reflectivity fields.
Meanwhile, a low strengthens and models convey a deepening of
10-14 mb during the day as it passes well southeast of the area.
This will steepen the pressure gradient and make for breezy NW
winds for today. The trough aloft and these winds will make for a
colder than normal day, as forecast highs only reach the upper 30s
to lower 40s. Taking the winds into account, the wind chills this
afternoon are forecast to be mainly around 30 to 35 degrees.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
For tonight, the low moves well out into the Atlantic with high
pressure moving in from the west. This high pressure area will
be relatively weak with its core staying well south and west of
the area.
The high pressure area will quickly weaken though and give way
to an approaching wave of low pressure on Thursday. This wave of
low pressure will also weaken. Rain and snow showers are
possible once again but POPs are less, just slight chance, with
less vertical forcing.
Temperatures tonight for lows are forecast to range from the
lower 20s to near 30. Forecast highs on Thursday are in the
upper 30s to lower 40s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Thursday night into Saturday will have weather driven primarily by a
ridge building in from the west with surface high pressure to our
south. Warm air advection at 850mb is expected, with Friday`s 850mb
temps at 3-4C while Saturday warms to 8-10C which is 7-9C above
average. Warm surface temperatures will also be aided by a southerly
flow returning late Friday into Saturday with the passage of a warm
front. Followed the NBM for temperatures during this timeframe as it
captured the warming trend well. High temperatures for coastal areas
in the upper-40s to near 50 on Friday warming into the low/mid-50s
on Saturday while high temperatures for interior areas are in the
mid-40s on Friday warming into the low-50s on Saturday. No precip is
expected Thursday night through Saturday. This will bring highs
about 5-10 degrees above average on Saturday.
On Saturday a Colorado low develops. Where? That`s the million
dollar question. The latest guidance have quite diverging solutions.
The 00Z ECMWF, 00Z GFS and 00Z GDPS all have one or more surface
lows developing in different locations. The GFS has a low developing
in the Central Great Plains moving into Canada via the Great Lakes
on Sunday. The GDPS has the same thing, except the low fast tracks
into the Great Lakes late Saturday with a stronger low developing
over the Lower Mississippi Valley before tracking through our CWA
overnight Sunday into Monday morning. The ECMWF has three different
areas on low pressure simultaneously as the front approaches us late
Sunday into early Monday before deciding on growing a stronger low
into New England. The ICON and UKMET both agree with the GFS
solution, so I am leaning towards that solution for precip types
which would have the event remaining primarily a rain event with
temperatures cooling enough for snow only after the precip has
exited. All global guidance do agree on several factors, however.
That all show a strong trough that inverts right before passing
through late Sunday into Monday and a strong pressure gradient with
and preceding a cold front.
The inverted trough would signal a more potent system, so moderate
to heavy rain may occur at times as the line of rain moves through
late Sunday into early Monday. NBM deterministic and LREF mean both
show about 1-1.5" of rain. NBM Probabilities greater than 2" are
less than 10% everywhere except northwestern zones around 20-30%
chance. The though is a quick shot of moderate or heavy rain, but
not lasting long enough to create any significant concerns for
flooding. As of now, WPC has us under a Marginal Risk for excessive
rainfall.
The cold front is currently expected to pass through overnight
Sunday into Monday. Ahead of the front a strong LLJ develops with
925mb winds around 60-80 knots. This will translate to southerly
winds at the surface increasing preceding the front Sunday
afternoon and reaching their peak late Sunday night just before the
front with wind gusts around 40-45 mph currently forecasted. After
the front winds take a turn from the west with some lower gusts
sticking around before diminishing Monday night.
Zonal flow takes over on Tuesday along with surface high
pressure. Temperatures will be near normal.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Low strengthens well offshore with upper level disturbance passing
overhead today. Tonight, low moves farther away with weak high
pressure briefly moving in.
Mainly VFR during the TAF period. Some MVFR possible with rain and
snow shower activity today. Winds will become more N-NW and
increase to 10-15 kt. Gusts near 20 kt develop this afternoon into
this evening. Precipitation ends by this evening. Gusts diminish
late tonight.
...NY Metro(KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for brief rain or snow with possible MVFR.
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
Late Tonight: VFR. 20 kt gusts ending.
Thursday-Saturday: VFR.
Sunday: Mainly VFR in the morning with afternoon SE-S gusts
20-30kt. Rain/MVFR/IFR/LLWS mainly in the afternoon and night
with SW gusts 35-40kt at night. Chance for occasional gusts up to
45 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA remains as is for ocean this afternoon into tonight. Sub-SCA
conditions otherwise for the short term for non-ocean waters and
for Thursday for all waters.
Sub-SCA conditions are expected Thursday through Saturday night with
ocean seas averaging close to 3 ft. Winds and seas should ramp up
quickly during Sunday with small craft conditions quickly going to
Gales in all likelihood by later in the day. Solid gales are
expected across all waters Sunday night, with gales likely lingering
into Monday morning.
&&
.HYDROLOGY...
No hydrologic issues expected through Saturday night.
1.0-1.5" of rain is possible Sunday night into Monday morning. At
this time only minor and localized hydrologic impacts appear
possible, though confidence remains low this far out.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 1 PM this afternoon to 4 AM EST
Thursday for ANZ350-353-355.
&&
$$
SYNOPSIS...JM/BR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BR
AVIATION...JM
MARINE...JM/BR
HYDROLOGY...JM/BR