000
FXUS61 KOKX 051455 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
1055 AM EDT Thu Oct 5 2023
.SYNOPSIS...
High pressure remains in place to our north and east through the
day, before departing farther east tonight into Friday. The high
will give way to an approaching frontal system that will drag a cold
front through the area Saturday into Saturday night. Low pressure
lingers over the Northeast into the middle of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Fog is quickly dissipating across the area with daytime heating
mixing down drier air into the low levels. There may be a few
spots of dense fog along interior river valleys and hill tops.
Otherwise, the upper level ridge axis has shifted east of the
area as well as surface high pressure. The orientation of the
high well to our north and east will continue the E-SE onshore
flow. Today will be the last day of above normal temperatures
before a long period of at or below normal temperatures. Highs
today will be in the 70s.
The aforementioned onshore flow will advect an increasingly
humid airmass into the area. Some patchy light rain or drizzle
is possible at the very end of the tonight period.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A digging upper level trough approaches from our west, becoming
negatively tilted before closing off. At the same time, TC Phillipe
approaches from the south and east. Phillipe will stay well to our
east, but aid in increasing the moisture over our area before
getting pulled back west into northern New England. A surface low
associated with the approaching upper level trough will pass well to
our north, but drag a cold front through our area Saturday into
Saturday night.
After a dry week, this set up will allow rain chances to increase
through the day on Friday, and become likely Friday night through
Saturday. Expecting the showers ahead of the cold front Friday
through Friday night to be mostly light. The ECMWF is currently an
outlier showing a higher band of QPF during this time frame and does
not seem to be supported given the expected moisture and
instability. Will have to continue to monitor this trend especially
as the CAMs start to come into play. For now, the WPC as outlined
the area in a marginal risk for Day 2. There is potential for
this to be upgraded to a slight risk as WPC mentions in their
Day 2 ERO based on today`s 12z CAM guidance. Moderate to heavy
showers are then expected with the passage of a cold front
Saturday into Saturday night. Have removed thunder given the
forecast soundings showing very little CAPE through the profile.
Thunder can not be completely ruled out but thinking it will be
extremely isolated. NBM probabilities for 1 inch of rain over
any 6 hour period have actually lowered to less than 10%.
However, probabilities for 1 inch of rain over the 24 hr period
ending 00z Sunday have increased significantly to 65-85% for
most.
Rain tapers off late Saturday night into Sunday morning. Cool
air filters in behind the cold front, with lows Sunday morning
in the 40s.
Refer to the National Hurricane Center, https:/www.nhc.noaa.gov for
official forecasts on Philippe.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
For much of the long term, the area is positioned at the base of a
large trough and associated cut off low pressure system positioned
well to the north centered over Southern Canada. Behind the cold
frontal passage and through much of the week, winds will be
generally out of W/SW. Wind speeds will be a bit breezy Sunday and
into early Monday as the pressure gradient remains fairly tight over
the area as the low pressure initially occludes closer to the area.
Wind speeds lower into Tuesday as the center of the low moves
northward.
Lower heights and a cooler airmass will be advected into the area
allowing temperatures each day in the extended period to be
generally 5 to 10 degrees below average. Highs through the beginning
of the week will only be in the low 60s, eventually rising into the
middle 60s by midweek.
In terms of sensible weather, conditions seems to be generally dry,
though pieces of energy rounding the base of the trough and the cut
off low may result in some showers at times through the week, though
confidence in the timing and placement of any more organized showers
remains low at this time.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
High pressure centered well east of the New England will
gradually retreat farther offshore through Friday, while a
frontal system approaches from the west.
The fog has burned off at the terminals with VFR conditions
expected through this afternoon. Low stratus and fog are
expected to develop once again after 00Z. This will result in
sub-VFR conditions, though the timing and intensity of any
stratus or fog tonight remains uncertain. Some scattered showers
or areas of drizzle also remain possible late tonight and into
Friday morning.
Winds will be light, less than 10 kt, in S to SE component
through the TAF period.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
There is uncertainty with the exact timing of flight category
changes with respect to fog and low stratus development this
evening and overnight.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: MVFR/IFR with a chance of rain showers.
Saturday: MVFR or lower in rain showers.
Sunday: VFR. W winds 15-20kt with gusts up to 25-30kt.
Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Some patchy dense fog along the interface of the south shore of
LI and along portions of coastal LI Sound is quickly eroding
early this morning. Otherwise, sub- SCA conditions are expected
through Friday under a weak pressure gradient.
Ocean seas build to 5 ft Friday night as swells increase from TC
Phillipe. By Saturday night, ocean seas are expected to be 9-10 ft.
Winds also increase with and behind a cold frontal passage late
Saturday. SCA criteria gusts are likely on all waters Saturday
night through Sunday night before subsiding.
Ocean seas remain elevated above SCA criteria into early next week
as long period swells from distant Tropical Storm Philippe move into
the waters.
Refer to the National Hurricane Center, https:/www.nhc.noaa.gov for
official forecasts on Philippe.
&&
.HYDROLOGY...
Chances of showers start Friday and become likely Friday night
through Saturday. Periods of moderate to heavy rain are
possible. The WPC has now outlined the western 2/3 of the area
in a marginal risk for Day 2 (Friday) and much of the area in a
marginal risk, with a slight risk for portions of western
Connecticut, for Day 3 (Saturday). Much of the area will likely
see an inch to an inch and a half of rainfall in total. The main
threat is minor nuisance flooding, but there is potential for
isolated flash flooding.
&&
.EQUIPMENT...
Data from the Peconic River at Riverhead NY tidal gauge appears
to have improved. Will monitor the gauge over the next few days
to make sure it is in line with other nearby gauges.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...JT/MW
NEAR TERM...JT/NV
SHORT TERM...JT
LONG TERM...MW
AVIATION...DW
MARINE...DW
HYDROLOGY...JT/MW
EQUIPMENT...