000
FXUS61 KOKX 071146
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
746 AM EDT Sat Oct 7 2023
.SYNOPSIS...
A cold front will move across the area this afternoon and into
this evening as the remnant low of Philippe moves northward,
well to the east of the area by Sunday morning. Low pressure
remains north of the area into the beginning of next week, with
frontal systems impacting the area around the middle and end of
the week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A Flood Watch in effect through this evening for northeastern
New Jersey, the Lower Hudson Valley, New York City, and
Fairfield and Nassau counties.
Forecast remains generally on track. Updated temperatures, dew
points, and winds to reflect observations. Some scattered
showers are continuing to develop near the NYC metro but the
heaviest of which are well to the south and not making much
progress in the direction of NYC. Expecting a more robust
development of showers as the prefrontal trough begins to
interact with the inverted trough over the Mid-Atlantic coast
over the next several hours.
A longwave upper trough approaches the area today and brings
through a cold front by the afternoon. Ahead of the cold front,
southeasterly flow advects moisture onshore from the far
northwestern remnants of Philippe allowing for the development
of an inverted trough just off the Mid-Atlantic coast. This
should support the gradual development of showers and possible
thunderstorms through the morning. As of now, this shower development
has been a relatively slow process and has thus far been much
more underwhelming than CAMs have been suggesting in the
previous 24 hours. Recent runs of hires CAMs have backed off on
the training of heavy showers and thunderstorms in the vicinity
of the NYC metro area until the prefrontal trough approaches
the area sometime after 8AM. Regardless, the Flood Watch will
remain as the antecedent conditions in the previous few weeks
have allowed soil to remain fairly saturated.
The general consensus is that scattered showers continue to
develop this morning with light to locally and briefly moderate
intensity. As the prefrontal trough approaches later this
morning, a more organized convergence zone allows the
development of heavier showers with embedded thunderstorms to
move through the area, though these seem to be fairly
progressive as the cold front quickly approaches from the west.
There may be a period of 1-2 hours with moderate to locally
heavy rainfall that may result in localized instances of flash
flooding, especially in the Flood Watch area. Rainfall rates are
expected to maximize in the 1 to possibly 2 inch per hour range.
The cold front then pushes the heavier rainfall eastward through
the day before exiting the area at some point during the first
half of tonight. Rainfall totals have been reduced a bit in the
vicinity of the NYC metro with max values at just under 2
inches. A widespread 1-1.5 inches is possible for the western
and northern portions of the CWA. Eastern portions of the CWA
may see a half inch or less.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
The upper trough pushes the front through the area tonight and
closes off and becomes negatively tilted this evening as the
remnant low of Philippe merges with the frontal system.
Colder air moves in with temperatures returning to seasonal to
slightly below for tonight. Lows will be in the 40s for much of
the area.
Fairly dry conditions are then expected Sunday through Monday as
the area remains in the base of a large trough and the
associated cut-off low positioned well to the north. This will
allow for breezy NW winds continuing through the timeframe with
gusts upwards of 25-30 mph on Sunday and gradually diminishing
into Monday. Highs Sunday and Monday will be in the upper 50s to
low 60s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A weak front comes thru late Tue into Wed with a few shwrs possible.
Little change in airmass expected with temps remaining a little blw
normal. Not much moisture to work with so any pcpn should be mainly
light.
Humidity increases Thu and Fri ahead of a strong cold front. Chances
for rainfall increase thru the period, although the heaviest pcpn
may hold off until Fri ngt or later. Temps warming back to around
normal with smaller diurnal swings.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
A cold front will pass through the terminals this afternoon and
evening. Low pressure will then meander over New England and
southeast Canada into early next week.
IFR with some areas of LIFR as showers continue to develop from
the NYC metro on north and west. Showers will continue into the
afternoon, but likely focus over Long Island and Southern
Connecticut late afternoon and evening. An isolated thunderstorm
is possible, but confidence not high enough to include in TAFs.
Improvement to MVFR is expected late morning into the early
afternoon for NYC terminals on NW, but IFR may continue into
the evening further east. VFR returns late afternoon into the
evening from west to east.
E-ESE winds 5-10kt will shift to the NW behind the passage of a cold
front this afternoon. Gusts 20-25 kt should become frequent behind
the front and continue into the evening. Winds and gusts may
weaken a bit late tonight into early Sunday morning before
increasing after day break.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely due to changing flight categories.
Timing of improvement to VFR may be off by 1-3 hours.
Timing of cold front passage/NW wind shift may be off by 1-2
hours.
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sunday: VFR. W winds 15-20G25kt.
Monday: Mainly VFR. Chance of showers at night. SW G15-20kt
Tuesday...Manly VFR. Chance of showers. S-SW G15-20kt.
Wednesday...VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A SCA remains on the ocean waters through at least Sunday night
as increasing swell from the remnant low of Philippe move into
the ocean waters. Behind a cold front tonight northwest winds
and gusts will be increasing, with gusts reaching SCA levels
across all the forecast waters by this evening.
West winds will produce SCA conditions on all waters Sun. Winds
will decrease Sun night, but seas on the ocean will remain at
or above 5 ft. Seas on the ocean are progged to be in the 3-5 ft
range Mon-Tue, then less on Wed. Seas then build again on Thu
ahead of a strong frontal sys. Otherwise, winds are progged to
remain blw SCA lvls Mon-Thu attm.
&&
.HYDROLOGY...
The potential for a narrow band of heavy rainfall remains this
morning, though confidence in its occurrence has decreased.
A basin wide average of 1 to 1.5 inches, with locally as much
as 2 to 3 inches, of rainfall is expected across much of
northeastern New Jersey into the Lower Hudson, New York City,
Nassau County New York, and Fairfield County Connecticut,
through this evening. A Flood Watch has been posted for these
areas with the potential for isolated to scattered flash
flooding. There is uncertainty as to where a band of heavier
rainfall sets up, with the possibility of being from
northeastern New Jersey into Nassau and Fairfield counties. In
locations outside of the Flood Watch 0.5 to around 1.0 inches of
rainfall will be possible tonight through this evening.
No hydrologic impacts expected Sun-Fri.
&&
.TIDES/COASTAL FLOODING...
Long period SE swells from the remnant low of Phillipe will
build to 5 to 7 ft today and to 6 to 9 ft tonight, presenting
the likelihood of additional beach erosion/escarpment from an
east to west sweep of 5 to 7 ft breaking surf. Because water
levels are not astronomically high, the dune erosion threat
during times of high tide is isolated. Swells subside Sunday
into Sunday night.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch through this evening for CTZ005-009.
NY...Flood Watch through this evening for NYZ067>075-176>179.
NJ...Flood Watch through this evening for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory from 6 PM this evening to 8 PM EDT Sunday
for ANZ331-332-335-338-340-345.
Small Craft Advisory until 8 PM EDT Sunday for ANZ350-353-355.
&&
$$
SYNOPSIS...JMC/MW
NEAR TERM...MW
SHORT TERM...MW
LONG TERM...JMC
AVIATION...DS
MARINE...JMC/MW
HYDROLOGY...JMC/MW
TIDES/COASTAL FLOODING...