000
FXUS61 KOKX 070530
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
130 AM EDT Sat Oct 7 2023
.SYNOPSIS...
A cold front approaches tonight as the remnant low of Philippe
moves north, well east of the Delmarva coast. The cold front will
move across the area Saturday into Saturday evening as the
remnant low of Philippe reaches to off the New England coast and
then near the Maine coast 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 /THROUGH TODAY/...
Flood Watch in effect from late tonight through Saturday evening
for northeastern New Jersey, the lower Hudson Valley, New York
City, and Fairfield and Nassau counties.
The forecast is mostly on track so far. A longwave upper trough
will be approaching tonight, and then moves into the northeast
and mid Atlantic Saturday as the trough begins to interact with
the remnant of Philippe. At the surface a cold front approaches
tonight and moves through Saturday into Saturday evening, as the
remnant low tracks well to the east. The frontal system will
interact with tropical moisture from the remnant low late
tonight into Saturday, and with increased lift, a weak low level
jet, and precipitable water values around 1.5 inches, and warm
cloud processes, periods of moderate to heavy rainfall will be
possible. Hi res models have come into better agreement with the
potential of a narrow band of heavy rainfall, and increased
rainfall amounts. With higher confidence of this occurring has
issued a Flood Watch as urban and poor drainage areas could see
flash flooding. Also small and fast responding streams across
northeastern New Jersey could flood as antecedent conditions
remain wet from recent rainfall.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
The upper trough closes off and becomes negative Saturday
evening as the remnant low merges with the frontal system.
Precipitation will end Saturday night as the cold front tracks
east and north of the area. Colder air moves in with
temperatures returning to seasonal to slightly below for
Saturday night.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Low pres will retrograde into wrn Quebec on Sun, dropping into
the 970s by 00Z Mon. Despite the distance from the center of the
sys, it will be breezy across the area due to the depth of the
low. Deep mixing will allow for temps to reach around 60,
despite h85 temps falling to around 1C. Steep lapse rates during
the day, so have added isold sprinkles to the fcst. Bkn flat cu
around 3000 ft possible as well.
Less wind on Mon as the low over Canada weakens and another sys
approaches from the west. Flow aloft backs to the sw, but sfc temps
remain blw normal with less mixing across the interior. Dry wx
expected with lapse rates not as steep.
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 /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
A cold front approaches from the west, passing through during
the afternoon and evening.
IFR and lower likely with showers becoming likely, especially
after 09z. 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 most likely late morning and early
afternoon for NYC terminals on NW, but IFR or lower 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.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely due to changing flight categories.
Locally heavy rain possible early morning through early
afternoon. An isolated thunderstorm possible.
Timing of cold front passage/NW wind shift may be off by 1-2
hours.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Saturday night: VFR. NW-W gusts around 20 kt.
Sunday: VFR. W winds 15-20kt G25-30kt.
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 tonight through at least
Saturday night as increasing swell from the remnant low of
Philippe move into the ocean waters. Behind a cold front
Saturday night northwest winds and gusts will be increasing,
with gusts reaching SCA levels across all the forecast waters
Saturday evening, and a SCA has been issued.
West winds will produce sca conditions on all waters Sun. Winds
will decrease Sun ngt, but seas on the ocean will remain aoa 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 has
increased, however, there is uncertainty as to where this may
occur.
A basin wide average of 1.5 to 2.0 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,
tonight through Saturday evening, and 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 will set 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
Saturday 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 tonight into Saturday and to 6 to 9 ft
Saturday night, and , 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...
-- Changed Discussion --
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.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/MET
NEAR TERM...JC/MET
SHORT TERM...MET
LONG TERM...JMC
AVIATION...JC/DS
MARINE...JMC/MET
HYDROLOGY...JMC/MET
TIDES/COASTAL FLOODING...