968
FXUS61 KOKX 162000
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
400 PM EDT Fri Aug 16 2024
.SYNOPSIS...
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Weak high pressure remains off the east coast through Saturday
afternoon as a weak low moves slowly through the Great Lakes.
The high weakens Saturday night as the low continues to slowly
approach. A warm front slowly lifts north across the region
Sunday into Sunday night. A cold front then follows Monday, with
a secondary frontal passage into Tuesday. High pressure then
builds through the end of the week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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An upper ridge remains from New England into the Mid Atlantic
into late tonight with the ridge axis moving to the east toward
sunrise Saturday. Meanwhile surface high pressure remains along
the coast as low pressure tracks slowly eastward. With the ridge
moving east a few light showers may develop across the western
sections of the region by morning as some weak upper energy
moves into the ridge. With many of the CAMs indicating the
possibility have included a slight chance. Any smoke aloft will
remain over the area through tonight. With light winds and high
humidity into tonight patchy fog will once again be possible
across southeastern Connecticut and eastern Long Island.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
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The upper ridge moves a little farther into the western North
Atlantic Saturday and remains nearly stationary into Saturday
night with heights falling across the area with the approach of
a shortwave moving into the Great Lakes and upper Midwest
regions. With pieces of energy rotating through the eastern
trough from time to time scattered showers will remain
possible, especially across much of the area by Saturday
evening. Have included low chance and slight chances into
Saturday night. During Saturday night CAPE will be increasing to
around 500 J/kg with some instability and have mentioned a
slight chance of thunder across western areas. Any smoke aloft
early Saturday will be shifting to the east and into the
Atlantic as the upper ridge moves east.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
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The main period of concern in the long term continues to be Sunday
and Monday with potential of locally heavy rainfall.
*Key Points*
*A warm front slowly moves north and east Sunday into Sunday night
followed by a cold front Monday into Monday night.
*Locally heavy rainfall in showers and potential thunderstorms is
possible Sunday afternoon into Sunday night, mainly from NYC metro
on west.
*Another round of showers and potential thunderstorms Monday
afternoon and evening could bring another round of locally heavy
rainfall.
*A secondary front may pass Tuesday into Tuesday night followed by
high pressure and a cooler/drier air mass mid to late week.
An approaching upper level trough, with a frontal system on the
leading edge, shifts into the Northeast early next week. The
associated warm front lifts through Sunday into Sunday night. The
cold front follows Monday into Monday with potential of a weak wave
potentially forming along the boundary as it moves through the
region.
The first round of concern with locally heavy rainfall comes Sunday
afternoon into Sunday evening with the warm front. Guidance has been
trending slower over the last few days with highest probabilities of
organized convection occurring west of the NYC metro in the
afternoon and evening. This is likely due to lingering subsidence
further east from high pressure off the New England coast. The warm
front then shifts north and east could present with a heavy rainfall
threat further east overnight, but limited instability and forward
speed of the system may preclude the duration of heavy rainfall.
This will be refined in future forecasts as the CAMs fully run
through Sunday night in the next 24 hours. PWATs look to approach 2
inches late Sunday west of the NYC metro, before slowly shifting
eastward Sunday night. WPC has largely maintained a slight risk for
excessive rainfall across NE NJ and the Lower Hudson Valley with a
marginal into the NYC metro, western Long Island and southwest
Connecticut. There is a mainly localized flash flooding risk north
and west of the NYC metro. Mainly minor nuisance flooding is
possible further east.
Another round of showers and possible thunderstorms are likely
Monday into Monday night. This will mainly be associated with the
cold front, but if a wave of low pressure is nearby, the rainfall
could be enhanced somewhere across the region. This is highly
uncertain, but there will remain a threat for locally heavy
rainfall, minor nuisance flooding, and an isolated flash flooding
occurrence.
Severe weather parameters continue to look marginal, so not
anticipating anything more than an isolated severe thunderstorm
occurrence through Sunday night. Monday is a bit more uncertain and
may depend on if there is additional heating and destabilization.
The timing of the frontal system moving offshore is still somewhat
uncertain as the ECMWF/EPS and to some level the CMC are slower to
move the system offshore on Tuesday. There may be a secondary
frontal passage with the upper trough hanging back, with potential
of another low pressure and at least scattered showers lingering on
Tuesday. Notably the latest GFS/GEFS and ICON are much faster with
the system with high pressure building in and the front offshore on
Tuesday. Have maintained a chance PoP Tuesday which is consistent
with the latest National Blend. Model guidance is good agreement for
troughing aloft to linger over the eastern seaboard Wednesday before
the axis of the trough pushing offshore into the end of the week as
heights start rising. High pressure will build in Wednesday into the
end of the week.
Muggy conditions Sunday into Monday should transition to a much less
humid air mass mid to late week. Temperatures will mainly be in the
70s to around 80 during the day with 50s and low 60s at night, below
normal for mid August.-- End Changed Discussion --
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Weak high pressure remains in control through tonight with a
warm front approaching on Saturday. Showers increase from west
to east in the afternoon and early evening with chances of tstms
increasing after 20-22z.
VFR forecast.
Light southerly winds remain through Saturday with speeds
remaining at or under 10 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of onset of precip may be off by an hour or two.
OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...
Saturday Night: MVFR or lower conditions possible in showers/tstms.
Sunday and Monday: MVFR or lower in SHRA/TSRA.
Tuesday: Mainly VFR. MVFR or lower possible in any SHRA/TSRA in the
afternoon....mainly eastern terminals.
Wednesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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The SCA has been extended into Sunday night on the ocean with
potential that it will need to be extended into Monday. Rough
seas and long period swells will continue from distant Ernesto
Sunday into Monday. Please refer to NHC for official forecasts
regarding Hurricane Ernesto. Swells and seas should diminish
Tuesday into Wednesday with seas below 5 ft sometime on Tuesday.
Otherwise, below SCA conditions are expected Sunday through the
middle of the week.-- End Changed Discussion --
&&
.HYDROLOGY...
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A tenth to around one-quarter inch of rainfall is possible
Saturday night across the Lower Hudson Valley, into Northeastern
New Jersey, and New York City., with little to no rainfall east
and north. Locally heavy rainfall is possible Sunday afternoon
into Sunday night, especially west of the NYC metro and Hudson
River. Locally heavy rainfall remains possible across much of
the area Monday into Monday night. Rainfall amounts range from
around a half inch east to 1-2 inches from NYC metro on NW
Sunday through Monday. Locally higher amounts are possible. Some
flash flooding is possible across the more flood prone areas of
NE NJ and adjacent areas of the Lower Hudson Valley, where a
slight risk for excessive rainfall exists. Elsewhere, a marginal
risk is in place with right now isolated flash flooding and
mainly minor nuisance flooding are possible.
No additional hydrological concerns follow Tuesday through late
next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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A high rip current risk is in place through Sunday. This is due to
SE to S long period swells from Hurricane Ernesto. The high risk
will likely need to be extended into Monday. Please refer to NHC for
official forecasts regarding Hurricane Ernesto.
Ocean seas are forecast to be highest Sunday into Monday, with
heights up potentially 7-8 feet. There is potential for high surf
along the ocean beaches during this timeframe as well as beach
erosion.
Minor coastal flooding is possible for the back bays of Long Island
and across the CT coast of Western Sound early next week during high
tide cycles Sunday through Tuesday as swells build and astronomical
tides increase due to the full moon on Monday.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...High Risk for Rip Currents through Sunday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT
Monday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...DS/MET
NEAR TERM...MET
SHORT TERM...MET
LONG TERM...DS
AVIATION...20
MARINE...DS/MET
HYDROLOGY...DS/MET
TIDES/COASTAL FLOODING...