000
FXUS61 KOKX 041955
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
355 PM EDT Fri Aug 4 2023
.SYNOPSIS...
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A cold front will move through the area tonight. High pressure
returns for the weekend. A frontal system impacts the area
Monday into Tuesday. High pressure briefly builds in Wednesday,
with another area of low pressure potentially moving through by
late week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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A Severe Thunderstorm Watch is in effect for Orange and Putnam
Counties until 8 PM this evening.
A broken line of strong to severe discrete thunderstorms is
approaching from the northwest along a cold front, currently
stretched from central PA to northern NY. Latest SPC mesoanalysis
currently has about 1500 J/kg of SBCAPE across the Lower Hudson
Valley, which is expected to increase to close to 2000 J/kg by later
this afternoon and remain uncapped. This combined with effective
bulk shear values of 30-35 kt could result in storms producing
damaging wind gusts and isolated large hail. The thinking right
now is that any activity will weaken once making it through
northern portions of the Lower Hudson Valley and then continue
below severe criteria. Heavy downpours are also expected with
these storms. Latest MRMS radar estimates show isolated areas
that received a quick 0.5 to 1 inches in an hour. WPC currently
has the area in a marginal risk for excessive rainfall. Flash
flooding is not expected and minor poor drainage flooding is the
main threat. Out ahead of the broken line of storms, very
isolated warm advection showers are ongoing across Long Island
and CT.
Showers and thunderstorms will end from west to east tonight,
exiting far eastern locations around 4-6 AM Saturday morning. Some
slightly cooler and drier air will advect in behind the front, but
not expecting a big airmass change. Lows will be in the upper 50s to
upper 60s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
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Upper level trough axis shifts offshore early Saturday morning
and the flow aloft becomes more zonal. At the surface, high
pressure noses in from the northwest as the cold front departs
offshore.
The warmest day in about a week is expected on Saturday, with
temperatures back to, or just above, normal. Highs will be in the
low to mid 80s. The air will still have a comfortable feel to it
with dewpoints in the upper 50s to lower 60s. Given subsidence
through the column, dry are sunny conditions are expected.
Temperatures Saturday night will be limited as high clouds spread
over the area from the west. However, slightly below normal lows are
expected, in the upper 50s across the interior and lower 60s to
lower 70s elsewhere.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
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Changes have been relatively minor in the extended period.
Weak ridging is in place on Sunday as surface high pressure drifts
through the Northeast and offshore. This should maintain dry
conditions through the day, though cloud cover builds ahead of an
approaching low pressure system moving into the Great Lakes. By
Monday, the attendant warm front likely lifts through the region,
with increasing rain chances as it does. Still some uncertainty with
exact timing and placement of the surface features, but depending on
where the low occludes and the warm sector sets up will better
determine the thunderstorm threat. At this time, a few thunderstorms
are possible ahead of the trailing cold front late Monday or early
Tuesday, with a relatively low severe threat. WPC currently has a
marginal risk for excessive rainfall across northern NJ and portions
of the lower Hudson Valley. Fortunately, the system appears to be
progressive enough to limit a more significant flood threat.
High pressure builds in late Tuesday into Wednesday, then offshore
with a return southerly flow setting up. Another area of low
pressure may track east into the Great Lakes by Thursday, bringing a
return to rain chances into late next week.
Temperatures will remain relatively seasonable through the period,
with highs generally in the low to mid 80s, and daytime dew pts in
the 60s. Primarily followed the national blend of model guidance for
this update.-- End Changed Discussion --
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
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An approaching cold front will move across tonight.
Bkn line of tstms will sink SE toward the area from late day into
this evening, with likely late day impact at KSWF. Impact at most
other terminals doubtful and timing uncertain as activity should
weaken after dark. Delayed possible TEMPO impact at the NYC metros
until 01Z-04Z, and an hour or two later farther east.
S-SW winds 10-15 kt with an ocnl gust to 20 kt will veer more to the
SW and diminish this evening, then shift light NW late tonight with
cold fropa and veer N after 12Z-13Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence on thunder chances and timing this evening as
storms will be weakening on approach.
OUTLOOK FOR 18Z SATURDAY THROUGH MONDAY...
Saturday afternoon through Sunday: VFR.
Monday: Mainly VFR.
Monday night: Showers/tstms likely with MVFR or lower cond.
Tuesday: Mainly VFR.
Wednesday and Thursday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Winds and waves will continue to increase ahead of a cold front this
afternoon. Winds should largely stay below 25 kt, but an occasional
gust to 25 kt cannot be ruled out. Ocean seas should also build to 4
ft, but should stay below 5 ft. Winds and seas subside behind the
cold front passage late tonight into Saturday morning.
Winds and seas will remain below SCA levels across the forecast
waters Sunday through Monday. Increasing southerly flow ahead of a
frontal system Monday may produce marginal SCA wind gusts and seas
on the ocean into early Tuesday. Sub-SCA conds return to all waters
for the middle of next week.-- End Changed Discussion --
&&
.HYDROLOGY...
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Showers and thunderstorms late this afternoon and into the evening
may produce locally heavy rainfall mainly north and west of NYC.
Minor nuisance and poor drainage flooding is possible.
There are no significant hydrologic concerns from Sunday through the
late next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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There is a moderate risk of rip current development at the ocean
today and Saturday with a 2-ft 9-10 s period S swell.
The threat of minor coastal flooding has ended. All locations in the
South Shore Back Bays should remain just below minor levels tonight
and then continue to lower the next several days.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...DR
AVIATION...BG
MARINE...DR/JT
HYDROLOGY...DR/JT
TIDES/COASTAL FLOODING...JT