560
FXUS61 KOKX 161020
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
620 AM EDT Fri Aug 16 2024

.SYNOPSIS...
Weak high pressure remains in place through tonight. A weakening
low pressure system then slowly approaches from the Great Lakes
this weekend. A warm front then lifts through early Monday as
the center of the low redevelops near or over the region. The
associated cold front passes through later Monday, with a
secondary frontal passage into Tuesday. High pressure then
builds in behind the system for mid to late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The forecast was updated to account for some low stratus
heading into SE CT for a few hours this morning before
dissipating. The forecast is otherwise mostly on track.

Surface high pressure will be accompanied by ridging aloft. The
combination of the two will keep us dry today, and with still enough
of a ridge aloft tonight, we should be able to get through the night
without any showers. Can`t rule out a slight reduction in surface
visibility this afternoon mainly NW of the city as per the HRRR
smoke forecast, but not enough confidence to include in the
forecast. Just expect a hazy appearance of the sky outside of
cloud cover. NBM looked good for temperatures through tonight,
and dewpoints will be a little higher than what they were
yesterday, so it should feel a little more muggy. Patchy fog
possible tonight, primarily over CT and eastern LI.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
Low pressure slowly tracks east and weakens across the Great Lakes
this weekend. A leading warm front approaches, but is progged to
remain west of the forecast area through at least Sunday afternoon.
With the slow eastward progression of the system, shower chances
will also slowly advance east across the area during Saturday.
Likely PoPs don`t begin until late Saturday night, and are probably
limited to west of around the Hudson River during Sunday. Eastern
portions of LI and CT may end up dry for the entire period. Thunder
possible starting Saturday afternoon, but isolated in nature until
perhaps Sunday afternoon when chances over the western zones
increase.

PWATs increase, and chances of at least minor flooding begin to
increase Sunday afternoon, mainly over NE NJ and adjacent areas of
the Lower Hudson Valley. This will be when more efficient rains
could occur as the convective threat increases, and lift is enhanced
by both an increasing low level jet and the left-exit region of an
upper jet streak in the vicinity. See the hydrology section
below for more details. NBM was used for temperatures through
the period.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
An approaching upper level trough, with a frontal system on the
leading edge, shifts into the Northeast early next week. A warm
front lifts through Sunday night into early Monday, with guidance
indicating the development of a secondary low which passes near or
over the region Monday morning. The attendant cold front tracks
through later in the day, with perhaps a secondary front Monday
night or early Tuesday.

Two primary periods of precipitation from this system look to
develop Sunday night into early Monday with the warm front, then
additional activity along and ahead of the cold front later Monday.
Parameters appear rather tame in terms of severe weather from this
system, relatively low instability and shear, though increased
moisture with the SW flow will allow locally heavy downpours that
could lead to nuisance flooding at times. A subsequent NW flow
develops behind it Tuesday, ushering in a much drier air mass.
Surface high pressure begins to build in from the Midwest into
midweek and should allow relatively dry and tranquil conditions,
though the lingering trough aloft could support additional cloud
cover in cyclonic flow.

Temperatures look to average near, if not slightly below, normals
for mid to late August, with highs generally into the upper 70s to
around 80, and lows falling back into the 50s and 60s. The national
blend was largely followed for this update, with only subtle
adjustment.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
Weak high pressure generally remains in control through the TAF
period.

VFR forecast.

Winds light and variable this morning as high pressure moves
overhead. The flow goes southerly this afternoon as the high shifts
offshore. Speeds remain at or under 10 kt.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Timing of onset of southerly winds may be off by an hour or two.

OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...

Saturday: Showers likely with chance of tstms, especially in the
afternoon/early evening, and especially from the NYC metros north
and west. MVFR or lower conditions possible.

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

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
Sub-advisory conditions on all waters today. Seas then begin to
increase tonight and into the weekend with energy from distant
Hurricane Ernesto reaching the coast. Waves will largely be 5-7 feet
Friday night through the weekend. Small Craft Advisories are in
effect for all the ocean zones beginning tonight and lasting through
Sunday. SCA conditions likely persist on the ocean waters
through Monday night with elevated swells up to 8 ft. These
should lower by late Tuesday, with sub SCA conditions then
expected on all waters thereafter.

&&

.HYDROLOGY...
Rainfall from Saturday night through Monday is expected to range
from around a half inch to an inch for a good portion of the area,
however amounts could ramp up towards 2 inches NW of the city in a
relatively short distance. Given some uncertainty as to where this
tight gradient sets up, confidence isn`t very high regarding the
flash flooding potential. Considering that the higher amounts would
more likely occur over areas typically more prone to flash flooding
(portions of NE NJ and adjacent areas of the Lower Hudson Valley), a
marginal to slight risk of flash flooding exists. Best guess right
now is that any impacts would not start until Sunday afternoon at
the earliest, and would more likely happen any time from Sunday
night through Monday night. Can`t rule out flash flooding elsewhere,
but any flooding impacts would be more in the minor category.

No hydrological concerns follow thereafter through late next
week.

&&

.TIDES/COASTAL FLOODING...
There will be a high rip current risk today, mainly in the afternoon
into early evening. This high risk then continues through Saturday
and likely lasts through the entire weekend.  This is due to SE to S
long period swells from Hurricane Ernesto. Please refer to NHC for
official forecasts regarding Hurricane Ernesto.

Ocean seas are forecast to be highest Sunday into Monday, with
heights up to 8 feet. There is potential for high surf along the
ocean beaches during this timeframe as well as beach erosion. In
addition, the high risk of rip currents will likely extend through
early next week.

Minor coastal flooding is possible early next week during high tide
cycles Sunday through Tuesday as swells build and astronomical tides
increase due to the full moon on Monday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Saturday evening for NYZ075-080-
     081-178-179.
NJ...None.
MARINE...Small Craft Advisory from 10 PM this evening to 6 PM EDT
     Sunday for ANZ350-353-355.

&&

$$

SYNOPSIS...JC/DR
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...DR
AVIATION...DR
MARINE...JC/DR
HYDROLOGY...JC/DR
TIDES/COASTAL FLOODING...