722
FXUS61 KOKX 171015
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
615 AM EDT Sat Aug 17 2024
.SYNOPSIS...
High pressure remains centered offshore today as a weak low tracks
through the Great Lakes. The low approaches on Sunday, with an
associated warm front lifting through 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.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Increased PoPs across western half of the area this morning with
some light rain showers pushing east thru NJ and the Lower
Hudson Valley. This activity will remain light and brief where
it occurs, and likely dissipates into mid morning as it runs
into ridging. Otherwise, forecast on track and previous discussion
follows.
Upper ridging in place locally shifts to the east as surface high
pressure remains centered offshore today. Digging trough over the
Great Lakes begins to approach, and a frontal system on the
leading edge will begin to approach.
While much of the day appears dry across the bulk of the forecast
area, increasing moisture and lift should stir a few showers on
the far western edge of the region, mainly across the Lower
Hudson Valley and further from the influence of the offshore
ridging. Otherwise, increasing cloud cover and warm, with
temperatures this afternoon topping out near 80 for most. Given
the flow, the elevated smoke plume that has been in place the
last few days shifts east and offshore.
The shower activity expands in coverage this evening and tonight
with passing shortwave energy, but still appears mostly confined
to the western half of the region. Some varying solutions from
the 00Z CAMs, with the NAM 3km much less enthused with rainfall
tonight, and the HRRR much more bullish and farther east with
the placement. For now, opted for lower likely PoPs (60%) given
the disagreement, with this mainly extending over NE NJ and the
Lower Hudson Valley and decreasing to the east. Not entirely out
of question a few embedded thunderstorms develop tonight as
well, though this remain rather limited.-- End Changed Discussion --
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Unsettled start to the week as the upper trough and frontal system
track through the Northeast and bring several periods of rainfall.
Scattered showers around Sunday morning should lessen in coverage
by lunchtime, and much of the afternoon could remain dry, especially
east. Into the evening, rain chances increase once again as a
frontal boundary begins to approach. Limited shear and instability
should keep activity mainly sub-severe and disorganized, but can`t
rule out thunderstorms. Of greater concern is the potential for
training convection and heavy downpours given a persistent moisture
feed from the south increasing PWATs to near 1.75" during this time,
raising the risk of heavy downpours that could lead to flooding.
This threat appears highest from NYC on north and west, and lines
up with where WPC currently has a slight risk for excessive rainfall
on Sunday. Though still some uncertainty with the placement of the
axis of heaviest rainfall, which will be critical in fleshing out
the nature and location of the threat.
A cold front follows Monday into Monday night with the potential
of a weak wave forming along the boundary as it moves through
the region, instigating another round of showers and thunderstorms.
There remains the potential for locally heavy rainfall, as well
as an isolated flash flood threat with this activity. Rain chances
finally start to lower Monday night into early Tuesday as the
complex progresses east and a much drier regime begins to take
hold. Total QPF through this period averages around a half inch
across eastern areas, to between 1 and 2 inches from NYC and
points north and west.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
It appears that a cold front will be over us or just shifted through
during Tuesday morning. High pressure will have a tough time
building behind its passage during the rest of Tuesday as an upper
trough axis remains over us. Chance of showers at any point of the
day, but overall it should be dry most of the time. Can`t completely
rule out a thunderstorm in the afternoon due to the cold pool aloft,
but will leave it out of the forecast for now. The trough axis
shifts east during Wednesday, and with limited moisture, it should
be a dry day. The flow aloft flattens for Thursday and Friday with a
continuation of dry weather as surface high pressure builds in.
Highs only in the 70s for Tuesday through Thursday, then around 80
on Friday.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
Weak high pressure remains in control today, then a warm front
approaches from the west tonight.
Conditions across the area terminals will vary from VFR to IFR
through around 12z, then improving to VFR everywhere by late
morning. MVFR returns tonight with a chance of showers, but showers
are more likely towards Sunday morning.
SE winds under 10kt increase to around 10kt by noontime,
remaining SE tonight at 5-10kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence in cigs through approx 13-14z as categories can vary
from VFR to IFR until around this time. Overall better chances of
staying VFR and not lowering to IFR until this time are at KEWR and
KTEB. KLGA has a chance to stay VFR as well, but not as likely as
KEWR/KTEB. KJFK stands a decent chance of improving to at least MVFR
by this time.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Tonight: MVFR in showers, mostly late.
Sunday and Monday: MVFR or lower in SHRA/TSRA.
Tuesday: Mainly VFR. MVFR or lower possible in any SHRA...mainly
eastern terminals.
Wednesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Rough ocean seas and long period swells will persist this weekend
and into early next week as distant TC Ernesto passes well offshore
in the open Atlantic. This will also lead to rough conditions
around inlets. Please refer to the National Hurricane Center for
official forecasts regarding Hurricane Ernesto.
A Small Craft Advisory is in effect for the ocean zones through
Sunday night for elevated swells increasing toward 7 ft. This
will likely need an extension through at least Monday with lingering
seas.
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.
&&
.HYDROLOGY...
Locally heavy rainfall is possible Sunday into Sunday night,
particularly west of the NYC metro and Hudson River. This
threat expands to much of the area Monday into Monday night.
Total rainfall amounts range from around a half inch east to 1
to 2 inches from NYC metro on north and west. Locally higher
amounts are possible. Isolated to scattered instances of flash
flooding is possible across the more flood prone areas of NE NJ
and adjacent areas of the Lower Hudson Valley, and perhaps as
far east as NYC. A more widespread threat for localized flash
flooding, along with nuisance flooding of urban and poor
drainage areas, sets up on Monday.
No additional hydrological concerns follow Tuesday through late next
week.
&&
.TIDES/COASTAL FLOODING...
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 to 7 ft. 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.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Sunday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Monday for ANZ350-353-355.
&&
$$
SYNOPSIS...JC/DR
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...JC
AVIATION...JC
MARINE...JC/DR
HYDROLOGY...JC/DR
TIDES/COASTAL FLOODING...