000
FXUS61 KOKX 072043
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
443 PM EDT Mon Aug 7 2023
.SYNOPSIS...
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A warm front moves through tonight, followed a cold front for
Tuesday, with high pressure building in for Tuesday night. High
pressure takes control on Wednesday, followed by a storm system
on Thursday. High pressure then returns for Friday and lasts
into at least part of Saturday before another system potentially
impacts us later in the weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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A warm front will move through the region tonight as a slowly
approaching shortwave trough remains just west of the area. A line
of showers and thunderstorms is expected to be over eastern
Pennsylvania early this evening. Some of these storms could become
strong to severe, even as it begins to move into western portions of
the forecast area (western Orange and western Passaic counties).
However, CAMs continue show that this line will weaken as it moves
through the forecast area, primarily due to loss of instability
associated with daytime heating. Despite this, the synoptic setup of
an overnight warm front moving through with a slowly moving
shortwave west of the region cannot be ignored and although the
threat for severe weather and flash flooding seems to be lower, it
is still not out of the question. The main threat will be gusty
winds. If conditions continue to be severe, an isolated tornado is
also possible as helicity values approach 300 m^2/s^2, again mainly
for areas north and west of the city. CAPE values of 1000-2000 J/kg
by around 6 pm over this area look to fall pretty quickly
thereafter. At this time, thinking is that the best chances for any
severe storms will be west of the Hudson, with chances decreasing
westward this evening. In coordination with SPC and surrounding
offices, did not opt to put any portion of the forecast area in the
tornado watch to the west due to the uncertainty in the forecast,
but western portions may be added later in the evening given radar
trends at the time.
Another feature to watch is that the NAM Nest wants to develop an
area of showers and thunderstorms late tonight along a surface
trough or a weak area of low pressure, after 2 am that primarily
affects areas east of the Hudson. Kept chance POPs in for the
entire night, but did not go any higher due to uncertainty as
the NAM and certain runs of the HRRR are showing this.
Additionally, while heavy rain moved through portions of the
forecast area this morning, with radar estimates of over 2" in some
spots, enough time will likely elapse for this rain to have run off.
The line of storms looks to be progressive enough to preclude flash
flooding for much of the forecast area. However, flash flooding
cannot be totally ruled out, especially for the metro area where it
takes less rain for flooding. An average additional 1/4 inch to an
inch of rainfall is forecast across the area. Locally heavier
amounts are possible in any thunderstorms, with PWATs over 2" noted
in most models.
With dew points in the 70s, conditions will be warm and dry, with
overnight lows only dropping to the lower 70s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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The upper shortwave trough axis moves east late in the day Tuesday
into Tuesday night as the cold front pushes offshore earlier in the
day. Low pressure well to the north of the area slowly strengthens.
With the trough still in the area, the chances for showers and
thunderstorms continues, but will not be as widespread as Monday,
nor as strong, as much of the dynamics should remain north and east
of the area.
With weak high pressure building late Tuesday into Tuesday
night, a drier air mass will be in place. Tuesday night will be
dry with dew points falling into the upper 50s to around 60.
Lows will be near normal for this time of year.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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The flow aloft becomes less cyclonic on Wednesday with weak high
pressure building in at the surface. This should be enough to keep
us dry through the day. Low pressure tracking through SE Canada then
drags a cold front toward the forecast area. This along with the
potential of a weak offshore low passing nearby brings chances of
showers and maybe a thunderstorm Thursday into Thursday evening.
High pressure returns for Friday with a dry day, then low pressure
emerging from the northern Great Lakes Region is progged to pass to
our north Saturday night into Sunday. This will bring a chance of
showers and thunderstorms mainly from Saturday afternoon through
Sunday evening. The flow aloft may then become slightly cyclonic on
Monday, bringing a diurnal threat of a shower or thunderstorm.
Temperatures through the long term period are expected to be near
normal with with high temperatures mostly in the lower and middle
80s.-- End Changed Discussion --
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
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A warm front slowly lifts north of the terminals this evening. A
cold front then follows late Tuesday morning.
Mainly low end VFR and high end MVFR this afternoon. The first round
of showers has moved through all terminals. Lingering showers are
now moving through KBDR and KISP and will eventually reach KGON. Due
to the isolated nature have just kept a VCSH. The NYC terminals and
north and west likely remain dry through this evening.
Another round of showers and thunderstorms is expected early tonight.
Have kept a TEMPO for TSRA for the NYC and Lower Hudson Valley
terminals, mainly after 00Z. There is quite a bit of uncertainty
with the strength of these showers and thunderstorms and amendments
are likely. Otherwise, back down to MVFR-IFR cigs is forecast
tonight. Showers then linger early Tuesday. There is some potential
for thunderstorms again in the 05-10z time frame, but confidence too
low to add in the TAF and have kept -SHRA.
SE winds 10-15 kt with gusts 18-25 kt this afternoon, strongest
along the immediate coast. The highest wind speeds and gusts should
begin to subside this evening. Winds will then veer to the SW late
tonight at 10kt or less. Winds pick up again early Tuesday out of
the SW-W, with gusts 20-25 kt possible.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Brief IFR cigs are possible after midnight. Improvement to VFR may
happen a few hours earlier on Tuesday afternoon.
Uncertainty in timing and strength of showers/thunderstorms
early tonight. Potential is there for strong to severe thunderstorms.
OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday Afternoon: Improvement to VFR likely by early afternoon.
Showers and an isolated thunderstorm possible in the afternoon and
evening with MVFR conditions. SW wind gusts 20-25 kt possible.
Tuesday night through Wednesday: VFR. W wind gusts around 20 kt.
Thursday: VFR.
Thursday Night-Friday: Mainly VFR. Chance of showers and MVFR. A
slight chance of thunderstorms Friday afternoon.
Saturday: Mainly VFR. Slight chance of afternoon showers and
thunderstorms mainly for NYC north and west.
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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25 kt gusts expected on the ocean waters tonight as seas build
to near 5 ft. SCA in effect for the ocean tonight into Tuesday.
Mainly sub- SCA conditions remain elsewhere tonight going into
Tuesday but some waters will have occasional gusts to 25 kt.
Potential for more widespread SCA conditions Tuesday night into
Wednesday with the passage of the cold front. The pressure
gradient then weakens Wednesday afternoon. Ocean seas may
however remain elevated at advisory levels all the way through
the day Wednesday.
Thereafter, mainly sub-SCA conds expected on all waters into late
week.-- End Changed Discussion --
&&
.HYDROLOGY...
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The best chance for isolated to scattered flash flooding will
be tonight into early Tuesday morning with a line of showers and
thunderstorms that move into the forecast area from the west.
Rainfall amounts of 1/4 to 1 inch are forecast across the area
with the potential for localized higher amounts, possibly as
much as near 2 inches. However, the storms are expected to be
progressive and the threat for flash flooding is slightly lower
than previous forecast. The Weather Prediction Center continues
its slight risk for excessive rainfall through tonight for much
of the forecast area.
Heavy rain is possible late Thursday into Friday, but at this
time there remains too much uncertainty to determine any
potential hydro risk.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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A high rip current risk for all Atlantic-facing beaches continues
through this evening. A high risk for rip current development
remains high on Tuesday as seas build to around 5 ft with gusty 15
to 20 kt winds.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...High Rip Current Risk until 9 PM EDT this evening for NYZ075-
080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JP
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...JC
AVIATION...JT
MARINE...JC/JP
HYDROLOGY...JC/JP
TIDES/COASTAL FLOODING...