000
FXUS61 KOKX 030013
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
813 PM EDT Sun Jul 2 2023

.SYNOPSIS...
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A warm front to the north tonight followed by a weak cool front
or trough passage on Monday will result in unsettled weather. A
weak cold front will then work across the area on Tuesday,
followed by high pressure building in for the middle of the week.
Another frontal system will slowly approach from the west late in
the week into next weekend.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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An MCV spinning across south central NYS state will send a line
of showers with embedded thunderstorms east the first half of
tonight and through the forecast area. Conditions remain
marginal for severe/strong convection with moderate to a high
CAPE environment and 25-30kt of deep-layer shear (weak).
However, there is uncertainty as we lose insolation and the
airmass gradually stabilizes. The NAM is a bit more bullish in
maintaining the instability, likely due to a stronger southerly
LLJ maintaining a feed of less stable air from the south. We
will likely be somewhere in the middle with showers and embedded
thunderstorms.

As for the heavy rainfall potential with any thunderstorms
tonight, 12Z HREF maintains low probabilities of greater than
1" in an hour anywhere in the CWA, though there is a 10% prob of
greater than 3" in 3hrs across northeastern NJ, which is above
flash flood guidance of about 2". The airmass in place has PWAT
values around 2", and though cells should be moving with
15-20kts of midlevel flow, the potential for urban and poor
drainage flooding remains across these areas through the
evening.

The convective activity should weaken as it moves east through the
overnight and become elevated. Have maintained the slight
chance/isolated thunder chances into the overnight across
portions of the CWA to account for this.

Fog across the coastal areas may develop early in the morning
with moist environment and light southerly flow. Confidence is
low on this occurrence, so have left out of the gridded database
for now.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Any overnight convection should be east of the area by daybreak.

Weak H5 ridging aloft gives way to a mid level trough moving through
the area by late Monday. The trough axis moves toward the area from
the OH Valley but remains west of the CWA by evening. At the
surface, a weak prefrontal sfc trough approaches during the
afternoon. The airmass in place becomes destabilized by
afternoon, with increasing chances of showers and thunderstorms.
Model soundings are showing 1000-1500J/kg of SBCAPE along with
some bulk shear, 25-30kts. SPC has placed the entire area in a
marginal risk for severe thunderstorms, with damaging winds and
hail possible with any storm. In addition, given the high PWAT
airmass still largely in place, cannot rule out the possibility
of an isolated flash flood especially north and west of NYC.

850mb temperatures warm in to the upper teens, 17-19C which will
yield a warmer day than Sunday near or just above 90 for NYC and the
urban corridor, and mid to upper 80s elsewhere.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Models have clearly trended slower with the upper trough lifting out
of the Northeast on Tuesday. The latter of which will also send a
weak cold front through the area. Environment will be weakly sheared
with moderate CAPE values of 1000-1500 J/KG. Thus, chances for
scattered convection have come up for Tuesday with the best chances
being in the afternoon, possibly lingering into the early evening
along the coast. In addition, high PW values will remain close to 2
inches, but storm movement should keep any flood threat to the
minor, nuisance variety.

We will also be heading into the warmest part of the summer thus far
early in the season. There is the potential for a couple of days
(Wed and Thu) of 90-degree heat away from the immediate coast. With
the aforementioned cold frontal passage potentially being more
active Tuesday, highs look to fall short of 90 that day. Heights
begin to build with the departure of the upper trough and ridging
builds in from the west for the mid week period. 85h temps around
18C will result in surface temps 5-8 degrees above normal. Airmass
looks to dry out enough with a W/SW flow to keep heat indices close
to the ambient temperature.
So at this time, the threat for heat advisory criteria is low.

The is a chance for isolated convection Wednesday and Thursday
afternoons, mainly inland. However, airmass will be drier with some
mid level capping.

For the end of the week, heights fall with the approach of another
upper trough. The trend has been for a slower progression with the
front possibly stalling west of the area for much of the weekend.
Temperatures will be cooler in the 80s, largely due to an increase
in cloud cover, onshore flow, and possible scattered convection.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
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A frontal boundary remains north of the terminals tonight into
Monday with a cold front approaching from the west on Monday.

Mainly MVFR conditions expected tonight with some localized IFR
conditions. There will be showers moving in this evening along
with some thunderstorms mid to late this evening, mainly between
01Z and 04Z Monday. The showers and thunderstorms move east of
NYC terminals late this evening towards the overnight period
mainly between 02Z and 06Z Monday.

Then, a lull in the shower and thunderstorm activity is
forecast for much of the remainder of the TAF period with mainly
dry conditions. MVFR conditions expected to remain overnight
into Monday morning with possible IFR. There could be another
round of rain showers Monday morning mainly between 09Z and 15Z.

Improvement to VFR expected late Monday morning into Monday
afternoon. The next round of showers and thunderstorms is
forecast to start moving in after 00Z Tuesday.

Winds will be mainly S-SW near 5-10 kt for much of the TAF
period.


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

Timing of TSRA and categorical changes could be 1-3 hours off from
forecast. IFR possible early Monday. There could be fluctuations
between categories overnight into Monday.

OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...

Monday night: SHRA/TSRA mainly in the evening. Mainly MVFR
conditions. Chances for SHRA/TSRA decrease overnight. IFR possible.

Tuesday: Chance of SHRA/TSRA with MVFR possible. SHRA/TSRA taper off
late evening with VFR returning thereafter.

Wednesday: Mainly VFR. Slight chance of SHRA/TSRA across interior
and Southern CT terminals afternoon into early evening.

Thursday: Mainly VFR. Slight chance of SHRA/TSRA north and west of
NYC terminals afternoon into early evening.

Friday: MVFR possible. Chance of showers. Slight chance of
thunderstorms for NYC terminals, interior and Southern CT terminals
afternoon into early evening.

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

.MARINE...
Winds and seas are expected to generally be below SCA levels
through the upcoming week due to weak gradient winds across the
waters. Waves on the eastern ocean zone may approach 5 ft
tonight into Monday afternoon with a southerly flow building
seas.

&&

.HYDROLOGY...
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There is a chance for areas of localized flooding into this
evening with any thunderstorms that do develop across the area.
Mainly nuisance and urban poor drainage is expected, but an
isolated flash flood cannot be ruled out across northeastern NJ
and the Lower Hudson Valley. For Monday, mainly nuisance
flooding is possible with any thunderstorms mainly north and
west of NYC.

No hydrologic issues are expected Tuesday through Sunday.
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&&

.TIDES/COASTAL FLOODING...
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In terms of rip currents...A mixture of 3ft@8 sec SE swells and 2-3
ft S wind waves will have a borderline moderate to high risk of rip
development Monday. Based on climo, higher confidence in high
risk for Suffolk County beaches, with threat for high risk
possible for western beaches late afternoon w/ sea breeze
development.

Rip development threat should ease back to solid moderate on
Tuesday as S and SE swells subside back to around 2 ft.

In terms of coastal flooding...Astronomical tides continue to
increase through Tuesday with the approach of a full moon. Generally
localized minor coastal flood impacts for tonight and Monday night
high tide for southern Queens, southern Westchester and southern
Fairfield county, with a bit more widespread minor flooding (up to
1 ft of inundation) for Southern Nassau county.

Additional rounds of minor flooding are possible with the
evening/night high tide cycle through midweek.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...High Rip Current Risk from 6 AM EDT Monday through Monday
     evening for NYZ080-081.
     Coastal Flood Advisory until 11 PM EDT this evening for NYZ179.
     Coastal Flood Advisory from 7 PM Monday to midnight EDT Monday
     night for NYZ179.
NJ...None.
MARINE...None.
-- End Changed Discussion --

&&

$$

SYNOPSIS...DBR/DW
NEAR TERM...DBR/DW
SHORT TERM...DBR
LONG TERM...DW
AVIATION...JM
MARINE...DBR/DW
HYDROLOGY...DBR/DW
TIDES/COASTAL FLOODING...NV