000
FXUS61 KOKX 291955
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
355 PM EDT Thu Jun 29 2023

.SYNOPSIS...
-- Changed Discussion --
Weak high pressure pushes over the area tonight and then pushes
offshore Friday. A warm front approaches late Friday, before
stalling and weakening nearby Friday night into Saturday. The
front then moves through Saturday night and will then stall
near the area Sunday through the middle of next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH FRIDAY/...
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Subtle height rises take place tonight, with the more noticeable
height rises at 700 mb into Friday. Enough capping will remain in
place between 5 and 10 kft to preclude any precip chances for
tonight and through the day on Friday. Later in the afternoon on
Friday a warm front begins to approach from the west. This will
usher in more in the way of mid level clouds late Friday afternoon
into Friday evening. Previous HREF guidance indicated a slug of
higher PoPs associated with showers and thunderstorms into Central
and East-Central PA by late Friday / Friday evening. The newer HREF
and HRRR guidance, along with the RGEM guidance is less aggressive
and leads to further evidence of dry conditions continuing through
all of Friday evening.

The main question for the period is how much haze and smoke gets
into the area, and how far east does it get. There remains a lot of
uncertainty with regard to visibility and the precise air quality
impacts from smoke and haze associated with the Canadian wildfires
and its associated smoke plume. For now have settled in with mainly
5 to 7 statue miles visibilities, but 3 to 4 statue miles visibilities at
shorter durations are likely to continue to take place for western
portions of the CWA.

Temperatures are expected to average at normal levels for tonight
and into Friday. Look for partly cloudy skies tonight, as clear
skies may be relegated to far eastern areas as haze will be more
prevalent the further west one goes. Mostly sunny conditions are
anticipated Fri morning, although haze will be prevalent, followed
by more in the way of mid level moisture and clouds later in the day
on Friday.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
The newer HREF guidance along with the 12z Thu guidance of the
higher res Canadian and other CAM guidance has it remaining
primarily dry through Friday night. The cap however weakens during
Friday evening. With a warm front going through frontolysis /
weakening it is questionable as to how far east any shower activity
can get. It seems prudent to have a slight chance of showers for at
least a portion of the area Friday night as the warmer and more
humid air mass begins to gradually begins to work in from the west
along with a light onshore flow at and near the sfc out of the SE
take shape. Therefore have gone only with slight chance PoPs for the
western periphery of the CWA (mainly W Orange County) for most of
Friday night. Introduce slight chance PoPs further east closer to
day break on Saturday with some light showers potentially coming in
out of the south off the ocean on a light onshore flow. Temperatures
will not move much Fri night with lows in the 60s, with middle and
upper 60s for the metro areas.

Saturday will feature the more humid airmass getting more of a grip
on the area as sfc dewpoints get into the middle and upper 60s. What
is left of a warm front will stall nearby. The GFS and HRWFV3 get
PWATs about 1.5 inches by the afternoon, with the NAM 3 km delaying
the arrival of the higher water content relatively speaking. BUFKIT
forecast soundings indicate a good deal of mid level moisture, with the
sfc to 5 kft layer being relatively drier, especially for eastern
portions of the CWA. Slight chance to chance showers seems prudent
for the time being for daytime Sat. Kept thunder chances minimal as
the instability remains back to the west for the first half of the
weekend with the area not yet in the warm sector.

Temperatures will be a few degrees warmer Fri night, and perhaps a
few degrees cooler on Saturday due to more in the way of clouds.
Temperatures overall will be right around the seasonable norms.

With regard to the smoke and haze, after consultation with the NYDEC
and inspection of the HRRR, the Canadian RAQDPS, and the
experimental RRFS there remains some question as to how long the
plume lingers across a good portion of the CWA. At this time for Fri
night it appears that the higher concentrations of haze and smoke
may begin to dissipate and start to lift further north, with the
higher probability of this taking place for Sat.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
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After the passage of a cold front on Saturday, a warm front will
bring increasing moisture and lift Saturday night The warm front
then begins to pass through the forecast area Saturday night. Rain
chances will continue until Monday morning with the passage of the
warm front. Slight chance of thunderstorms early in the night.

An unsettled period is expected in the long term as a weak frontal
system lingers over the area. Based on the 12Z GFS a plume of high
moisture air consisting of 2-2.25 inch PWAT values will move into
the area Sunday. These PWATs are above the max moving average for
this time of year per SPC`s Sounding Climatology Page. This has been
consistent in the last several model runs. Elevated PWATs just under
2 inches (reaching about 2 inches, at times) sticks around through
Tuesday. After mainly zonal flow aloft on Sunday, a trough will
approach and be slow to pass to our east. This set up will likely
result in showers and thunderstorms each day. At this time,
widespread hydrologic impacts are not expected. The WPC has outlined
portions of northeast NJ and the Lower Hudson Valley in a marginal
risk in the Day 4 and 5 ERO. Additionally, the experimental CSU
machine learning severe weather forecasts have our area in a
marginal risk of severe weather each day in the forecast, mostly
from daily diurnal convection.

Temperatures will run right about average, with highs in the 80s
each day and a slight warming trend. Given the high moisture and
lack of clear nights, lows will be well above average, in the upper
60s to low 70s.
-- End Changed Discussion --

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
Weak high pressure remains over the area through Friday.

VFR today with a NW flow at most terminals right now. Coastal
sea breezes have developed and are expected to impact terminals
this afternoon.

Some haze from smoke is likely from the NYC metros north/west
during much of the daytime hours. The haze could cause vsby to
drop to MVFR at KEWR and KTEB this afternoon through the
evening. The sea breeze should help improve vsby at the
terminals it passes through.

Winds tonight become light and variable tonight, then the
synoptic flow becomes southerly for Friday. No plans at this
time to include any haze from the smoke in the forecast for
Friday at this time.

THE AFTERNOON KJFK, LGA, AND EWR HAZE POTENTIAL FORECAST IS
YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF
CLOUD.

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

Amendments possible for timing of sea breezes this afternoon.

Low confidence in vsby forecast this afternoon and evening with
smoke haze.

OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY...

Friday: VFR.

Friday night: Chance of showers/MVFR cond, with possibly a tstm at
KSWF.

Saturday and Sunday: Showers likely and chance of tstms, mainly each
afternoon/evening. MVFR expected, IFR possible with this activity.

Monday and Tuesday: MVFR possible. Chance of mainly
afternoon/evening showers and thunderstorms.


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

&&

.MARINE...
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No advisories are expected for the coastal waters on a light S to
SE flow to round out the week. Ocean seas subside closer to 3 ft Fri
and Fri night. The S to SE flow then may increase somewhat to begin
the weekend with ocean seas getting closer to 4 ft by early Sat
evening.

Sub-advisory conditions are expected to prevail Saturday through
Wednesday with a weak pressure gradient in place and a lack of
significant swell. However, there will be a slight chance to
chance of thunderstorms each day, which could result in locally
hazardous conditions.
-- End Changed Discussion --

&&

.HYDROLOGY...
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At this time there are no anticipated hydrologic impacts through
Wednesday. Localized impacts may become possible towards Sunday,
but confidence of occurrence is low at this time.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
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There is then a moderate risk of rip current development for
Friday & Saturday everywhere.

With astronomical tides increasing this weekend as we head toward a
full moon on Monday, minor coastal flooding will be possible with
the evening high tide cycles Saturday through at least Monday. Areas
most likely to be affected are the south shore bays of Nassau,
Queens and Brooklyn, Staten Island, and Southern Fairfield/Westchester
Counties.
-- End Changed Discussion --

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk until 9 PM EDT this evening for NYZ080-
     081.
NJ...None.
MARINE...None.

&&

$$
SYNOPSIS...JE/BR
NEAR TERM...JE
SHORT TERM...JE
LONG TERM...BR
AVIATION...BC
MARINE...JE/BR
HYDROLOGY...JE/BR
TIDES/COASTAL FLOODING...